HER2 evaluation for clinical decision making in human solid tumours: pearls and pitfalls

The significant clinical benefits of human epidermal growth factor receptor 2 (HER2)-targeted therapeutic agents have revolutionized the clinical treatment landscape in a variety of human solid tumours. Accordingly, accurate evaluation of HER2 status in these different tumour types is critical for clinical decision making to select appropriate patients who may benefit from life-saving HER2-targeted therapies. HER2 biomarker scoring criteria is different in different organ systems, and close adherence to the corresponding HER2 biomarker testing guidelines and their updates, if available, is essential for accurate evaluation. In addition, knowing the unusual patterns of HER2 expression is also important to avoid inaccurate evaluation. In this review, we discuss the key considerations when evaluating HER2 status in solid tumours for clinical decision making, including tissue handling and preparation for HER2 biomarker testing, as well as pathologist's readout of HER2 testing results in breast carcinomas, gastroesophageal adenocarcinomas, colorectal adenocarcinomas, gynaecologic carcinomas, and non-small cell lung carcinomas.

In ER-Positive, HER2-Negative Breast Cancers, HER2 mRNA Levels Correlate Better with Clinicopathologic Features and Oncotype DX Recurrence Score than HER2 Immunohistochemistry

With the approval of trastuzumab deruxtecan for treating advanced human epidermal growth factor receptor-2 (HER2) low breast cancer (BC), it has become increasingly important to develop more accurate and reliable methods to identify HER2-low BC. In addition, HER2 immunohistochemistry (IHC) has limitations for quantification of HER2. We explored the relationship between HER2 IHC and mRNA levels and evaluated whether HER2 IHC scores and mRNA levels are associated with clinicopathologic features and Oncotype DX Recurrence Score (RS) in estrogen receptor (ER)-positive, HER2-negative BCs. A total of 750 BCs sent for Oncotype DX (ODX) testing were included in this study, and 559 with HER2 mRNA levels were available. There were no statistically significant differences between HER2 0 and HER2-low BC in clinicopathologic variables or ODX RS using HER2 IHC. There was a significant difference in median HER2 mRNA values between HER2 0 and HER2-low (8.7 vs 9.3, P < .001); however, the HER2 mRNA distribution had substantial overlap between these 2 groups with a suboptimal area under the receiver operating characteristic curve (area under the receiver operating characteristic curve = 0.68). A HER2 mRNA value of 9.2 was generated as the optimal cutoff for distinguishing HER2 0 and HER2-low BC. Comparing ER+ BCs with HER2 mRNA high (>9.2) and low (≤9.2) revealed a statistically significant difference in most clinicopathologic variables and ODX RS. From this large cohort of ER-positive, HER2-negative BC, our results demonstrated that HER2 mRNA levels correlated better with clinicopathologic features and recurrence risk as assessed by ODX RS than HER2 IHC scores. Our findings suggest that HER2 mRNA-detecting methods could potentially serve as a quantitative and reliable method for identifying a biologically meaningful group of HER2-low BC. Further study is needed to determine whether HER2 mRNA levels could be more reliable than IHC for identifying which patients will be most likely to benefit from trastuzumab deruxtecan.

HER2 categorical changes after neoadjuvant chemotherapy: A study of 192 matched breast cancers with the inclusion of HER2-Low category

Understanding the changes of HER2 expression after neoadjuvant chemotherapy (NAC) in breast cancer (BC) is more important than ever, since it may allow more patients to access the effective therapeutic drugs targeting HER2-low BC. 192 matched pre- and post-NAC BCs were analyzed. HER2 immunohistochemistry (IHC) was re-evaluated with consensus according to the current ASCO/CAP guidelines. Tumors were categorized into HER2-0 (IHC0+), HER2-low (IHC1+ or IHC2+/ISH-) and HER2-positive (IHC3+ or IHC2+/ISH+) subgroups. 55 (28.6 %) patients achieved pathologic complete response (pCR). HER2-low BC accounted for 75/192 (39.1 %) baseline tumors, and 48/133 (36.1 %) residual tumors. In the non-pCR cohort, 53 (39.9 %) patients had HER2 categorical change after NAC, most commonly converting from HER2-low to HER2-0 (20.3 %, n = 27). Among patients with residual tumor, 25.6 % (11/43) of patients with baseline HER2-0 expression experienced a categorical change to HER2-low after NAC, significantly higher (p < 0.05) in the hormone receptor (HR) positive (9/23, 39.1 %) compared to the HR negative tumors (10 %, 2/20). Exploratory analysis failed to reveal a statistically significant difference in disease free survival and overall survival in non-pCR patients with or without HER2 change. Our results suggest that a substantial number of patients may experience HER2 categorical change after NAC, supporting re-testing of HER2 status in post-NAC residual tumors. Retesting HER2 status may be particularly important for evaluating post-NAC HER2-low status, in order to better assess which patients will more likely benefit from therapeutic drugs targeting HER2-low BC.

HER2 in uterine serous carcinoma: Current state and clinical perspectives

OBJECTIVES

Uterine cancer has the highest incidence and the second-highest mortality rate among gynecologic malignancies in the United States. Although uterine serous carcinoma (USC) represents less than 10% of endometrial carcinomas, it accounts for a disproportionate 50% of tumor relapses and 40% of endometrial cancer deaths. Over the past decade, clinical trials have focused on finding better treatments for this aggressive subtype of endometrial cancer, especially HER2-targeted therapy.

METHODS

We conducted a literature search in PubMed to expand the understanding of HER2 in USC.

RESULTS

HER2 has been established as an important biomarker with prognostic and therapeutic implications in USC. Intratumoral heterogeneity and lateral/basolateral membranous staining of HER2 as well as high discordance between HER2 immunohistochemistry and in situ hybridization are more common in USC than in breast carcinoma. Therefore, a universal HER2 testing and scoring system more suitable to endometrial cancer is needed and currently under investigation.

CONCLUSIONS

This review discusses the clinical perspective of HER2 overexpression/gene amplification in USC, the distinct HER2 staining pattern and the evaluation of HER2 in USC, the resistance mechanisms of HER2-targeted therapy in HER2-positive cancers, and likely areas of future investigation.

Abnormal Uterine Involution May Lead to Atony and Postpartum Hemorrhage: A Hypothesis, With Review of the Evidence

Uterine involution has 2 major components-(1) involution of vessels; and (2) involution of myometrium. Involution of vessels was addressed by Rutherford and Hertig in 1945; however, involution of myometrium has received little attention in the modern literature. We suggest that the pathophysiology of myometrial involution may lead to uterine atony and postpartum hemorrhage. The myometrium dramatically enlarges due to gestational hyperplasia and hypertrophy of myocytes, caused by hormonal influences of the fetal adrenal cortex and the placenta. After delivery, uterine weight drops rapidly, with physiologic involution of myometrium associated with massive destruction of myometrial tissue. The resulting histopathology, supported by scientific evidence, may be termed "postpartum metropathy," and may explain the delay of postpartum menstrual periods until the completion of involution. When uterine atony causes uncontrolled hemorrhage, postpartum hysterectomy examination may be the responsibility of the perinatal pathologist.Postpartum metropathy may be initiated when delivery of the baby terminates exposure to the hormonal influence of the fetal adrenal cortex, and may be accelerated when placental delivery terminates exposure to human chorionic gonadotrophin (HCG). This hypothesis may explain why a prolonged third stage of labor, and delays in management, are risk factors for severe hemorrhage due to uterine atony.

Interobserver and Interantibody Reproducibility of HER2 Immunohistochemical Scoring in an Enriched HER2-Low-Expressing Breast Cancer Cohort

OBJECTIVES

We assessed the interobserver and interantibody reproducibility of HER2 immunohistochemical scoring in an enriched HER2-low-expressing breast cancer cohort.

METHODS

A total of 114 breast cancer specimens were stained by HercepTest (Agilent Dako) and PATHWAY anti-HER2 (4B5) (Ventana) antibody assays and scored by 6 breast pathologists independently using current HER2 guidelines. Level of agreement was evaluated by Cohen κ analysis.

RESULTS

Although the interobserver agreement rate for both antibodies achieved substantial agreement, the average rate of agreement for HercepTest was significantly higher than that for the 4B5 clone (74.3% vs 65.1%; P = .002). The overall interantibody agreement rate between the 2 antibodies was 57.8%. Complete interobserver concordance was achieved in 44.7% of cases by HercepTest and 45.6% of cases by 4B5. Absolute agreement rates increased from HER2 0-1+ cases (78.1% by HercepTest and 72.2% by 4B5; moderate agreement) to 2-3+ cases (91.9% by HercepTest and 86.3% by 4B5; almost perfect agreement).

CONCLUSIONS

Our results demonstrated notable interobserver and interantibody variation on evaluating HER2 immunohistochemistry, especially in cases with scores of 0-1+, although the performance was much more improved among breast-specialized pathologists with the awareness of HER2-low concept. More accurate and reproducible methods are needed for selecting patients who may benefit from the newly approved HER2-targeting agent on HER2-low breast cancers.

The Rochester Modified Magee Algorithm (RoMMa): An Outcomes Based Strategy for Clinical Risk-Assessment and Risk-Stratification in ER Positive, HER2 Negative Breast Cancer Patients Being Considered for Oncotype DX® Testing

INTRODUCTION

Multigene genomic profiling has become the standard of care in the clinical risk-assessment and risk-stratification of ER⁺, HER2^- breast cancer (BC) patients, with Oncotype DX^® (ODX) emerging as the genomic profile test with the most support from the international community. The current state of the health care economy demands that cost-efficiency and access to testing must be considered when evaluating the clinical utility of multigene profile tests such as ODX. Several studies have suggested that certain lower risk patients can be identified more cost-efficiently than simply reflexing all ER⁺, HER2^- BC patients to ODX testing. The Magee equations^TM use standard histopathologic data in a set of multivariable models to estimate the ODX recurrence score. Our group published the first outcome data in 2019 on the Magee equations^TM, using a modification of the Magee equations^TM combined with an algorithmic approach-the Rochester Modified Magee algorithm (RoMMa). There has since been limited published outcome data on the Magee equations^TM. We present additional outcome data, with considerations of the TAILORx risk-stratification recommendations.

METHODS

355 patients with an ODX recurrence score, and at least five years of follow-up or a BC recurrence were included in the study. All patients received either Tamoxifen or an aromatase inhibitor. None of the patients received adjuvant systemic chemotherapy.

RESULTS

There was no significant difference in the risk of recurrence in similar risk categories (very low risk, low risk, and high risk) between the average Modified Magee score and ODX recurrence score with the chi-square test of independence (p > 0.05) or log-rank test (p > 0.05). Using the RoMMa, we estimate that at least 17% of individuals can safely avoid ODX testing.

CONCLUSION

Our study further reinforces that BC patients can be confidently stratified into lower and higher-risk recurrence groups using the Magee equations^TM. The RoMMa can be helpful in the initial clinical risk-assessment and risk-stratification of BC patients, providing increased opportunities for cost savings in the health care system, and for clinical risk-assessment and risk-stratification in less-developed geographies where multigene testing might not be available.

The Evolution of Ki-67 and Breast Carcinoma: Past Observations, Present Directions, and Future Considerations

The 1983 discovery of a mouse monoclonal antibody-the Ki-67 antibody-that recognized a nuclear antigen present only in proliferating cells represented a seminal discovery for the pathologic assessment of cellular proliferation in breast cancer and other solid tumors. Cellular proliferation is a central determinant of prognosis and response to cytotoxic chemotherapy in patients with breast cancer, and since the discovery of the Ki-67 antibody, Ki-67 has evolved as an important biomarker with both prognostic and predictive potential in breast cancer. Although there is universal recognition among the international guideline recommendations of the value of Ki-67 in breast cancer, recommendations for the actual use of Ki-67 assays in the prognostic and predictive evaluation of breast cancer remain mixed, primarily due to the lack of assay standardization and inconsistent inter-observer and inter-laboratory reproducibility. The treatment of high-risk ER-positive/human epidermal growth factor receptor-2 (HER2) negative breast cancer with the recently FDA-approved drug abemaciclib relies on a quantitative assessment of Ki-67 expression in the treatment decision algorithm. This further reinforces the urgent need for standardization of Ki-67 antibody selection and staining interpretation, which will hopefully lead to multidisciplinary consensus on the use of Ki-67 as a prognostic and predictive marker in breast cancer. The goals of this review are to highlight the historical evolution of Ki-67 in breast cancer, summarize the present literature on Ki-67 in breast cancer, and discuss the evolving literature on the use of Ki-67 as a companion diagnostic biomarker in breast cancer, with consideration for the necessary changes required across pathology practices to help increase the reliability and widespread adoption of Ki-67 as a prognostic and predictive marker for breast cancer in clinical practice.

HER2-low breast cancers: incidence, HER2 staining patterns, clinicopathologic features, MammaPrint and BluePrint genomic profiles

Recently, clinical trials have demonstrated promising efficacy for novel HER2-targeted therapies in HER2-low breast cancers, raising the prospect of including a HER2-low category (immunohistochemical [IHC] score of 1+, or 2+ with non-amplified in-situ hybridization [ISH]) in the HER2 evaluation of breast cancers. In order to better understand this newly-proposed HER2 category, we investigated the incidence, HER2 staining patterns, clinicopathologic features, and genomic profile of HER2-low breast cancers. HER2-stained slides of 281 consecutive breast cancers were re-reviewed and the clinicopathologic information, MammaPrint, and BluePrint results of these cases were retrospectively analyzed. HER2-low breast cancers were identified in 31% of cases and were more common in estrogen receptor (ER)-positive than ER-negative breast cancers (33.6% vs 15%, p = 0.017). HER2-low cancers were generally clinical stages I-II (79%), ER-positive (93.1%), had homogenous HER2 staining (59.2%), HER2 IHC score of 1+ (87.4%), ductal phenotype (81.6%), histologic grades of 1 or 2 (94.2%) and luminal molecular subtypes (94.3%). Three HER2-low patients received neoadjuvant chemotherapy and none of them achieved pathologic complete response. When compared to HER2-negative (IHC of 0+) and HER2-positive (IHC of 3+ or IHC of 2+ with amplified ISH) cancers, HER2-low breast cancers had significantly lower Ki-67 (p = 0.03 and p < 0.01, respectively) and higher ER positivity (p = 0.01 and p = 0.03, respectively). HER2-low breast cancers were less likely to be basal molecular subtype when compared to HER2-negative cancers (p < 0.01) and were less likely to have a HER2 molecular subtype when compared to HER2-positive cancers (p < 0.01). When adjusted for ER status, there was no significant difference on all the examined variables between HER2-low and HER2-negative groups. Our study provides valuable baseline characteristics of HER2-low breast cancers deriving from consecutive, real-world cases with a consensus confirmation of HER2 status, and would help to increase our understanding of this newly-proposed HER2 category in breast cancers.

HER2-low breast cancers: Current insights and future directions

In light of the significant clinical benefits of novel HER2-targeting antibody-drug conjugates in advanced HER2-low expressing breast cancers in recent phases I and III clinical trials, particularly trastuzumab-deruxtecan (T-Dxd), the new "HER2-low" category in breast cancers (breast cancer with a HER2 IHC score of 1+, or 2+ without gene amplification) has gained increasing attention. In the past year, "HER2-low" breast cancers have been under active investigation by both oncologists and pathologists. In this current review, we update the recent cutting-edge research on HER2-low breast cancers, with a focus on the biology of HER2-low breast cancers, the issues on the identification of HER2-low breast cancers by immunohistochemistry in current practice of pathology, and the future directions in this emerging category in breast cancers.

HER2-Low Breast Cancers

OBJECTIVES

Recent clinical trials have demonstrated significant clinical benefits from novel therapeutic compounds in breast cancer patient with human epidermal growth factor receptor 2 (HER2) immunohistochemical (IHC) score of 1+ or 2+ and negative in situ hybridization (ISH) result. A new concept of "HER2-low" breast cancer has been proposed and applied in the recent and ongoing clinical trials. In this article, we review the literature on the topic of HER2-low breast cancer.

METHODS

A literature search in PubMed was performed using key words related to HER2-low breast cancer. Major relevant studies that were presented in international breast cancer conferences were also included.

RESULTS

HER2-low breast cancer is currently defined as breast cancer with HER2 IHC score of 1+ or 2+ and negative ISH result. It likely represents a group of tumors with significant biological heterogeneity. Reports of clinical activity using the next generation of HER2-targeting antibody-drug conjugates in HER2-low breast cancers suggest that some strategies of targeting HER2 might be effective in this patient population while raising considerable concerns over limitations in our current testing methodologies and our ability to accurately identify such patients.

CONCLUSIONS

The promising efficacy of novel HER2-targeted therapy in advanced HER2-low breast cancers has raised the possibility for changing the clinical interpretation of HER2 status in breast cancer to include a HER2-low category; however, the definition of HER2-low breast cancer, the corresponding reliable and accurate quantitative HER2 testing methodology, and the biology of HER2-low breast cancer remain poorly defined.

Abstract P4-05-09: Clinicopathologic characteristics and molecular profiling of HER2-low breast cancer: A single academic institution experience

Objectives: Recently-published phase I clinical trials have demonstrated promising efficacy of novel HER2-targeted therapy in advanced breast cancers with a HER2 immunohistochemistry (IHC) score of 1+, or 2+ with a non-amplified in-situ hybridization (ISH). This has raised the possibility for changing the categories for clinical interpretation of HER2 in breast cancers into: 1) HER2-negative (HER2 IHC score of 0+), 2) HER2-low (IHC score of 1+, or 2+ with a non-amplified ISH), and 3) HER2-positive (HER2 IHC score of 3+ and IHC score of 2+ with amplified ISH). Earlier studies on low HER2-expressing breast cancers focused on differences between HER2 2+ with negative ISH and HER2 0/1+. The aims of this study are to investigate the clinical, pathologic and molecular features of HER2-low breast cancers, in comparison to HER2-negative breast cancers. Methods: 281 breast cancers with HER2 IHC were diagnosed between 04/2020 and 12/2020 at our institution, including 164 HER2-negative, 87 HER2-low, and 30 HER2-positve cases. The clinicopathologic information and molecular subtyping (Agendia BluePrint) results of HER2-low breast cancers were retrospectively collected, and compared to those of HER2-negative cases. A p-value of &lt; 0.05 was considered statistically significant. Results: HER2-low breast cancers accounted for 31% (87/281) of breast cancers in our study population. The majority of these HER2-low cases were clinical stage I-II, with 6 cases (6.9%) being stage IV. Most of the HER2-low cancers had a HER2 IHC score of 1+ (87%, 76/87), a ductal phenotype (82%, 71/87), histologic grades of 1 or 2 (94%, 82/87), were ER positive (94%, 81/86), PR positive (86%, 74/86), and had luminal molecular subtypes (96%, 83/87). Four patients received neoadjuvant chemotherapy and none of them achieved pathologic complete response. Compared to HER2-negative cancers, HER2-low breast cancers showed a lower Ki-67 (p&lt;0.05), a higher ER positivity (p&lt;0.05), a higher pathologic stage (p&lt;0.05), and were more likely to be of the luminal molecular subtype (p&lt;0.05). There was no significant difference in age, tumor size, histologic type, histologic grade, presence of lymphovascular invasion, PR status, or pathologic nodal stage (Table 1). Conclusions: HER-2 low breast cancers represent a heterogeneous group, and the majority are lower grade, early-stage, hormonal receptor positive, have a HER2 IHC score of 1+, and have a luminal molecular phenotype. This study provides the baseline clinicopathologic and molecular features of HER2-low breast cancers. Additional studies are needed to further elucidate the biology of HER2-low breast cancers.

Table 1. Comparison of clinicopathologic parameters and molecular subtypes between HER2-low and HER2-negative breast cancersHER2-Low (n=87)HER2-Negative (n=164)P valueAge (year)66.6264.380.22Tumor size (mm)21.4919.290.49Histologic typeDuctal711390.57Lobular1524Mixed11Histologic grade143640.156239813519pT Stage142880.0452817362Unknown2735PN stage036760.351613210300Unknown2353ER positivity94.2 % (81/86)82.9% (136/64)0.01PR positivity86% (74/86)76.8% (126/164)0.09Ki-67 (%)12.8118.290.03Molecular subtypeLuminal A571050.003Luminal B2630HER210Basal328

Citation Format: Huina Zhang, Hani Katerji, Bradley M Turner, David G Hicks. Clinicopathologic characteristics and molecular profiling of HER2-low breast cancer: A single academic institution experience [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-05-09.

Abstract P5-06-13: Second-harmonic generation imaging reveals neoadjuvant chemotherapy-induced changes in breast tumor collagen

Breast cancer is the most common invasive cancer in women, with most deaths attributed to metastases. Neoadjuvant chemotherapy (NACT) may be prescribed prior to surgical removal of the tumor for subsets of breast cancer patients but can have diverse undesired and off-target effects including increased appearance of the ‘tumor microenvironment of metastasis’ or TMEMs, image-based multicellular signatures which are prognostic of metastasis. In this study we explored whether NACT alters other image-based prognostic/predictive signatures, specifically second-harmonic generation (SHG) directionality, which is indicative of collagen fiber internal structure, as well as the disorganization in collagen fiber alignment. This was performed in paired biopsy/excision samples from 22 patients with HER2 overexpressing invasive ductal carcinoma as well as 22 patients with triple negative breast cancer (TNBC). We found that collagen fiber internal structure, measured using the SHG forward-to-backward-scattered ratio (F/B), is altered in the bulk of the tumor in both tumor types (p = 0.015 and 0.038, respectively), but not the adjacent tumor-stroma interface (p = 0.54 and 0.92, respectively), where F/B is prognostic of metastatic outcome. Overall disorganization in collagen fiber alignment was not significantly changed by NACT in HER2 overexpressing disease (p = 0.41) but was decreased in TNBC (p = 0.0051). These results suggest that NACT alters the collagenous extracellular matrix in diverse ways, with implications for the use of F/B and collagen fiber alignment as prognostic and predictive tools.

Citation Format: Edward Brown, Danielle Desa, Robert M Brown, Edward B Brown, Robert L Hill, Bradley M Turner. Second-harmonic generation imaging reveals neoadjuvant chemotherapy-induced changes in breast tumor collagen [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-06-13.

Abstract P4-06-03: Clinical-risk assessment of ER positive, Her2 negative breast cancer patients: Correlation between the average modified magee score and mammaprint

Background: MammaPrint (MP) is an FDA approved early breast cancer prognostic genomic assay that examines the expression levels of 70 genes and classifies clinically high-risk patients with early-stage breast cancer into low or high risk of distant metastasis. Current ASCO guidelines do not support using MP testing in clinically low-risk patients. Historically, assessing a patient’s clinical risk for breast cancer recurrence has relied on a subjective evaluation of histologic factors, immunohistochemical features, and clinical characteristics. Genomic assay testing provides more objective prognostic and predictive information than those more traditional methods; however, several studies have shown that statistical models using standard histologic variables can give valuable prognostic information, and might be used as an alternative approach to genomic assays for clinical risk-assessment and risk-stratification, particularly in lower risk breast cancer patients, potentially resulting in significant cost savings for health care systems. One of these statistical models, the average Modified Magee equation, has been shown to be prognostic for a low risk of recurrence in ER positive Her2 negative breast cancer patients who have an average Modified Magee score (aMMs) of ≤ 12. The aMMs has been shown to correlate well with the Oncotype DX recurrence score; however, there is limited data on the correlation between the aMMs and MP. In this study, we evaluated the concordance between the aMMs and the MP index (MPI). Methods: 222 consecutive patients with a new diagnosis of hormone receptor positive Her-2 negative breast cancer at the University of Rochester between April 2020 and December 2020 were sent for MP testing. The aMMs was determined for each patient based on the estrogen receptor status, progesterone receptor status, HER-2 status, Ki-67 proliferation index, Nottingham score, and tumor size. Based on the previous literature, patients were risk-stratified by the aMMs into three groups: 1) low risk (aMMs ≤ 12; n = 75); 2) low - intermediate risk (aMMs &gt;12 and ≤ 18; n = 96); and, 3) high risk (aMMs &gt;18, n = 51). Based on the previous literature, patients were risk-stratified by the MPI into two groups: 1) low risk (MPI 0 to +1); and, 2) high risk (MPI -1 to 0). The correlation between the aMMs and the MPI was evaluated using the Pearson correlation coefficient. Results: The aMMs showed a negative correlation (r= -0.55) with the MPI, consistent with a lower risk aMMs more likely being associated with a lower risk MPI. 92% of patients with an aMMs ≤ 12 (very low risk) were classified as low risk by MP. 72% of patients with an aMMs &gt; 12 and ≤ 18 (low - intermediate risk) were classified as low risk by MP. 47% of patients with an aMMs &gt; 18 (high risk) were classified as high risk by MP (Table 1). All patients with an aMMs ≥ 24.7 (n=8) were classified as high risk by MP. Conclusion: Our study suggests that hormone receptor positive, Her-2 negative breast cancer patients with a lower risk aMMs are likely to have a lower MPI, suggesting that these patients have a decreased risk for breast cancer recurrence. As the aMMs approaches higher risk, the concordance with the MPI decreases; however 100% of patients with an aMMs ≥ 24.7 were classified as high risk by MP. The aMMs can be helpful in clinical risk-assessment prior to making a decision about sending a patient specimen out for MP testing. Additional studies are warranted.

Table 1.Risk of recurrence using the average Modified Magee score (aMMs) and the MammaPrint (MP) IndexaMMs Risk-stratification categoryMP Low risk n (%)MP High risk n (%)Very low (aMMs ≤ 12)69 (92%)6 (8%)Low - Intermediate (aMMs &gt; 12 and ≤ 18)69 (72%)27 (28%)High (aMMs &gt;18)27 (53%)24 (47%)

Citation Format: Hani Katerji, Huina Zhang, David Hicks, Bradley M Turner. Clinical-risk assessment of ER positive, Her2 negative breast cancer patients: Correlation between the average modified magee score and mammaprint [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-06-03.

Abstract P4-06-07: Clinical risk-assessment, risk-stratification, and outcomes of ER positive, HER2 negative breast cancer patients using the Rochester modified Magee algorithm (RoMMA)

INTRODUCTION: In 2013, Klein and Dabbs et al. published three linear regression equations (the new Magee equations) using different combinations of standard histopathologic variables. In 2015, our group published a modification of the new Magee equations. Based on this modification, we published an algorithmic approach using an average Modified Magee equation. This algorithmic approach supported reflex Oncotype DX (ODX) testing based on several cutoff points using an average Modified Magee score. In 2019, we validated this algorithmic approach as the Rochester Modified Magee Algorithm (RoMMA) in a multi-institutional study, with outcome data in 247 patients, suggesting that ER positive breast cancer patients with an average Modified Magee score of ≤ 12 had a low risk of breast cancer recurrence. There has been limited published outcome data on the Magee equation since that 2019 study. We have further refined our risk-stratification approach, with additional outcome data in 416 ER positive breast cancer patients. METHODS: 416 patients with an ODX recurrence score who had at least five years of follow-up data or a breast cancer recurrence were included in the final outcome analysis (2008-2017). All patients received either Tamoxifen or an aromatase inhibitor. None of the patients received adjuvant systemic chemotherapy. The average Modified Magee score was calculated and patients were stratified into four risk-stratification categories: 1) very low, 2) low ≤ 50 years of age, 3) low &gt; 50 years of age, and 4) high. We compared these four risk-stratification categories, with outcomes, between the average Modified Magee score and the ODX recurrence score. A p-value of &lt; 0.05 was considered statistically significant. RESULTS: 27/416 (6.5%) patients had a recurrence of breast cancer. When comparing the same risk category groups, there was no significant difference between the average Modified Magee score and the ODX recurrence score (Table 1). CONCLUSION: Our study further reinforces that breast cancer patients can be confidently stratified into low and high risk recurrence groups using the average Modified Magee score. The average Modified Magee score may be an alternative to ODX for clinical risk-assessment and risk-stratification, particularly in lower risk patients, offering breast cancer patients increased access to clinical risk-assessment and risk-stratification, both domestically and internationally, with a potential significant cost savings for health care systems. A large prospective evaluation, similar to the studies done by ODX, using multi-institutional data or data from studies like the NSABP trial B-14 and the NSABP trial B-20, is necessary.

Table 1.Risk-stratification categories and outcomes using the average Modified Magee score (aMMs) and the Oncotype DX recurrence score (ODXRS)RECURRENCENO RECURRENCEP-VALUEVERY LOW (N)aMMs ≤ 12 (76)1 (1.3)75 (98.7)0.65ODXRS &lt; 11 (108)4 (3.7)104 (96.3)LOW ≤ 50 years of age (N)aMMs &gt; 12, ≤ 18 (50)3 (6.0)47 (94.0)1.0ODXRS 11 - 15 (32)1 (3.1)31 (96.9)LOW &gt;50 years of age (N)aMMs &gt; 12, ≤ 18 (153)8 (5.2)145 (94.8)0.52ODXRS 11 - 25 (214)16 (7.5)198 (92.5)HIGH (N)aMMs &gt; 18 (137)15 (10.9)122 (89.1)1.0ODXRS ≥ 16 - 25 (33)* and ODXRS &gt; 25 (29)**6 (9.7)56 (90.3)* Patients ≤ 50 years of age with an ODXRS of ≥16 - 25. ** All patients with an ODXRS of &gt; 25

Citation Format: Numbereye Numbere, Ioana Moisini, Ajay Dhakal, Kristin Skinner, Michelle Shayne, Mary Ann Gimenez Sanders, Huina Zhang, David Hicks, Bradley M Turner. Clinical risk-assessment, risk-stratification, and outcomes of ER positive, HER2 negative breast cancer patients using the Rochester modified Magee algorithm (RoMMA) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-06-07.

The relationship of myometrial histopathology (metropathy) to myometrial dysfunction and clinical manifestations

Myometrial morphology and myometrial physiology have been considered to be separate entities; however, observations of myometrial morphology and associated dysfunctions suggest a relationship between myometrial morphology and myometrial physiology that deserves further exploration. Although myometrial electrical activity can be monitored by electrohysterogram, the association of increased myometrial contractions with an increase in electrical activity (due to an increase in gap junctions) is typically not evaluated. Although the association of increased myometrial contractions with increase in pain can be monitored by tocometry and intrauterine pressure catheters, respectively, this is generally not done in the non-pregnant uteri. Although standard morphologic evaluations routinely include evaluation with special stains and immunohistochemistry in other organ systems, such as skeletal and cardiac muscle, these evaluations are not standard or routine for myometrium in hysterectomies. The purpose of this review is to discuss non-neoplastic myometrial histology, with consideration of the potential value of using tools to measure variations in myometrial physiology, in order to reliably correlate myometrial histology with myometrial function (and dysfunction).

Interobserver Agreement in the Diagnosis of Anal Dysplasia: Comparison Between Gastrointestinal and Gynaecologic Pathologists and Utility of Consensus Conferences

INTRODUCTION

Management of anal dysplasia relies on the accurate diagnosis of anal biopsy specimens. As institutions move toward subspecialty signout (SSSO), decisions must be made regarding whether to assign anal biopsies to the gastrointestinal (GI) or gynaecologic (GYN) pathology service.

MATERIALS AND METHODS

We identified 200 archival tissue biopsies of anal mucosa and circulated them among three GI pathologists and three GYN pathologists. Each pathologist separately scored each biopsy as normal, atypical, LSIL, or HSIL. Every case that was called HSIL by at least one pathologist was stained with p16 immunostain and a "gold standard" interpretation of whether a case represented HSIL was made.

RESULTS

The GI pathologists agreed on 97 (49%) cases prior to consensus; the GYN pathologists agreed on 33 (17%). The sensitivities of the 3 GI pathologists in detecting HSIL against the "gold standard" were 47%, 100%, and 21%, and for the GYN pathologists the sensitivities were 74%, 89%, and 84%; the sensitivities of both the GI and GYN consensus diagnoses were 74% each. The specificities of the 3 GI pathologists in detecting HSIL were 99%, 90%, and 100%, and for the GYN pathologists the specificities were 99%, 92%, and 91%; the specificities of both the GI and GYN consensus diagnoses were 100%.

CONCLUSIONS

A mild to moderate degree of interobserver variability exists in the diagnosis of anal dysplasia among pathologists. Our study does indicate the utility of some form of consensus conference, as overall agreement among GI pathologists and among GYN pathologists improved following in-person consensus.

Significance of HER2 in Microinvasive Breast Carcinoma

OBJECTIVES

We compared the clinicopathologic features, clinical management, and outcomes of human epidermal growth factor receptor 2 (HER2)-expressing and nonexpressing microinvasive breast carcinomas (MiBC) to explore the significance of HER2 in MiBC.

METHODS

Clinicopathologic and follow-up information of cases with final diagnosis of MiBC with known HER2 status between 2007 and 2019 were analyzed.

RESULTS

Nineteen (41.3%) HER2-positive (HER2+) and 27 (58.7%) HER2-negative (HER2-) MiBCs were identified. HER2 positivity was likely to be associated with high nuclear grade, presence of tumor-infiltrating lymphocytes, hormonal receptor negativity, and increased Ki-67 in both microinvasive and associated in situ carcinomas. Nodal metastases were found in 2 ER+/HER2- cases (5.3%). One HER2+ case was found to have isolated tumor cells in the axillary node. The majority of patients with HER2+ MiBCs (76.5%) did not receive HER2-targeted therapy. All patients with available follow-up were alive without recurrence or distant metastasis, with a median follow-up of 38 months.

CONCLUSIONS

Similar to the larger size of invasive breast carcinomas, HER2 positivity is associated with high-grade morphologic features in MiBCs. However, HER2 overexpression in MiBCs does not appear to be associated with nodal metastasis or worse outcome in our study cohort. The role of HER2-targeted therapy in this clinical setting merits additional study.

Reproducibility of scoring criteria for HER2 immunohistochemistry in endometrial serous carcinoma: a multi-institutional interobserver agreement study

Targeted anti-human epidermal growth factor receptor 2 (HER2) therapy has recently been proven to improve progression-free and overall survival of patients with advanced stage or recurrent endometrial serous carcinoma. To date, no specific pathology HER2 testing or scoring guidelines exist for endometrial cancer. However, based on evidence from the recent successful clinical trial and comprehensive pre-trial pathologic studies, a new set of HER2 scoring criteria have been proposed for endometrial serous carcinoma-distinct from the existing breast and gastric cancer-specific criteria. We present the first study assessing interobserver agreement of HER2 scores using the proposed serous endometrial cancer-specific scoring system. A digitally scanned set of 40 HER2-immunostained slides of endometrial serous carcinoma were sent to seven gynecologic pathologists, who independently assigned HER2 scores for each slide following a brief tutorial. Follow-up fluorescent in situ hybridization (FISH) for HER2 gene amplification was performed on cases with interobserver disagreement when a 2+ HER2 score was assigned by at least one observer. Complete agreement of HER2 scores among all 7 observers was achieved on 15 cases, and all but one case had an agreement by at least 4 observers. The overall agreement was 72.3% (kappa 0.60), 77.5% (kappa 0.65), and 83.3% (kappa 0.65), using four (0 to 3+ ), three (0/1+ , 2+ , 3+ ), or two (0/1+ , 2/3+ ) HER2 scoring categories, respectively. Based on the combination of HER2 immunostaining scores and FISH, the interobserver disagreement may have potentially resulted in a clinically significant difference in HER2 status only in three tumors. We conclude, that the proposed serous endometrial cancer-specific HER2 scoring criteria are reproducible among gynecologic pathologists with moderate to substantial interobserver agreement rates comparable to those of previously reported in breast and gastric carcinomas. Our findings significantly strengthen the foundation for establishing endometrial cancer-specific HER2 scoring guidelines in the future.

L1CAM Expression in Recurrent Estrogen Positive/HER2 Negative Breast Cancer: A Novel Biomarker Worth Considering

We investigate L1 cell adhesion molecule (L1CAM) expression in estrogen receptor (ER)-positive/human epidermal growth factor receptor (HER2)-negative breast carcinomas. The finding of a potential correlation between high L1CAM expression and recurrent/metastatic disease in luminal A and B breast carcinomas may be helpful for risk stratification and open opportunities for targeted therapies. 304 cases comprising 152 cases of ER-positive, progesterone receptor (PR)-positive/negative, and HER2-negative recurrent/metastatic breast carcinomas and 152 nonrecurrent controls were included. ER, PR, HER-2, Ki-67 status, Nottingham grade, tumor size, tumor stage, number of foci, lymph node status, lymphovascular invasion, phenotype, laterality, age at diagnosis and first distant or local recurrence were recorded. L1CAM positive cases showed increased specificity for recurrence and these patients were significantly younger than L1CAM negative ones. Compared with L1CAM negative recurrent cases, L1CAM positive ones had a noticeably higher Ki-67, tended to be larger and recurred sooner. All L1CAM positive recurrent/metastatic cases were of the luminal B subtype compared with 67.3% of the L1CAM negative cases. L1CAM is highly specific for recurrence in a subset of breast cancer patients and may be associated with more aggressive behavior, particularly in luminal B breast cancers with higher Ki-67 expression. Further investigation about the prognostic value of L1CAM is warranted.

The pathogenesis of abnormal uterine bleeding in myopathic uteri

It has been suggested that impaired venous drainage and endometrial vascular ectasia (EMVE), secondary to increased intramural pressure, explains abnormal bleeding in fibroid uteri. Striking EMVE with extravasated red blood cells (ecchymosis) has also been seen in uteri with grossly obvious myometrial hyperplasia (MMH), suggesting that increased intramural pressure can cause EMVE in the absence of fibroids. EMVE with MMH may explain the century old association of clinically enlarged uteri with abnormal bleeding, and this same mechanism may be operative in myopathic uteri with grossly obvious adenomyosis. EMVE with associated thrombosis, ecchymosis, and/or stromal breakdown is commonly seen in random sections of hysterectomies for bleeding. EMVE may also be associated with endothelial hyperplasia, consistent with a reaction to endothelial injury due to impaired venous drainage. This further supports the theory that EMVE bleeds when thrombosis occurs, due to Virchow's Triad (stasis, endothelial injury, and hypercoagulability). EMVE may be "the lesion for which surgery was performed" in hysterectomies with otherwise unexplained bleeding.

Abstract PS6-24: Are we missing something? Increased recurrence rates in patients with an oncotype DX score &lt; 26 and a modified magee score &gt; 18: A multi-institutional study

INTRODUCTION: Oncotype DX® (ODX) is a multigene assay estimating risk of distant recurrence and chemotherapy benefit in estrogen receptor (ER) positive breast cancer patients. Cost ($4,620.00) impedes its adoption in poorer countries, and the cost is unnecessary in certain patients. TAILORx results suggest that adjuvant endocrine therapy and chemoendocrine therapy had similar efficacy in women with hormone-positive, HER2-negative, node-negative invasive breast carcinomas with an ODX recurrence score &lt; 26. Bhargava et al. and Turner et al. have suggested that a Magee scoreTM or a modified Magee score, respectively, of &lt; 18 will identify patients who are highly likely to have an ODX recurrence score of &lt; 26, and we previously presented data at SABCS 2019 (Abstract P3-07-06) that there is no significant difference in recurrence rate between patients with a modified Magee score of ≤ 18 and patients with an ODX recurrence score &lt; 26 (in preparation for publication). We now present additional recurrence data on patients with a modified Magee score of &gt; 18. METHODS: A total of 301 consecutive patients with ER+ invasive breast cancer from the University of Rochester and the University of Louisville were included in this study, with a mean of 6.6 years of follow-up. All patients had at least 5 years of follow-up (range 5-11 years) except for seven patients , who had a breast cancer recurrence prior to five years. Information on ER, PR, HER-2, Ki-67, Nottingham score , and tumor size were extracted from the pathology report in order to calculate the modified Magee score. Information, on hormone therapy, chemotherapy, radiation therapy, recurrence status, and mortality were extracted from the medical record. For all results, a p-value of &lt; 0.05 was considered significant. RESULTS: 117/301 (39%) patients had a modified Magee score of &gt; 18. The recuurence rate for patients with a modified Magee score &gt; 18 was 11.1%. There was no significant difference in recurrence rate between patients with both a modified Magee score &gt; 18 and ODX recurrence score &lt; 26 compared to patients with both a modified Magee score &gt;18 and ODX recurrence score ≥ 26 (p = 0.547, Table 1). CONCLUSIONS: Patients with a modified Magee score &gt; 18 may be at increased risk for breast cancer recurrence, even if the ODX recurrence score is &lt; 26. Additional studies are necessary to further evaluate these findings.

Table 1: Modified Magee score &gt; 18, Oncotype DX recurrence score (ODXRS), and outcomeRecurrenceNo recurrenceModified Magee score &gt; 18 and ODXRS &lt; 26870Modified Magee score &gt; 18 and ODXRS ≥ 26633

Citation Format: Bradley M Turner, Mary Ann Gimenez-Sanders, Ioana Moisini, Huina Zhang, Xi Wang, Linda Schiffhauer, Hani Katerji, Kristin Skinner, Jessica Gooch, Michelle Shayne, Marilyn Ling, Carla Falkson, David Hicks. Are we missing something? Increased recurrence rates in patients with an oncotype DX score &lt; 26 and a modified magee score &gt; 18: A multi-institutional study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-24.

Abstract PS6-18: Are we missing something? Ki-67 evaluation is important in African American women with an oncotype DX score&lt; 26: A multi-institutional study

INTRODUCTION: The literature suggests that there is no difference in the Oncotype DX® (ODX) recurrence score between African American (AA) women and Caucasian (CA) women; however, an analysis of clinical outcomes in participants enrolled in the TAILORx trial found that AA women had worse clinical outcomes than CA women, despite similar ODX recurrence scores. The TAILORx trial suggested that chemoendocrine therapy may not be necessary in women with hormone-positive, HER2-negative, node-negative invasive breast carcinomas with an ODX recurrence score &lt; 26. We examine Ki-67 (a marker of tumor proliferation) in relation to an ODX recurrence score of 26 in AA and CA women from two seperate institutions. METHODS: A total of 851 consecutive cases of AA (n = 78) and CA women (n = 773) with ER+ invasive breast cancer and available ODX recurrence scores from the University of Rochester and the University of Louisville were included in this study. For all results, a p-value of &lt; 0.05 was considered significant. RESULTS: Consistent with the previous literatuere, there was no significant difference between the average ODX recurrence score of AA and CA women (p = 0.44, Table 1), and we found no significant difference in average ER, PR, Nottingham score, or tumor size between AA and CA patients; however, the Ki-67 was significantly higher in AA patients with an ODX recurrence score &lt; 26 compared to CA patients with and ODX recurrence score &lt; 26 (p = 0.002, Table 2). This significant difference in Ki-67 was not evident with an ODX recurrence score ≥ 26 (p = 0.98, Table 2). CONCLUSIONS: Our preliminary results suggest that compared to CA women, AA patients are more likely to have a higher Ki-67 if the ODX recurrence score is &lt; 26. AA breast cancer patients with an ODX &lt; 26 are at increased risk for recurrence compared to CA women with an ODX &lt; 26. Ki-67 evaluation is not routinely done as part of the breast cancer workup in many institutions. Ki-67 evaluation may be helpful to help guide treatments decisions in AA patients with and ODX &lt; 26. Additional investigation is warranted.

Table 1: Oncotype DX and histopathologic variables for African American and Caucasian womenODXRS* (mean)ER** (mean)PR** (mean)NS***(mean)Ki-67 (mean)****Tumor size (mean)ODXRS &lt; 26 (n) ODXRS ≥ 26 (n)ALL17.6255.3168.96.016.42.2713138AA18.3250.7175.96.321.42.26315CA17.5255.8168.26.015.92.2650123*Oncotype DX recurrence score** modified H-score*** Nottingham score****n = KI-67 available for 777 total patients (650 with ODXRS &lt; 26 and 127 with ODXRS ≥ 26); KI-67 available for 71 AA patients (51 with ODXRS &lt; 26 and 14 with ODXRS ≥ 26); KI-67 available for 706 CA patients (593 with ODXRS &lt; 26 and 113 with ODXRS ≥ 26)

Table 2: Oncotype DX &lt; 26 and ≥ 26 and associated histopathologic variables for African American and Caucasian womenODXRS* (mean)ER** (mean)PR** (mean)NS*** (mean)Ki-67 (mean)****Tumor size (mean)ODXRS &lt; 2614.5260.5189.15.813.72.2AA15.4262.8200.76.019.22.3CA14.4260.3188.05.813.12.2ODX ≥ 2633.8228.464.47.330.52.1AA30.3199.871.97.730.41.6CA34.2231.963.57.330.52.2*Oncotype DX recurrence score** modified H-score*** Nottingham score****n = KI-67 available for 777 total patients (650 with ODXRS &lt; 26 and 127 with ODXRS ≥ 26); KI-67 available for 71 AA patients (51 with ODXRS &lt; 26 and 14 with ODXRS ≥ 26); KI-67 available for 706 CA patients (593 with ODXRS &lt; 26 and 113 with ODXRS ≥ 26)

Citation Format: Bradley M Turner, Mary Ann Gimenez-Sanders, Huina Zhang, Ioana Moisini, Xi Wang, Linda Schiffhauer, Hani Katerji, Kristin Skinner, Jessica Gooch, Michelle Shayne, Marilyn Ling, Carla Falkson, David Hicks. Are we missing something? Ki-67 evaluation is important in African American women with an oncotype DX score&lt; 26: A multi-institutional study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-18.

Intratumoral heterogeneity of second-harmonic generation scattering from tumor collagen and its effects on metastatic risk prediction

Background

Metastases are the leading cause of breast cancer-related deaths. The tumor microenvironment impacts cancer progression and metastatic ability. Fibrillar collagen, a major extracellular matrix component, can be studied using the light scattering phenomenon known as second-harmonic generation (SHG). The ratio of forward- to backward-scattered SHG photons (F/B) is sensitive to collagen fiber internal structure and has been shown to be an independent prognostic indicator of metastasis-free survival time (MFS). Here we assess the effects of heterogeneity in the tumor matrix on the possible use of F/B as a prognostic tool.

Methods

SHG imaging was performed on sectioned primary tumor excisions from 95 untreated, estrogen receptor-positive, lymph node negative invasive ductal carcinoma patients. We identified two distinct regions whose collagen displayed different average F/B values, indicative of spatial heterogeneity: the cellular tumor bulk and surrounding tumor-stroma interface. To evaluate the impact of heterogeneity on F/B’s prognostic ability, we performed SHG imaging in the tumor bulk and tumor-stroma interface, calculated a 21-gene recurrence score (surrogate for OncotypeDX®, or S-ODX) for each patient and evaluated their combined prognostic ability.

Results

We found that F/B measured in tumor-stroma interface, but not tumor bulk, is prognostic of MFS using three methods to select pixels for analysis: an intensity threshold selected by a blinded observer, a histogram-based thresholding method, and an adaptive thresholding method. Using both regression trees and Random Survival Forests for MFS outcome, we obtained data-driven prediction rules that show F/B from tumor-stroma interface, but not tumor bulk, and S-ODX both contribute to predicting MFS in this patient cohort. We also separated patients into low-intermediate (S-ODX < 26) and high risk (S-ODX ≥26) groups. In the low-intermediate risk group, comprised of patients not typically recommended for adjuvant chemotherapy, we find that F/B from the tumor-stroma interface is prognostic of MFS and can identify a patient cohort with poor outcomes.

Conclusions

These data demonstrate that intratumoral heterogeneity in F/B values can play an important role in its possible use as a prognostic marker, and that F/B from tumor-stroma interface of primary tumor excisions may provide useful information to stratify patients by metastatic risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07713-4.

Applying the New Guidelines of HER2 Testing in Breast Cancer

PURPOSE OF REVIEW

The human epidermal growth factor receptor 2 (HER2) is an important prognostic and predictive biomarker in the breast cancer. The American Society of Clinical Oncology/College of American Pathology (ASCO/CAP) has published HER2 testing guidelines in breast cancer. We herein reviewed the HER2 testing guidelines in breast cancer with a focus on the application of the current guidelines.

RECENT FINDINGS

The continual investigation of HER2 testing in breast cancer has resulted in updates in the HER2 testing guidelines. The current guidelines focus on the uncommon clinical scenarios and emphasize the coordination between immunohistochemistry and in situ hybridization results, in an effort to improve clarity and accuracy. The ASCO/CAP guidelines provide valuable recommendations to ensure the accurate evaluation of HER2 status in breast cancer patients through standardization. Additional studies, particularly those with long-term outcome data are still needed to validate the guideline recommendations, especially the uncommon cases.

Frequency, Clinicopathologic Characteristics, and Follow-up of HER2-Positive Nonpleomorphic Invasive Lobular Carcinoma of the Breast

OBJECTIVES

To investigate human epidermal growth factor receptor 2 (HER2)-positive nonpleomorphic invasive lobular carcinoma (ILC), which has rarely been addressed.

METHODS

Clinicopathologic characteristics and follow-up of HER2-positive nonpleomorphic ILCs were collected and compared to those of HER2-negative counterparts.

RESULTS

Twenty-one cases of HER2-positive nonpleomorphic ILCs were identified, 6.3% of the study population. Compared to HER2-negative nonpleomorphic ILC, patients with HER2 positivity were older (P < .05), likely to be hormonal receptor negative (P < .01), and had higher histologic grade and angiolymphatic invasion (P < .01). HER2 positivity in nonpleomorphic ILCs was associated with higher recurrence/metastasis with hazard ratio of 2.03 (P < .05). No patient who received neoadjuvant therapy achieved pathologic complete response, and HER2-targeted therapy tended to reduce recurrence/metastasis in patients with HER2-positive nonpleomorphic ILC.

CONCLUSIONS

Our results highlight the existence of HER2 positivity in nonpleomorphic ILCs and reinforce that HER2 is associated with worse prognosis in nonpleomorphic ILC.

Abstract P5-08-25: Body mass index and liver metastasis in women with invasive breast carcinoma

INTRODUCTION: Breast cancer is the most prevalent non-skin cancer in women worldwide. Women with metastatic breast cancer to the liver have poor outcomes compared to metastases to other sites, frequently develop resistance to available hormonal and chemotherapeutic agents, and have poor overall survival. Conflicting evidence exists regarding the association of body mass index (BMI) with progression free and overall survival in patients with metastatic breast cancer.

METHODS: A single institution retrospective study of women with breast cancer metastasis to the liver was conducted. The pathology reports and medical records from 2011 to 2017 were searched to identify cases with biopsy proven liver metastases. Several factors were considered including breast cancer histologic type and stage at diagnosis; estrogen receptor, progesterone receptor, and HER2-neu amplification status of the initially diagnosed breast cancer as well as the metastatic disease; patient age and ethnicity; BMI (kg/m2) at time of metastasis and at initial diagnosis; and, outcome to include survival after liver metastasis diagnosis.

RESULTS: In our population, the BMI ranged from 21.2 kg/m2 to 56.3 kg/m2 (mean 28.4 kg/m2). Eighteen patients (62%) were either overweight or obese. Twenty-one patients (72.4%) were deceased at the time of the study with an average survival of 659 days after liver metastasis diagnosis (Table 1). Patients with a BMI &gt; 30 (obese) had a significantly lower (p &lt;0.0005) mean survival than patients who were overweight (BMI 25.0 kg/m2 - 29.9 kg/m2). Patients who were overweight had a significantly lower mean survival than patients who had a normal BMI (18.5 kg/m2 -24.9 kg/m2). Five patients with liver metastases survived greater than 2000 days. The mean BMI of these five patients was 25.4 kg/m2. CONCLUSION: Obesity is a well-known cause of co-morbidities, and has been suggested to negatively impact the prognosis in breast cancer. In patients with liver metastases, our data suggests that an increased BMI is associated with decreased survival. This appears to be consistent in both ER positive and Her-2 positive patients (Table 1). This finding may be true regardless of the metastatic site. Further investigation on BMI and patients with metastatic disease to the liver and other organs are needed. We continue to collect data on patients with metastatic disease to the liver and other sites, including bone, to further validate our findings.

Table 1: Mean overall survival in patients with liver metastasisTotalER+ Liver MetastasisHER2+ Liver MetastasisBMI kg/m2N (%)Mean Survival (days)*N (%)Mean Survival (days)*N (%)Mean Survival (days)*Underweight (&lt;18.5)0NA0NA0NANormal (18.5-24.9)6 (28.6)923.85 (31.3)1085.42 (40)547.5Overweight (25.0-29.9)8 (38.1)753.54 (25)7080NAObese (&gt; 30)7 (33.3)3237 (43.7)3233 (60)315NA: not applicable*p-values &lt;0.0005

Citation Format: Cynthia Reyes Barron, Maricarmen Planas-Silva, David G Hicks, Bradley M Turner. Body mass index and liver metastasis in women with invasive breast carcinoma [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-08-25.

Abstract P3-07-06: ER+ patients with an average modified Magee score ≤ 18 have a low likelihood of breast cancer recurrence and a high likelihood of an Oncotype Dx® recurrence score &lt; 26

INTRODUCTION: The recent TAILORx results suggest that adjuvant endocrine therapy and chemoendocrine therapy had similar efficacy in women with hormone-positive, HER2-negative, node-negative invasive breast carcinomas with an Oncotype Dx® recurrence score &lt; 26. Oncotype Dx® is an expensive test (current list price of $4,620.00). Although the Oncotype Dx® test has gained widespread acceptance, cost may be an impediment to its adoption in certain areas of the world, and it may not be the most cost-effective or cost-efficient option in certain subsets of breast cancer patients. Based on a modification of the new Magee equations, we published an algorithmic approach in 283 ER+ cases using an average modified Magee equation (Turner BM, et al. Mod Pathol. 2015;28(7):921-31), and subsequently published a validation of this algorithmic approach in an additional 620 ER+ cases (Cancer Med. 2019 Jun 14. doi: 10.1002/cam4.2323. [Epub ahead of print]), supporting only reflex Oncotype Dx® testing for certain subsets of breast cancer patients. We now have recurrence data and at least five years of outcome data on 310 cases.

METHODS: A total of 310 cases with ER+ invasive breast cancer, all with Oncotype Dx® recurrence scores, were included in this study from the University of Rochester and the University of Louisville. The outcome analysis included all patients who had at least five years of follow-up data, and all patients who had a breast cancer recurrence. In order to calculate the average modified Magee score, information on the Nottingham score, ER, PR, Ki-67, HER-2, and tumor size was extracted from the pathology report.

RESULTS: 255/310 cases had an Oncotype Dx® &lt; 26, and 4% (10/255) of these cases were associated with a breast cancer recurrence. 187/310 cases had an average modified Magee score ≤ 18, and 184 of these 187 cases (98%) had an Oncotype Dx® recurrence score &lt; 26. Only 2% (n = 4) of these 184 cases were associated with a breast cancer recurrence. On average, the Nottingham score and Ki-67 were lower for cases with an average modified Magee score ≤ 18 compared to cases with an Oncotype Dx® recurrence score &lt; 26 (Table 1). On average, the modified ER and PR H-scores were higher for cases with an average modified Magee score ≤ 18 compared to cases with an Oncotype Dx® recurrence score &lt; 26 (Table 1).

CONCLUSION: If the average modified Magee score is ≤ 18, the patient has a low likelihood of recurrence, and the Oncotype Dx® recurrence score will likely be &lt; 26. Given the recent TAILORx findings, we suggest that patients with an average modified Magee score ≤ 18 not be sent out for Oncotype Dx® testing if an Oncotype Dx® recurrence score &lt; 26 is the basis on which the clinician will use to decide whether or not to give chemotherapy. The information needed to use the average modified Magee equation is already generated by many pathology laboratories during the initial assessment of breast cancer, and the Magee equations are free of charge (https://path.upmc.edu/onlineTools/mageeequations.html). Based on the Genomic Health 2017 Annual Report, our data suggests that not sending out cases with an average modified Magee score ≤ 18 would have resulted in a potential cost savings to the health-care system in 2018 of almost 300 million dollars.

Table 1: Average Nottingham score, modified ER H-score, modified PR H-score, and Ki-67, with number and percent recurrence for cases with an average modified Magee score ≤ 18 and cases with an Oncotype Dx® recurrence score &lt; 26AVERAGERecurrence Sore typeNNS**ER***PR***Ki-67Recurrence N (%)Average modified Magee score ≤ 18*1875.2262.3235.410.34 (2)Oncotype Dx® recurrence score &lt; 262555.5253.2192.613.610 (4)*98% (184/187) of patients with an average modified Magee score ≤ 18 had an Oncotype Dx® recurrence score &lt; 26**Nottingham score***modified H-score (Turner BM, et al. Mod Pathol. 2015;28(7):921-31)

Citation Format: Hasan Khatib, Mary Ann G Sanders, Andrea Breaux, Armen Soukiazian, Nyrie Soukiazian, David Hicks, Bradley M Turner. ER+ patients with an average modified Magee score ≤ 18 have a low likelihood of breast cancer recurrence and a high likelihood of an Oncotype Dx® recurrence score &lt; 26 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-07-06.

A Comparison of Hysterectomies for Bleeding With Hysterectomies for Pain

Objectives. We recently suggested that increased intramural pressure may often explain pain and/or bleeding. Hysterectomies for bleeding tend to have outward bulges and endometrial vascular ectasia, while hysterectomies for pain tend to have deflection of pressure inward by subserosal ridges, which promote inner myometrial elastosis (IME). Study design. We analyzed causes of increased intramural pressure in 58 hysterectomies for pain and/or bleeding, excluding clinically fibroid uteri and prolapsed uteri. Postfixation photographs were used to avoid missing grossly obvious myometrial hyperplasia (MMH). Results. The most common cause of increased intramural pressure was grossly obvious MMH in 40/58 cases (69%). Other causes included clinically occult myomas (3 cases), adenomyosis (6 cases), and multifactorial causes (7 cases). Hysterectomies for bleeding weighed more than hysterectomies for pain ( P = .035). Hysterectomies for pain had more IME than hysterectomies for bleeding ( P = .029). Conclusions. When subserosal ridges deflect pressure inward, bulky MMH may cause pelvic pain and IME, but when they do not, bulkier MMH in heavier uteri may lead to both outward bulges and abnormal bleeding from endometrial vascular ectasia.

Second-harmonic generation directionality is associated with neoadjuvant chemotherapy response in breast cancer core needle biopsies

Neoadjuvant chemotherapy (NACT) is routinely administered to subsets of breast cancer patients, including triple negative (TN) or human epidermal growth factor receptor 2-positive (HER2+) cancers. After NACT and subsequent surgical resection, 5% to 30% of patients have no residual invasive carcinoma, termed pathological complete response. Unfortunately, many patients experience little-to-no response after NACT and unnecessarily suffer its side effects. Methods are needed to predict an individual patient’s response to NACT. Core needle biopsies, taken before NACT, consist of tumor cells and the surrounding extracellular matrix. We performed second-harmonic generation (SHG) imaging of fibrillar collagen in core needle biopsy sections as a possible predictor of response to NACT. The ratio of forward-to-backward scattering (F/B) SHG was assessed in the “tumor bulk” and “tumor–host interface” in HER2+ and TN core needle biopsy sections. Patient response was classified post-treatment using the Residual Cancer Burden (RCB) score. In HER2+ biopsies, RCB class was associated with F/B derived from the tumor–stromal interface, but not tumor bulk. F/B was not associated with RCB class in TN biopsies. These findings suggest that F/B from needle biopsy sections may be a useful predictor of which patients will respond favorably to NACT, with the potential to help reduce overtreatment.

Risk stratification of ER-positive breast cancer patients: A multi-institutional validation and outcome study of the Rochester Modified Magee algorithm (RoMMa) and prediction of an Oncotype DX® recurrence score <26

The skyrocketing cost of health-care demands that we question when to use multigene assay testing in the planning of treatment for breast cancer patients. A previously published algorithmic model gave recommendations for which cases to send out for Oncotype DX^® (ODX) testing. This study is a multi-institutional validation of that algorithmic model in 620 additional estrogen receptor positive breast cancer cases, with outcome data on 310 cases, named in this study as the Rochester Modified Magee algorithm (RoMMa). RoMMa correctly predicted 85% (140/164) and 100% (17/17) of cases to have a low- or high-risk ODX recurrence score, respectively, consistent with the original publication. Applying our own risk stratification criteria, in patients who received appropriate hormonal therapy, only one of the 45 (2.0%) patients classified as low risk by our original algorithm have been associated with a breast cancer recurrence over 5-10 years of follow-up. Eight of 116 (7.0%) patients classified as low risk by ODX have been associated with a breast cancer recurrence with up to 11 years of follow-up. In addition, 524 of 537 (98%) cases from our total population (n = 903) with an average modified Magee score ≤18 had an ODX recurrence score <26. Patients with an average modified Magee score ≤18 or >30 may not need to be sent out for ODX testing. By avoiding these cases sending out for ODX testing, the potential cost savings to the health-care system in 2018 are estimated to have been over $100,000,000.

Abstract P2-08-40: Reconsidering “at risk” criteria for breast cancer recurrence in hormone positive patients: Risk stratification is still important in patients with an Oncotype Dx recurrence score ≤ 25!

Introduction: The recent TAILORx results suggest that additional systemic chemotherapy may not be necessary in certain hormone +, HER2 -, node negative breast cancer patients with an Oncotype Dx recurrence score (ODXRS) ≤ 25. ODX is an expensive test (current list price of $4,650.00), and cost has been an impediment to its adoption in many centers throughout the world. Based on a modification of the new Magee equations (Klein ME, et al. Mod Pathol. 26[5]) we published data based on 283 patients with ODXRS's (Turner BM, et al. Mod Pathol. 28[7]), suggesting that the modified Magee equation (MME) offered a less expensive alternative to ODX testing in certain breast cancer patients. We now have outcome data suggesting that the MME along with progesterone receptor (PR), Ki-67, lymph node (LN) status, and lymphovascular invasion (LVI) status can be helpful in predicting which patients with an ODXRS ≤ 25 are more likely to recur. Methods: 248 patients with information on estrogen receptor (ER), PR, Ki-67, Her-2 status, Nottingham score, tumor size, LN status, LVI status, and an available ODXRS (2008-2018) were identified from the pathology files at the University of Rochester Medical Center. Results: All of the patients that recurred had an average modified Magee score (MMS) ≥ 14 (Table 1). Patients with LN involvement (5/43,12% ) or with LVI (5/27,19%) had a higher percentage of recurrence than patients without LN involvement (8/197, 4%) or without LVI (8/216, 4%). Patients that recurred had a significantly (p &lt; 0.05) lower PR and higher Ki-67 than patients in the same risk class that did not recur (Table 2). Neither grade nor ER status was significantly different between patients that recurred and did not recur (Table 2). All of the patients that recurred had at least a lowered PR, higher Ki-67, LN involvement, or LVI, and most had some combination of these variables (Table 1). 8 of the 13 patients that recurred in our population (61.5%) had an ODXRS of ≤ 25. Conclusions: Risk stratification is still important in patients with an ODX score ≤ 25. The MMS along with PR, Ki-67, LN, and LVI status can be helpful in predicting patients with a higher risk of recurrence.

Table 1:Recurrence dataODXRSMMSType of therapy*Nodal and LVI status**Nottingham scoreER-H score***PR-H score***Ki-671119.1NONENONE6240180271319.7HNONE530015201521.6HN51209051514HNONE5270210UNKNOWN1615HLVI527018051727.2HB62701601916.3HNONE428545UNKNOWN2424.5CLVI8240105352723.9BNONE7210100352821HN527021252823.4HB528530353128.7HB82701454432.3HNONE9210607021.4****21.4****--5.9****250.7****93.4****31.4*****H = Hormone only;C = Chemo only;B = Both; ** N = Nodal involvement;L = LVI;B = Both; ***modified (Turner BM, et al. Mod Pathol. 2015;28(7):921-31); **** average

Table 2:Recurrence data in specific populationsPopulation typeNGradeER*PR*Ki-67≤ 25 no recurrence2165.4249.7185.712.8**≤ 25 recurrence85.5249.4103.325.3***&gt; 25 no recurrence267.3211.776.834.1****&gt; 25 recurrence56.8249.042.542.0* modified (Turner BM, et al. Mod Pathol. 2015;28(7):921-31); ** n = 181; *** n = 6; **** n = 23

Citation Format: Turner BM, Sanders MAG, Soukiazian A, Soukiazian N, Hicks DG. Reconsidering “at risk” criteria for breast cancer recurrence in hormone positive patients: Risk stratification is still important in patients with an Oncotype Dx recurrence score ≤ 25! [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-40.

Abstract P6-09-05: Optical Prediction of Time Interval to Metastasis (OPTIM): A rapid nondestructive optical assay applied to tissue microarray samples identifying high risk of distant recurrence in the lowest risk groups defined by the TAILORx trial

Recent reporting of the 9 year follow-up for the TAILORx trial suggests that there may be no benefit with adjuvant chemotherapy for ER +, HER2 -, N(0) breast cancer patients with a Oncotype DX® (ODX) recurrence score (RS) &lt;26. Since endocrine therapy for this group of patients who comply with treatment still results in distant recurrence (rMBC) in 3% and 5% of the ODX low and ODX intermediate risk groups at 9 years, respectively, we are motivated to help find early treatments for these patients by identifying their recurrence risk at diagnosis with improved risk stratification.

Methods: Optical Prediction of Time Interval to Metastasis (OPTIM), a novel assay, prognostic for rMBC, is based on an intrinsic optical signature from collagen, derived from the average of point by point ratios of forward to backward (F/B) second harmonic generation (SHG) light scatter that is sensitive to form and structure of fibrillar collagen in the extracellular matrix of archival tissue microarray samples. (Burke et al. BMC Cancer 15 (2015): 929). The 125 patients in this cohort were part of a clinical trial, looking for genomic predictors of rMBC in untreated patients, so we were able to calculate a surrogate 21-gene RT-PCR assay (S-ODX) value based on gene expression data available through NCBI GEO database (Gyorffy et al. Breast Cancer Res Treat (2012) 132:1025). We analyzed these patient's rMBC outcomes using logistic regression and Kaplan-Meier (KM) analysis.

Results: OPTIM alone stratified at 2.5X relative risk (RR) between quartiles Q1 and Q4, similar to S-ODX low vs high recurrence score (RS) groups (from TAILORx Trial) with 2.8X RR. Using quartiles of OPTIM vs S-ODX together we stratify patients to recurrence risk (rMBC/at Risk), with an improved risk stratification of 5X RR in the RS&lt;26 low risk groups.

OPTIM Quartiles vs RS Risk Groups in TAILORx TrialS-ODX →High (RS&gt;25)Intermediate (RS 11-25)Low (RS &lt;11)AllOPTIM↓↓↓↓Q17/97/12*5/1019/31*Q25/95/142/812/31Q38/12***1/81/11***10/31Q46/10**2/17*0/5**8/32*All26/40***15/518/34***49/125Recurrence at 10 years by KM analysis *p&lt;0.05, **p&lt;0.005, ***p&lt;.0005

Combining S-ODX with OPTIM, low (L) or high (H) risk by assay, shows that they are independent and complementary. Notably 68%=85/125 are classified L by S-ODX (RS&lt;26) and OPTIM effectively reclassifies H and L, and when combined with S-ODX H identifies 92%=45/49 of all rMBC at 10 years without treatment. Risk stratification improves to 6.8X RR comparing highest risk HH 66.7%=12/18 to lowest risk LL 9.8%=4/41.

Distant Recurrence Identified by High Risk Group of Each AssayS-ODX AssayHHLLOPTIM AssayHLHLrMBC (total=49)1214194At Risk (total n=125)18224441rMBC at 10 yrs. S-ODX RS&gt;25=H, RS&lt;26=L; OPTIM Q1&Q2=H, Q3&Q4=L

Conclusion: OPTIM as an independent prognostic optical bio-marker from collagen in intact tissue. Combination of OPTIM with the Oncotype DX® assay may produce a continuous risk estimator with higher dynamic range than either assay alone and will be the focus of future study, especially in a treated population, to determine if OPTIM might also predict response to treatment.

Citation Format: Hill RL, Perry SW, Salzman P, Turner BM, Hicks DG, Brown EB. Optical Prediction of Time Interval to Metastasis (OPTIM): A rapid nondestructive optical assay applied to tissue microarray samples identifying high risk of distant recurrence in the lowest risk groups defined by the TAILORx trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-05.

Pathologic diagnosis of breast cancer patients: evolution of the traditional clinical-pathologic paradigm toward "precision" cancer therapy

We present an updated account of breast cancer treatment and of progress toward "precision" cancer therapy; we focus on new developments in diagnostic molecular pathology and breast cancer that have emerged during the past 2 years. Increasing awareness of new prognostic and predictive methodologies, and introduction of next generation sequencing has increased understanding of both tumor biology and clinical behavior, which offers the possibility of more appropriate therapeutic choices. It remains unclear which of these testing methodologies provides the most informative and cost-effective actionable results for predictive and prognostic pathology. It is likely, however, that an integrated "step-wise" approach that uses the traditional clinical-pathologic paradigms coordinated with molecular characterization of breast tumor tissue, will offer the most comprehensive and cost-effective options for individualized, "precision" therapy for patients with breast cancer.

Optimizing the Use of Gene Expression Profiling in Early-Stage Breast Cancer

Purpose Gene expression profiling assays are frequently used to guide adjuvant chemotherapy decisions in hormone receptor-positive, lymph node-negative breast cancer. We hypothesized that the clinical value of these new tools would be more fully realized when appropriately integrated with high-quality clinicopathologic data. Hence, we developed a model that uses routine pathologic parameters to estimate Oncotype DX recurrence score (ODX RS) and independently tested its ability to predict ODX RS in clinical samples. Patients and Methods We retrospectively reviewed ordered ODX RS and pathology reports from five institutions (n = 1,113) between 2006 and 2013. We used locally performed histopathologic markers (estrogen receptor, progesterone receptor, Ki-67, human epidermal growth factor receptor 2, and Elston grade) to develop models that predict RS-based risk categories. Ordering patterns at one site were evaluated under an integrated decision-making model incorporating clinical treatment guidelines, immunohistochemistry markers, and ODX. Final locked models were independently tested (n = 472). Results Distribution of RS was similar across sites and to reported clinical practice experience and stable over time. Histopathologic markers alone determined risk category with > 95% confidence in > 55% (616 of 1,113) of cases. Application of the integrated decision model to one site indicated that the frequency of testing would not have changed overall, although ordering patterns would have changed substantially with less testing of estimated clinical risk-high or clinical risk-low cases and more testing of clinical risk-intermediate cases. In the validation set, the model correctly predicted risk category in 52.5% (248 of 472). Conclusion The proposed model accurately predicts high- and low-risk RS categories (> 25 or ≤ 25) in a majority of cases. Integrating histopathologic and molecular information into the decision-making process allows refocusing the use of new molecular tools to cases with uncertain risk.

Use of modified Magee equations and histologic criteria to predict the Oncotype DX recurrence score

Oncotype DX (Genomic Health, Redwood City, CA, USA, current list price $4,350.00) is a multigene quantitative reverse transcription-polymerase chain reaction-based assay that estimates the risk of distant recurrence and predicts chemotherapy benefit for patients with estrogen receptor (ER)-positive breast cancers. Studies have suggested that standard histologic variables can provide similar information. Klein and Dabbs et al have shown that Oncotype DX recurrence scores can be estimated by incorporating standard histologic variables into equations (Magee equations). Using a simple modification of the Magee equation, we predict the Oncotype DX recurrence score in an independent set of 283 cases. The Pearson correlation coefficient (r) for the Oncotype DX and average modified Magee recurrence scores was 0.6644 (n=283; P<0.0001). 100% of cases with an average modified Magee recurrence score>30 (n=8) or an average modified Magee recurrence score<9 (with an available Ki-67, n=5) would have been correctly predicted to have a high or low Oncotype DX recurrence score, respectively. 86% (38/44) of cases with an average modified Magee recurrence score≤12, and 89% (34/38) of low grade tumors (NS<6) with an ER and PR≥150, and a Ki-67<10%, would have been correctly predicted to have a low Oncotype DX recurrence score. Using an algorithmic approach to eliminate high and low risk cases, between 5% and 23% of cases would potentially not have been sent by our institution for Oncotype DX testing, creating a potential cost savings between $56,550.00 and $282,750.00. The modified Magee recurrence score along with histologic criteria may be a cost-effective alternative to the Oncotype DX in risk stratifying certain breast cancer patients. The information needed is already generated by many pathology laboratories during the initial assessment of primary breast cancer, and the equations are free.

Abstract P1-08-37: Magee equations predict pathologic response to neoadjuvant chemotherapy

Introduction: Neoadjuvant chemotherapy is used in locally advanced breast cancer to downstage the tumor, facilitating surgical management. Oncotype DX (ODX) is used to estimate the risk of distant recurrence for ER-positive breast cancers, allowing selected patients to avoid the toxicity of chemotherapy. ODX is often not possible on the small core biopsy samples. Klein et al. have shown that standard histological variables, combined with semiquantitative ER, PR, HER-2, and Ki-67 results, can provide information similar to that with ODX, using equations derived by linear regression analysis (Magee equations). We applied a modification of these equations to pretreatment core biopsies in women who received neoadjuvant chemotherapy to determine if the risk scores were predictive of pathologic response.

Methods: 25 patients who received chemotherapy for receptor positive locally advanced(21), inflammatory(3), or metastatic(1) breast cancer followed by surgical treatment of the primary site were identified from a prospective breast cancer database. Pretreatment core biopsies were reviewed by a breast pathologist and Nottingham grade, ER and PR status (% of cells staining and intensity of staining), and Her-2 status by IHC and/or FISH were recorded. Clinical tumor size was defined as the average of sizes derived from mammogram, ultrasound, MRI, PET-CT and clinical breast examination. Using these data in a modified Magee equation, the patient's recurrence score was calculated. 0-18 was considered low risk (LR), &gt;18-&lt;30 was considered intermediate risk (IR), and ≥30 was considered high risk (HR). Resection specimens were reviewed to define pathologic response. A good pathologic response to chemotherapy was defined as a complete pathologic response (3 cases), near complete response (2), or a response with one or more of the following; reduction in the post-treatment size of the tumor by greater than 50% compared with pretreatment imaging, a significant reduction in tumor cellularity in the tumor bed, and an inflammatory lymphohistiocytic infiltrate with tumor necrosis (6 cases). For the remaining 14 cases, the response was defined as poor (no histopathologic evidence of response to treatment). Risk scores were compared between good and poor responders using T-Test. Comparison between risk groups (HR vs IR vs LR) were made using Chi Square analysis.

Results: Magee scores ranged from 13.8-41.6 (mean 27.4) and were significantly lower in the poor responders (mean = 23, range 13.8-41.6) compared to the good responders (mean = 33, range 22-41.3, p = 0.003). Table 1 shows the distribution of response by Risk Group (p = 0.018).

Table 1: Response by Risk CategoryMagee Risk GroupLRIRHRPoor Response563Good Response038

73% of patients with high risk Magee scores had a good response to chemotherapy, compared to 21% of patient with low or intermediate scores (p = 0.01).

Conclusions: Modified Magee equations applied to pretreatment core biopsies seem to predict pathologic response to neoadjuvant chemotherapy. Use of these equations to assign risk scores may be a useful tool in deciding which ER positive breast cancer patients are likely to benefit from preoperative chemotherapy for cytoreduction, and who should go directly to surgery. These findings need to be validated in larger studies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-37.

Napsin A, a new marker for lung adenocarcinoma, is complementary and more sensitive and specific than thyroid transcription factor 1 in the differential diagnosis of primary pulmonary carcinoma: evaluation of 1674 cases by tissue microarray

CONTEXT

Differentiation of non-small cell carcinoma into histologic types is important because of new, successful therapies that target lung adenocarcinoma (ACA). TTF-1 is a favored marker for lung ACA but has limited sensitivity and specificity. Napsin A (Nap-A) is a functional aspartic proteinase that may be an alternative marker for primary lung ACA.

OBJECTIVES

To compare Nap-A versus TTF-1 in the typing of primary lung carcinoma and the differentiation of primary lung ACA from carcinomas of other sites.

DESIGN

Immunohistochemistry for Nap-A and TTF-1 was performed on tissue microarrays of 1674 cases of carcinoma: 303 primary lung ACAs (18.1%), 200 primary squamous cell lung carcinomas (11.9%), 52 primary small cell carcinomas of the lung (3.1%), and carcinomas of the kidney (n  =  320; 19.1%), thyroid (n  =  96; 5.7%), biliary (n  =  89; 5.3%), bladder (n  =  47; 2.8%), breast (n  =  93; 5.6%), colon (n  =  95; 5.7%), liver (n  =  96; 5.7%), ovaries (n  =  45; 2.7%), pancreas (n  =  48; 2.9%), prostate (n  =  49; 2.9%), stomach (n  =  93; 5.6%), and uterus (n  =  48; 2.9%). Cases were evaluated against a negative control as negative, weak positive, and strong positive.

RESULTS

Nap-A was more sensitive than TTF-1 for primary lung ACA (87% versus 64%; P < .001). Nap-A was more specific than TTF-1 for primary lung ACA versus all tumors, excluding kidney, independent of tumor type (P < .001).

CONCLUSIONS

Nap-A is superior to TTF-1 in distinguishing primary lung ACA from other carcinomas (except kidney), particularly primary lung small cell carcinoma, and primary thyroid carcinoma. A combination of Nap-A and TTF-1 is useful in the distinction of primary lung ACA (Nap-A(+), TTF-1(+)) from primary lung squamous cell carcinoma (Nap-A(-), TTF-1(-)) and primary lung small cell carcinoma (Nap-A(-), TTF-1(+)).

Abstract P2-06-15: The Use of ADH-5 Stain as a Surrogate Marker for Molecular Classification of Basal and Luminal Breast Cancers

BACKGROUND: Immunohistochemical (IHC) analyses of protein expression have recently been used as surrogate assays for the molecular classification of breast cancers. Specifically, ER+/PR+/HER2- tumors are typically considered luminal-type breast cancers, ER-/PR-/HER2+ tumors equate to HER2 over-expressing tumors, whereas ER-/PR-/HER2- (triple negative, TN) tumors are basal-like breast cancers. A newly available cocktail of antibodies called ADH-5 allows for the simultaneous evaluation of both luminal and basal keratins. In this study, we examine the expression of luminal and basal keratins in breast cancers stained with ADH-5, particularly in a subgroup of basal keratin positive tumors. METHODS: All invasive breast cancers from 12/2009-6/2010 in a single pathology laboratory were studied by ADH-5 antibody cocktail consisting of two luminal keratin (LK) markers (CK7 and CK18), and two basal keratin (BK) markers (CK5 and CK14), as well as a myoepithelial marker, P63 (Biocare, Concord, CA). ER, PR, HER2 and Ki-67 were also evaluated by IHC and scored in all tumors. The group included 81 breast cancers and 3 metastatic tumors from the breast. ADH-5 staining was evaluated in areas of invasive carcinoma, and intensity and proportion of staining by BK and LK were scored. Mean statistics and ratios were evaluated and compared for each of the scored stains using the student t-test (stt) and chi squared analysis (cs), respectively.

RESULTS: Of the 84 cancers, 20 (24%) showed some staining for BK, and 63 (75%) showed only LK staining. One case (1%) showed no staining for either BK or LK. Of the BK+ cases, 19/20 (95%) showed some degree of LK staining as well. Only one BK+ tumor lacked luminal keratin positivity (5%). Co-expression both BK and LK was seen in the same cells, though many cells were more strongly positive for one keratin type. The BK+ tumors were significantly more likely to be TN (p = 0.5, cs), and all TN tumors showed some BK staining. Four ER+/PR+/HER2- tumors expressed low levels of BK; two additional ER+/PR+/HER2+ tumors also expressed BK. ER-, PR-and TN tumors tended to show a significantly greater proportion of BK staining and decreased amount of luminal staining than ER+, PR+ and non-TN tumors.

DISCUSSION: ADH-5 stain demonstrates co-expression of luminal keratins in basal keratin positive breast cancers, including all triple negative breast cancers in our study. In addition, some ER+/PR+/HER2- tumors and ER+/PR+/HER2+ (considered luminal A and B, respectively, by current usage of ER/PR/HER2 as surrogate markers) actually express basal keratins, bringing up the issue of whether these tumors should be considered luminal or basal-like. The ADH-5 stain may be helpful as a surrogate molecular marker for the classification of breast cancers.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-15.

The AmpC inhibitor, Syn2190, can be used to reveal extended-spectrum beta-lactamases in Escherichia coli

AmpC beta-lactamases are not inhibited by clavulanic acid and could potentially mask detection of extended-spectrum beta-lactamases (ESBLs) using the Clinical and Laboratory Standards Institute confirmatory test. Syn2190 (1,5-dihydroxy-4-pyridone monobactam) selectively inhibits AmpC, but not ESBLs. Fifty-four MicroScan ESBL screen-positive strains of Escherichia coli and an unrelated group of 20 cefoxitin-nonsusceptible E. coli strains were tested with the confirmatory ceftazidime-cefotaxime-clavulanate disk method with or without 4 microg/mL of Syn2190 in the agar. Without Syn2190, 8 (14.8%) of 54 E. coli isolates and 0 of 20 cefoxitin-nonsusceptible E. coli isolates were confirmed. With Syn2190, an additional 9 (16.6%) of 54 of the MicroScan screen-positive E. coli isolates and 6 (30%) of 20 of the cefoxitin-nonsusceptible E. coli isolates were found. Multiplex polymerase chain reaction and sequence analysis confirmed the presence of the plasmid-associated beta-lactamase gene bla(CMY-2) in the 2 available MicroScan-screened E. coli isolates and in 5 of 6 of the cefoxitin-resistant group. These data suggest that in the presence of AmpC, ESBLs in E. coli may not be detected by the currently recommended confirmatory test.

Histone deacetylases in acute myeloid leukaemia show a distinctive pattern of expression that changes selectively in response to deacetylase inhibitors

Histone deacetylase inhibitors (HDIs) are a new class of drugs with significant antileukemic activity. To explore mechanisms of disease-specific HDI activity in acute myeloid leukaemia (AML), we have characterised expression of all 18 members of the histone deacetylase family in primary AML blasts and in four control cell types, namely CD34+ progenitors from umbilical cord, either quiescent or cycling (post-culture), cycling CD34+ progenitors from GCSF-stimulated adult donors and peripheral blood mononuclear cells. Only SIRT1 was consistently overexpressed (>2 fold) in AML samples compared with all controls, while HDAC6 was overexpressed relative to adult, but not neo-natal cells. HDAC5 and SIRT4 were consistently underexpressed. AML blasts and cell lines, exposed to HDIs in culture, showed both histone hyperacetylation and, unexpectedly, specific hypermethylation of H3 lysine 4. Such treatment also modulated the pattern of HDAC expression, with strong induction of HDAC11 in all myeloid cells tested and with all inhibitors (valproate, butyrate, TSA, SAHA), and lesser, more selective, induction of HDAC9 and SIRT4. The distinct pattern of HDAC expression in AML and its response to HDIs is of relevance to the development of HDI-based therapeutic strategies and may contribute to observed patterns of clinical response and development of drug resistance.

Identification of a conserved erythroid specific domain of histone acetylation across the alpha-globin gene cluster

We have analyzed the pattern of core histone acetylation across 250 kb of the telomeric region of the short arm of human chromosome 16. This gene-dense region, which includes the alpha-globin genes and their regulatory elements embedded within widely expressed genes, shows marked differences in histone acetylation between erythroid and non-erythroid cells. In non-erythroid cells, there was a uniform 2- to 3-fold enrichment of acetylated histones, compared with heterochromatin, across the entire region. In erythroid cells, an approximately 100-kb segment of chromatin encompassing the alpha genes and their remote major regulatory element was highly enriched in histone H4 acetylated at Lys-5. Other lysines in the N-terminal tail of histone H4 showed intermediate and variable levels of enrichment. Similar broad segments of erythroid-specific histone acetylation were found in the corresponding syntenic regions containing the mouse and chicken alpha-globin gene clusters. The borders of these regions of acetylation are located in similar positions in all three species, and a sharply defined 3' boundary coincides with the previously identified breakpoint in conserved synteny between these species. We have therefore demonstrated that an erythroid-specific domain of acetylation has been conserved across several species, encompassing not only the alpha-globin genes but also a neighboring widely expressed gene. These results contrast with those at other clusters and demonstrate that not all genes are organized into discrete regulatory domains.

General transcription factors bind promoters repressed by Polycomb group proteins

To maintain cell identity during development and differentiation, mechanisms of cellular memory have evolved that preserve transcription patterns in an epigenetic manner. The proteins of the Polycomb group (PcG) are part of such a mechanism, maintaining gene silencing. They act as repressive multiprotein complexes that may render target genes inaccessible to the transcriptional machinery, inhibit chromatin remodelling, influence chromosome domain topology and recruit histone deacetylases (HDACs). PcG proteins have also been found to bind to core promoter regions, but the mechanism by which they regulate transcription remains unknown. To address this, we used formaldehyde-crosslinked chromatin immunoprecipitation (X-ChIP) to map TATA-binding protein (TBP), transcription initiation factor IIB (TFIIB) and IIF (TFIIF), and dHDAC1 (RPD3) across several Drosophila promoter regions. Here we show that binding of PcG proteins to repressed promoters does not exclude general transcription factors (GTFs) and that depletion of PcG proteins by double-stranded RNA interference leads to de-repression of developmentally regulated genes. We further show that PcG proteins interact in vitro with GTFs. We suggest that PcG complexes maintain silencing by inhibiting GTF-mediated activation of transcription.

DNA methylation is linked to deacetylation of histone H3, but not H4, on the imprinted genes Snrpn and U2af1-rs1

The relationship between DNA methylation and histone acetylation at the imprinted mouse genes U2af1-rs1 and Snrpn is explored by chromatin immunoprecipitation (ChIP) and resolution of parental alleles using single-strand conformational polymorphisms. The U2af1-rs1 gene lies within a differentially methylated region (DMR), while Snrpn has a 5' DMR (DMR1) with sequences homologous to the imprinting control center of the Prader-Willi/Angelman region. For both DMR1 of Snrpn and the 5' untranslated region (5'-UTR) and 3'-UTR of U2af1-rs1, the methylated and nonexpressed maternal allele was underacetylated, relative to the paternal allele, at all H3 lysines tested (K14, K9, and K18). For H4, underacetylation of the maternal allele was exclusively (U2af1-rs1) or predominantly (Snrpn) at lysine 5. Essentially the same patterns of differential acetylation were found in embryonic stem (ES) cells, embryo fibroblasts, and adult liver from F1 mice and in ES cells from mice that were dipaternal or dimaternal for U2af1-rs1. In contrast, in a region within Snrpn that has biallelic methylation in the cells and tissues analyzed, the paternal (expressed) allele showed relatively increased acetylation of H4 but not of H3. The methyl-CpG-binding-domain (MBD) protein MeCP2 was found, by ChIP, to be associated exclusively with the maternal U2af1-rs1 allele. To ask whether DNA methylation is associated with histone deacetylation, we produced mice with transgene-induced methylation at the paternal allele of U2af1-rs1. In these mice, H3 was underacetylated across both the parental U2af1-rs1 alleles whereas H4 acetylation was unaltered. Collectively, these data are consistent with the hypothesis that CpG methylation leads to deacetylation of histone H3, but not H4, through a process that involves selective binding of MBD proteins.

Chromatin remodeling at the Ig loci prior to V(D)J recombination

Rearrangement of Ig H and L chain genes is highly regulated and takes place sequentially during B cell development. Several lines of evidence indicate that chromatin may modulate accessibility of the Ig loci for V(D)J recombination. In this study, we show that remodeling of V and J segment chromatin occurs before V(D)J recombination at the endogenous H and kappa L chain loci. In recombination-activating gene-deficient pro-B cells, there is a reorganization of nucleosomal structure over the H chain J(H) cluster and increased DNase I sensitivity of V(H) and J(H) segments. The pro-B/pre-B cell transition is marked by a decrease in the DNase I sensitivity of V(H) segments and a reciprocal increase in the nuclease sensitivity of Vkappa and Jkappa segments. In contrast, J(H) segments remain DNase I sensitive, and their nucleosomal organization is maintained in mu(+) recombination-activating gene-deficient pre-B cells. These results indicate that initiation of rearrangement is associated with changes in the chromatin structure of both V and J segments, whereas stopping recombination involves changes in only V segment chromatin. We further find an increase in histone H4 acetylation at both the H and kappa L chain loci at the pro-B cell stage. Although histone H4 acetylation appears to be an early change associated with B cell commitment, acetylation alone is not sufficient to promote subsequent modifications in Ig chromatin.