eEF1A2 promotes PTEN-GSK3β-SCF complex-dependent degradation of Aurora kinase A and is inactivated in breast cancer

The translation elongation factor eEF1A promotes protein synthesis. Its methylation by METTL13 increases its activity, supporting tumor growth. However, in some cancers, a high abundance of eEF1A isoforms is associated with a good prognosis. Here, we found that eEF1A2 exhibited oncogenic or tumor-suppressor functions depending on its interaction with METTL13 or the phosphatase PTEN, respectively. METTL13 and PTEN competed for interaction with eEF1A2 in the same structural domain. PTEN-bound eEF1A2 promoted the ubiquitination and degradation of the mitosis-promoting Aurora kinase A in the S and G2 phases of the cell cycle. eEF1A2 bridged the interactions between the SKP1-CUL1-FBXW7 (SCF) ubiquitin ligase complex, the kinase GSK3β, and Aurora-A, thereby facilitating the phosphorylation of Aurora-A in a degron site that was recognized by FBXW7. Genetic ablation of Eef1a2 or Pten in mice resulted in a greater abundance of Aurora-A and increased cell cycling in mammary tumors, which was corroborated in breast cancer tissues from patients. Reactivating this pathway using fimepinostat, which relieves inhibitory signaling directed at PTEN and increases FBXW7 expression, combined with inhibiting Aurora-A with alisertib, suppressed breast cancer cell proliferation in culture and tumor growth in vivo. The findings demonstrate a therapeutically exploitable, tumor-suppressive role for eEF1A2 in breast cancer.

A Comparative Evaluation of TRPS1 and GATA3 in adenoid cystic, secretory, and acinic cell carcinomas of the breast and salivary gland

GATA3 is the most used marker to determine tumors' breast origin, but its diagnostic value in triple-negative breast cancer (TNBC) is limited. The newly identified TRPS1 is highly sensitive and specific for breast carcinoma, especially TNBC. Here, we compared the utility of TRPS1 and GATA3 expression in a subset of salivary gland-type breast tumors (including adenoid cystic, acinic cell, and secretory carcinomas [AdCC, ACC, and SC, respectively]), and we compared TRPS1 and GATA3 expression of such tumors with head and neck (H&N) and AdCC of upper respiratory tumors. TRPS1 was strongly expressed in basaloid TNBC and AdCCs with solid components, including 100 % of mixed and solid breast AdCCs. However, TRPS1 was positive in only 50 % cribriform AdCCs. Expression patterns of TRPS1 in H&N and upper respiratory AdCC were similar. TRPS1 was positive in 30 % of H&N cribriform AdCCs but was strongly expressed in mixed AdCC (67 %) and solid AdCC (100 %). In the upper respiratory AdCCs, TRPS1 was positive in 58.4 % of cribriform AdCCs and positive in 100 % of AdCCs with solid components. On the contrary, GATA3 was negative in predominant AdCCs of the breast, H&N, and upper respiratory tract. These data show that GATA3 and TRPS1 expression varies AdCCs. In addition, TRPS1 and GATA3 expression patterns were similar SC and ACC of breast and H&N. Both markers were positive in SC and negative in ACC. Therefore, TRPS1 and GATA3 cannot be used to differentiate salivary gland-type carcinomas of breast origin from those of upper respiratory or H&N origin.

Comparison of PD-L1 (22C3) Expression in Paired Primary and Metastatic Breast Carcinoma

INTRODUCTION

PD-L1 immunohistochemistry (IHC) is being used as a predictive marker of the benefit derived from immunotherapy in several cancer types, including breast cancer. However, the insight gleaned of the prognostic and predictive value of PD-L1 status and its correlation with molecular characteristics during breast cancer progression remains limited.

METHODS

We performed an PD-L1 (22C3) assay in pre-treatment primary and metastatic tumor sections from 33 patients with breast carcinoma, matched for post neoadjuvant chemotherapy (p-NACT). PD-L1 expression was evaluated using 3 scoring methods: immune cell (IC) and tumor cell (TC) with a 1% as the cutoff value, and combined positive scores (CPS) with a 1 as the cutoff value. Twenty-two samples from 11 patients had successful fluorescence in situ hybridization (FISH)-based molecular data available for analysis.

RESULTS

In the 33 pre-treatment primary tumors, PD-L1 IC, TC, and CPS showed positive correlation with stromal tumor infiltrate lymphocytes (sTIL), histological grade 3, and triple negative breast carcinoma (TNBC). In the matched metastatic tumors, only PD-L1 IC showed a positive correlation with sTIL. The primary tumors showed a higher PD-L1 expression than the matched metastatic tumors by IC and CPS. Negative to positive conversion by CPS was identified in the metastatic tumors from lung, pleura and liver. p-NACT tumors also showed a trend of lower PD-L1 expression compared to the pre-treatment tumors. Six patients had matched samples for molecular and PD-L1 comparison, and none of them showed consistent gene alterations or PD-L1 expression among the primary, p-NACT and metastatic tumors.

CONCLUSION

Our study showed a decrease in PD-L1 expression and disconnected molecular features during breast cancer progression. Repeating PD-L1 IHC testing could be considered in some specific metastatic sites if primary tumors were negative. Further studies are needed to identify other predictive factors for immune checkpoint inhibitor (ICI) therapy in patients with breast carcinoma.

TRPS1 and GATA3 Expression in Invasive Breast Carcinoma With Apocrine Differentiation

CONTEXT.—

The recently identified immunohistochemical marker TRPS1 is highly sensitive and specific for invasive breast carcinoma, especially triple-negative breast carcinoma. However, TRPS1 expression in special morphologic subtypes of breast cancer is unclear.

OBJECTIVE.—

To investigate the expression of TRPS1 in invasive breast cancer with apocrine differentiation, in comparison to the expression of GATA3.

DESIGN.—

A total of 52 invasive breast carcinomas with apocrine differentiation, comprising 41 triple-negative breast carcinomas and 11 estrogen receptor (ER) and progesterone receptor (PR)-negative, human epidermal growth factor receptor 2 (HER2)-positive cases, along with 11 triple-negative breast carcinomas without apocrine differentiation, were evaluated for TRPS1 and GATA3 expression by immunohistochemistry. All tumors were diffusely positive (>90%) for androgen receptor (AR).

RESULTS.—

Triple-negative breast carcinoma with apocrine differentiation had positive TRPS1 expression in 12% of cases (5 of 41), whereas GATA3 was positive in all cases. Similarly, HER2+/ER- invasive breast carcinoma with apocrine differentiation showed positive TRPS1 in 18% of cases (2 of 11), whereas GATA3 was positive in all cases. In contrast, triple-negative breast carcinoma with strong AR expression but without apocrine differentiation showed both TRPS1 and GATA3 expression in 100% (11 of 11) of cases.

CONCLUSIONS.—

Most ER-/PR-/AR+ invasive breast carcinomas with apocrine differentiation are TRPS1 negative and GATA3 positive, regardless of HER2 status. Therefore, TRPS1 negativity does not exclude breast origin in tumors with apocrine differentiation. A panel of TRPS1 and GATA3 immunostains can be helpful when the tissue origin of such tumors is clinically relevant.

Identification of Glandular (Acinar)/Tubule Formation in Invasive Carcinoma of the Breast: A Study to Determine Concordance Using the World Health Organization Definition

CONTEXT.—

The Nottingham Grading System (NGS) developed by Elston and Ellis is used to grade invasive breast cancer (IBC). Glandular (acinar)/tubule formation is a component of NGS.

OBJECTIVE.—

To investigate the ability of pathologists to identify individual structures that should be classified as glandular (acinar)/tubule formation.

DESIGN.—

A total of 58 hematoxylin-eosin photographic images of IBC with 1 structure circled were classified as tubules (41 cases) or nontubules (17 cases) by Professor Ellis. Images were sent as a PowerPoint (Microsoft) file to breast pathologists, who were provided with the World Health Organization definition of a tubule and asked to determine if a circled structure represented a tubule.

RESULTS.—

Among 35 pathologists, the κ statistic for assessing agreement in evaluating the 58 images was 0.324 (95% CI, 0.314-0.335). The median concordance rate between a participating pathologist and Professor Ellis was 94.1% for evaluating 17 nontubule cases and 53.7% for 41 tubule cases. A total of 41% of the tubule cases were classified correctly by less than 50% of pathologists. Structures classified as tubules by Professor Ellis but often not recognized as tubules by pathologists included glands with complex architecture, mucinous carcinoma, and the "inverted tubule" pattern of micropapillary carcinoma. A total of 80% of participants reported that they did not have clarity on what represented a tubule.

CONCLUSIONS.—

We identified structures that should be included as tubules but that were not readily identified by pathologists. Greater concordance for identification of tubules might be obtained by providing more detailed images and descriptions of the types of structures included as tubules.

Intragenic EGFR::EGFR.E1E8 Fusion (EGFRvIII) in 4331 Solid Tumors

Epidermal growth factor receptor variant III (EGFRvIII, the deletion of exons 2-7) is a recurrent intragenic EGFR::EGFR.E1E8 fusion that occurs in high-grade gliomas. The presence of EGFRvIII in other solid tumors has not been well characterized. We retrospectively reviewed advanced malignant solid tumor cases tested by a custom hybrid capture 610-gene next-generation sequencing platform from 2021 to 2022. EGFRvIII was identified in 17 of 4331 (0.4%) cases, including 16 of 238 (7%) brain tumors and 1/301 (0.3%) breast tumors. EGFRvIII-positive brain tumors were all glioblastoma IDH-wildtype, most with concurrent TERT promoter mutation (14 of 16), EGFR amplification (13 of 16), and EGFR mutation (8 of 16). The only EGFRvIII-positive breast lesion was a sarcomatoid neoplasm in a young female patient. A separate breast case tested outside our institution with reported EGFRvIII was noted in a young female patient with a malignant phyllodes tumor with stromal overgrowth. Microscopically, both EGFRvIII-positive breast tumors showed high-grade sarcomatoid morphology with brisk mitotic activity. In summary, EGFRvIII is rare, occurring primarily in glioblastoma and rarely in breast sarcomatoid neoplasm, with no instances identified in other tumor types in our series. This select group of patients may benefit from chemotherapy and/or targeted anti-EGFR therapy.

Lobular Carcinoma of the Breast: A Comprehensive Review with Translational Insights

The second most common breast carcinoma, invasive lobular carcinoma, accounts for approximately 15% of tumors of breast origin. Its incidence has increased in recent times due in part to hormone replacement therapy and improvement in diagnostic modalities. Although believed to arise from the same cell type as their ductal counterpart, invasive lobular carcinomas (ILCs) are a distinct entity with different regulating genetic pathways, characteristic histologies, and different biology. The features most unique to lobular carcinomas include loss of E-Cadherin leading to discohesion and formation of a characteristic single file pattern on histology. Because most of these tumors exhibit estrogen receptor positivity and Her2 neu negativity, endocrine therapy has predominated to treat these tumors. However novel treatments like CDK4/6 inhibitors have shown importance and antibody drug conjugates may be instrumental considering newer categories of Her 2 Low breast tumors. In this narrative review, we explore multiple pathological aspects and translational features of this unique entity. In addition, due to advancement in technologies like spatial transcriptomics and other hi-plex technologies, we have tried to enlist upon the characteristics of the tumor microenvironment and the latest associated findings to better understand the new prospective therapeutic options in the current era of personalized treatment.

Abemaciclib Is Effective in Palbociclib-Resistant Hormone Receptor-Positive Metastatic Breast Cancers

Cyclin-dependent kinases 4/6 inhibitor (CDK4/6i) plus endocrine therapy (ET) is standard of care for patients with hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC). However, resistance to CDK4/6is plus ET remains a clinical problem with limited therapeutic options following disease progression. Different CDK4/6is might have distinct mechanisms of resistance, and therefore using them sequentially or targeting their differentially altered pathways could delay disease progression. To understand pathways leading to resistance to the CDK4/6is palbociclib and abemaciclib, we generated multiple in vitro models of palbociclib-resistant (PR) and abemaciclib-resistant (AR) cell lines as well as in vivo patient-derived xenografts (PDX) and ex vivo PDX-derived organoids (PDxO) from patients who progressed on CDK4/6i. PR and AR breast cancer cells exhibited distinct transcriptomic and proteomic profiles that sensitized them to different classes of inhibitors; PR cells upregulated G2-M pathways and responded to abemaciclib, while AR cells upregulated mediators of the oxidative phosphorylation pathway (OXPHOS) and responded to OXPHOS inhibitors. PDX and organoid models derived from patients with PR breast cancer remained responsive to abemaciclib. Resistance to palbociclib while maintaining sensitivity to abemaciclib was associated with pathway-specific transcriptional activity but was not associated with any individual genetic alterations. Finally, data from a cohort of 52 patients indicated that patients with HR-positive/HER2-negative MBC who progressed on palbociclib-containing regimens can exhibit a meaningful overall clinical benefit from abemaciclib-based therapy when administered after palbociclib. These findings provide the rationale for clinical trials evaluating the benefit of abemaciclib treatment following progression on a prior CDK4/6i.

SIGNIFICANCE

Palbociclib-resistant breast cancers respond to abemaciclib and express pathway-specific signatures of sensitivity, providing a biomarker-driven therapeutic option for patients with metastatic breast cancer following disease progression on cyclin-dependent kinases 4/6 inhibitors.

Immunohistochemistry in the Diagnosis and Classification of Breast Tumors

CONTEXT.—

In the clinical practice of breast pathology, immunohistochemistry (IHC) of different markers is widely used for the diagnosis and classification of breast lesions.

OBJECTIVE.—

To provide an overview of currently used and recently identified IHC stains that have been implemented in the field of diagnostic breast pathology.

DATA SOURCES.—

Data were obtained from literature review and clinical experience of the authors as breast pathologists.

CONCLUSIONS.—

In the current review, we summarize the common uses of IHC stains for diagnosing different types of breast lesions, especially invasive and noninvasive breast lesions, and benign and malignant spindle cell lesions. In addition, the cutting-edge knowledge of diagnostic carcinoma markers will lead us to further understand the different types of breast carcinoma and differentiate breast carcinomas from other carcinomas of similar morphology. Knowing the strengths and limitations of these markers is essential to the clinical practice of breast pathology.

Nuclear staining for pan-Trk by immunohistochemistry is highly specific for secretory carcinoma of breast: pan-Trk in various subtypes of breast carcinoma

AIMS

Secretory carcinoma of breast (SCB) typically harbours ETV6-NTRK3 gene fusion. Pan-Trk immunohistochemistry analysis (IHC) has been shown to be sensitive for SCB diagnosis. However, weak focal pan-Trk nuclear staining was previously found in 10% of non-secretory breast carcinomas. To further examine pan-Trk IHC specificity, we evaluated pan-Trk staining in various breast carcinoma subtypes.

METHODS

The study cohort consisted of 346 invasive breast carcinomas (IBCs), including 8 SCBs and 48 triple-negative histological mimickers (36 metaplastic carcinomas, including 12 matrix-producing carcinomas; 5 adenoid cystic carcinomas; 5 apocrine carcinomas; 2 acinic cell carcinomas), 101 triple-negative IBCs of no special type, 101 estrogen receptor (ER)-positive/HER2-negative IBCs and 88 HER2-positive IBCs. Six salivary gland secretory carcinomas were also included. Pan-Trk IHC was performed on tumours using a rabbit monoclonal pan-Trk antibody. Any nuclear staining in the invasive carcinoma cells was considered positive.

RESULTS

All 14 secretory carcinomas from breast and salivary gland exhibited moderate to strong pan-Trk nuclear staining. In contrast, no pan-Trk nuclear staining was identified in any of the 338 non-secretory IBCs. Focal cytoplasmic pan-Trk staining was observed in nine non-secretory IBCs (2.7%), and was considered nonspecific and negative.

CONCLUSIONS

Our results indicate that pan-Trk nuclear staining is highly specific for SCB. In low-grade to intermediate-grade IBCs that share histological features with SCB, adding pan-Trk to a routing panel of estrogen receptor/progesterone receptor/HER2 is highly diagnostic. Our results also support using pan-Trk IHC to differentiate SCB from its triple-negative histological mimickers, such as adenoid cystic carcinoma, matrix-producing carcinoma, apocrine carcinoma and acinic cell carcinoma.

Molecular mechanisms of snoRNA-IL-15 crosstalk in adipocyte lipolysis and NK cell rejuvenation

Obesity, in which the functional importance of small nucleolar RNAs (snoRNAs) remains elusive, correlates with risk for many cancer types. Here, we identify that the serum copies of adipocyte-expressed SNORD46 correlate with body mass index (BMI), and serum SNORD46 antagonizes interleukin-15 (IL-15) signaling. Mechanically, SNORD46 binds IL-15 via G11, and G11A (a mutation that significantly enhances binding affinity) knockin drives obesity in mice. Functionally, SNORD46 blocks IL-15-induced, FER kinase-dependent phosphorylation of platelet glycoprotein 4 (CD36) and monoglyceride lipase (MGLL) in adipocytes, leading to inhibited lipolysis and browning. In natural killer (NK) cells, SNORD46 suppresses the IL-15-dependent autophagy, leading to reduced viability of obese NK. SNORD46 power inhibitors exhibit anti-obesity effects, concurring with improved viability of obese NK and anti-tumor immunity of CAR-NK cell therapy. Hence, our findings demonstrate the functional importance of snoRNAs in obesity and the utility of snoRNA power inhibitors for antagonizing obesity-associated immune resistance.

Trichorhinophalangeal syndrome type 1 (TRPS1) expression in male breast carcinoma

Currently, there is a paucity of highly specific and sensitive markers to identify breast carcinoma in male patients. Immunohistochemical stains commonly used for unmasking primary breast carcinomas include estrogen receptor (ER) and GATA3. However, these markers are commonly expressed in carcinomas originating from other organ systems and can be reduced in breast carcinomas with higher histologic grades. Androgen receptor (AR) may be used to highlight primary male breast cancer, but this marker can also be expressed in other carcinomas. We evaluated TRPS1, a highly sensitive and specific marker for female breast carcinoma, in cases of male breast carcinoma. Through an institutional database search, we identified 72 cases of primary invasive breast carcinoma in male patients. Among ER/progesterone receptor (PR)-positive cancers, 97% showed intermediate or high positivity for both TRPS1 and GATA3. Among HER2-positive cancers, 100% showed intermediate or high positivity for TRPS1 and GATA3. One case of triple-negative breast cancer was collected, showing high positivity for TRPS1 and negativity for GATA3. AR staining was non-specific and heterogeneous: 76% showed high positivity, but the remaining 24% showed low or intermediate positivity. Additionally, among 29 cases of metastatic carcinoma to male breast tissue, 93% were negative for TRPS1, and the remaining 2 cases (7%), which were carcinomas from salivary gland primary tumors, were intermediate positive. TRPS1 is a sensitive and specific marker in the unmasking of male primary invasive breast carcinoma across different subtypes. Additionally, TRPS1 is not expressed in metastatic carcinomas of multiple primaries, with the exception of salivary gland primaries.

Comparing the effectiveness of prolotherapy and percutaneous dry needling in the treatment of lateral epicondylitis: a retrospective cohort study

OBJECTIVE

Lateral epicondylitis (LE) can result in a functional loss in patients because of pain and has recently become more prevalent. This study compared the effects of minimally invasive prolotherapy (PRO) and percutaneous dry needling (PDN) on LE treatment.

PATIENTS AND METHODS

Patients were divided into three groups; Group 1 included patients undergoing PDN, Group 2 included those undergoing PRO, and Group 3 included those undergoing PDN+PRO. All these treatments were administered three times and at a 3-week interval in each patient. Data on the visual analog scale (VAS) and patient-rated tennis elbow evaluation (PRTEE) scale scores of the patients were collected at weeks 0, 3, and 6 and month 6 and retrospectively analyzed.

RESULTS

The VAS and PRTEE scores decreased in all groups. The decrease in Group 3 was higher than that in the other groups (p<0.001). Upon evaluating within-group differences in VAS and PRTEE scores, the scores at week 3, week 6, and month 6 gradually decreased compared with the baseline in all groups (p<0.001).

CONCLUSIONS

PDN and PRO are minimally invasive and can successfully treat LE. A combination of PDN+PRO provides better results than PDN or PRO alone. As the materials we used in these treatments are relatively inexpensive and readily available, we believe our study will help reduce the national healthcare costs allocated for the treatment of LE.

Mutations in Homologous Recombination Genes and Loss of Heterozygosity Status in Advanced-Stage Breast Carcinoma

Poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPis) have demonstrated antitumor activity in cancers with a homologous recombination deficiency (HRD) and have recently been approved by the FDA for the treatment of germline BRCA1/2-mutation-associated breast cancer. PARPis have also been found to be efficacious in BRCA wild-type (BRCAwt) lesions with high genomic loss of heterozygosity (LOH-high). The goal of this study was to retrospectively investigate the tumor mutations in homologous recombination (HRR) genes and the LOH score in advanced-stage breast carcinomas (BCs). Sixty-three patients were included in our study, 25% of whom had HRR gene mutations in their tumors, including 6% BRCA1/2 and 19% non-BRCA-containing gene mutations. An HRR gene mutation was associated with a triple-negative phenotype. Twenty-eight percent of the patients had an LOH-high score, which, in turn, was associated with a high histological grade, a triple-negative phenotype, and a high tumor mutational burden (TMB). Among the six patients who received PARPi therapy, one had a tumor with a PALB2 mutation other than BRCA and had a clinical partial response. Twenty-two percent of the LOH-low tumors had BRCAwt-HRR gene mutations, compared with 11% of the LOH-high tumors. Comprehensive genomic profiling revealed a subset of breast cancer patients with a BRCAwt-HRR gene mutation that would be missed by an LOH test. The necessity of next-generation sequencing coupled with HRR gene analysis for PARPi therapy requires further investigation in clinical trials.

Breast Cancer With a HER2 FISH Group 2 Result: Should HER2 Tests be Repeated?

BACKGROUND

Breast cancer with fluorescence in situ hybridization (FISH) group 2 pattern (HER2 <4 and HER2/CEP17 ratio ≥2, a subset of monosomy CEP17) was historically considered HER2-positive, but mostly HER2-negative according to updated 2018 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines unless 3+ by immunohistochemistry (IHC). Therapeutic relevance of this group remained elusive, therefore we assessed if repeat IHC and FISH can assist final HER2 classification.

PATIENT AND METHODS

We retrospectively reviewed HER2 FISH performed at our institution from 2014 to 2018 and identified 23 of 3554 (0.6%) breast cancer cases with at least one-time measurement of HER2 FISH categorized as group 2. Repeat HER2 tests were performed for cases with available alternative tumor samples and compared with initial testing following 2018 ASCO/CAP guidelines.

RESULTS

Only 1 of 23 group 2 cases was HER2-positive, 0/18 in primary and 1/5 in metastatic/recurrent tumors. Of 13 primary tumors with repeat HER2 results; 10 (77%) remained HER2-negative; 3 (23%) changed from HER2-negative (group 2 and IHC 2+) to HER2-positive (group 1 and IHC 2+). Among 8 of these 13 patients receiving neoadjuvant systemic therapy containing anti-HER2 agent, 3 (38%) achieved pathologic complete response (pCR). Two of 3 pCR cases were HER2-positive converters on repeat testing. Three pCR cases were ER-negative or -low positive and Ki67 ≥40%, while 5 partial responders were ER-positive and Ki67 <40% (P < .05).

CONCLUSION

Breast cancer with HER2 FISH group 2 result may represent heterogeneous populations of tumor cells being originated de novo or preferentially selected secondary to therapy. Repeat HER2 tests on alternative samples may be considered to guide anti-HER2 therapy.

Tumor-associated nonmyelinating Schwann cell-expressed PVT1 promotes pancreatic cancer kynurenine pathway and tumor immune exclusion

One of the major obstacles to treating pancreatic ductal adenocarcinoma (PDAC) is its immunoresistant microenvironment. The functional importance and molecular mechanisms of Schwann cells in PDAC remains largely elusive. We characterized the gene signature of tumor-associated nonmyelinating Schwann cells (TASc) in PDAC and indicated that the abundance of TASc was correlated with immune suppressive tumor microenvironment and the unfavorable outcome of patients with PDAC. Depletion of pancreatic-specific TASc promoted the tumorigenesis of PDAC tumors. TASc-expressed long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) was triggered by the tumor cell-produced interleukin-6. Mechanistically, PVT1 modulated RAF proto-oncogene serine/threonine protein kinase-mediated phosphorylation of tryptophan 2,3-dioxygenase in TASc, facilitating its enzymatic activities in catalysis of tryptophan to kynurenine. Depletion of TASc-expressed PVT1 suppressed PDAC tumor growth. Furthermore, depletion of TASc using a small-molecule inhibitor effectively sensitized PDAC to immunotherapy, signifying the important roles of TASc in PDAC immune resistance.

SOX17: A Highly Sensitive and Specific Immunomarker for Ovarian and Endometrial Carcinomas

PAX8 is the most commonly used immunomarker to link a carcinoma to the gynecologic tract; however, it lacks specificity. Through mining The Cancer Genome Atlas mRNA expression profile data, we identified SOX17 as a potential specific marker at the mRNA level for gynecologic tumors. To evaluate the utility of this marker in the identification of the gynecologic origin of a given carcinoma, we performed immunochemical staining in a large cohort of ovarian and endometrial cancer cases (n = 416), together with a large cohort of solid tumors from other organs (n = 1544) in tissue microarrays. Similar to PAX8, SOX17 was highly expressed in different subtypes of ovarian carcinoma (97.5% for SOX17 vs 97% for PAX8 in serous carcinoma, 90% vs 90% in endometrioid carcinoma, and 100% vs 100% in clear cell carcinoma), except for mucinous carcinoma (0% vs 27%), and was also highly expressed in different subtypes of endometrial carcinoma (88% vs 84% in endometrioid carcinoma, 100% vs 100% in serous and clear cell carcinoma). SOX17 was not expressed in thyroid and renal cell carcinomas, whereas PAX8 expression was high (86% and 85%, respectively). In addition, SOX17 was expressed at low levels in cervical adenocarcinoma (20%) and had no expression in cervical squamous carcinoma, mesothelioma, and carcinomas from the breast, lung, pancreas, colon, stomach, liver, bladder, and salivary gland. Our data indicate that SOX17 is not only a sensitive but also a specific marker for the origin of ovarian and endometrial carcinomas.

Reporting of Surgically Removed Lymph Nodes for Breast Tumors: Recommendations From the International Collaboration on Cancer Reporting

CONTEXT.—

The International Collaboration on Cancer Reporting (ICCR), supported by major pathology and cancer organizations, aims at the standardization of evidence-based pathology reporting of different types of cancers, with the inclusion of all parameters deemed to be relevant for best patient care and future data collection. Lymph node metastasis is one of the most important prognostic factors in breast cancer.

OBJECTIVE.—

To produce a histopathology reporting guide by a panel of recognized experts from the fields of pathology and surgery with elements deemed to be core (required) and noncore (recommended) to report when assessing regional lymph nodes of patients with breast cancer.

DATA SOURCES.—

Published literature, previous guidelines/recommendations, and current cancer staging principles were the basis of the data set drafted by the expert panel. This was discussed in a series of teleconferences and email communications. The draft data set was then made available for public consultation through the ICCR Web site. After this consultation and ICCR ratification, the data set was finalized.

CONCLUSIONS.—

The ICCR has published a data set for the reporting of surgically removed lymph nodes (including sentinel lymph node biopsy, axillary lymph node dissection, targeted axillary surgery, and lymph node sampling specimens) for breast tumors. This is part of a series of 4 ICCR breast cancer-related data sets. It includes 10 core elements along with 2 noncore elements. This should allow for synoptic reporting, which is more precise, uniform, and complete than nonsynoptic reporting, and leads to improved patient outcomes.

Metastatic non-Hematopoietic Neoplasms to the Breast: A Study of 238 Cases

AIMS

The aim of this study was to review the clinicopathologic characteristics of metastatic non-hematopoietic malignancies to the breast, in order to identify salient features for practicing pathologist that are useful in distinguishing metastatic lesions from primary breast neoplasms.

METHODS AND RESULTS

A total of 238 cases were identified during the period from January 2005 to January 2015. Clinicopathologic features of these cases were retrospectively reviewed. Primary tumors included melanoma (99, 42%), serous carcinoma (35, 15%), neuroendocrine neoplasm (32, 13%), sarcoma (23, 10%), and adenocarcinoma from various organs (47, 20%), among others. Most metastases were unilateral (223, 94%) and unifocal (206, 87%), and were detected radiographically (167, 70%). Concurrent ipsilateral axillary metastasis occurred in 33 (14%) patients. Among 238 cases, 41 had metastatic disease to the breast concurrently or preceding the primary cancer diagnosis. Notable, in 39 (16%) cases, breast metastasis was the first clinical presentation of disease, and 16 (41%) of these cases were initially misdiagnosed as breast primaries. In contrast, with known history of non-mammary primary tumors, only 4 of 197 (2%) cases were misdiagnosed (p<0.0001).

CONCLUSIONS

Metastatic tumors share many overlapping features with breast primary carcinomas. However, cases with a well-circumscribed tumor, lack of in situ component, ER/PR negativity, and unusual morphologic features should raise the consideration of metastatic disease. While clinical history is paramount for correct diagnosis, metastasis to the breast as the first clinical presentation is not uncommon.

The role of three dimensional transesophageal echocardiography novel score in the success of redo percutaneous mitral balloon valvuloplasty

Funding Acknowledgements

Type of funding sources: None.

Background

Mitral valve morphology is traditionally evaluated according to the images of two-dimensional transthoracic echocardiography and Wilkins score (WS) criteria in the selection of suitable patients for Percutaneous balloon mitral valvuloplasty (PBMV).  However, WS does not include mitral commissural morphology, it is known that not only WS but mitral valve commissure morphology is also important in the success of PBMV. It is known that mitral stenosis might develop secondary to the progression of the disease in the follow-up of the patients after first PBMV, and there are a limited knowledge about outcome and success in terms of redo PBMV.

Purpose

We aimed to determine whether WS in redo PMBV is sufficient in the success of procedure and additionally we have evaluated a novel scoring system including three dimensional (3D) transesophageal echocardiography (TEE) of the mitral valve structure before redo PBMV in terms of success of the procedure.

Methods

Our study designed as a retrospective, single center study. Fifty patients who underwent redo PMBV were included in the study. The patients were divided into two groups according to the success of the Redo PMBV procedure which was defined as post-procedural Mitral valve area (MVA) ≥ 1.5 cm2 and post-procedural mitral regurgitation less than moderate by echocardiographic evaluation immediately after Redo PMBV. A novel score based on 3D TEE findings was created by analyzing the images recorded before Redo PMBV and by evaluating the mitral commissure and calcification. The role of traditional WS and novel score in the success of the procedure were investigated.

Results

In the study group, 36 patients (72%) had successful redo PMBV procedure. WS was 8 (IQR 7 - 9) and novel 3D TEE score was found 4 (IQR 3 - 4) in the whole study group. While no statistically significant relationship was found between WS and procedural success (p = 0.187), a statistically significant relationship was found between novel 3D TEE score and procedural success (p = 0.042). According to these findings; when both models were compared, the predictive accuracy and performance of the model developed with novel 3D TEE score to predict procedural success was found to be more favorable than the model developed with WS. When the probability of procedural success was calculated according to novel 3D TEE score using univariable logistic regression analysis, the probability of procedural successes was calculated &gt; 90%, especially when novel 3D TEE score was &lt;4. 

Conclusion

The novel 3D TEE score might be an informative scoring system in the selection of suitable patients for successful redo PMBV, especially in patients who are considered for surgery due to the high WS. Abstract Figure. Definition of novel 3D TEE scoring  Abstract Figure. Information about novel 3D TEE scoring

A 95-gene signature stratifies recurrence risk of invasive disease in ER-positive, HER2-negative, node-negative breast cancer with intermediate 21-gene signature recurrence scores

PURPOSE

A subset of patients with intermediate 21-gene signature assay recurrence score may benefit from adjuvant chemoendocrine therapy, but a predictive strategy is needed to identify such patients. The 95-gene signature assay was tested to stratify patients with intermediate RS into high (95GC-H) and low (95GC-L) groups that were associated with invasive recurrence risk.

METHODS

Patients with ER-positive, HER2-negative, node-negative breast cancer and RS 11-25 who underwent definitive surgery and adjuvant endocrine therapy without any cytotoxic agents were included. RNA was extracted from archived formalin-fixed, paraffin-embedded samples, and 95-gene signature was calculated.

RESULTS

206 patients had RS of 11-25 (95GC-L, N = 163; 95GC-H, N = 43). In Cox proportional hazards model, 95GC-H was significantly associated with shorter time to recurrence than was 95GC-L (HR 5.94; 95%CI 1.81-19.53; P = 0.005). The correlation between 95-gene signature and 21-gene signature assay scores was not strong (correlation coefficient r = 0.27), which might suggest that 95-gene signature reflects biological characteristics differing from what 21-gene signature shows.

CONCLUSIONS

The 95-gene signature stratifies patients with ER-positive, HER2-negative, node-negative invasive breast cancer and intermediate RS of 11-25 into high and low groups that are associated with recurrence risk of invasive disease. Further retrospective analysis in the prospectively accrued TAILORx population is warranted to confirm that 95-gene signature can identify patients who would benefit from adjuvant chemoendocrine therapy.

Targeting Replicative Stress and DNA Repair by Combining PARP and Wee1 Kinase Inhibitors Is Synergistic in Triple Negative Breast Cancers with Cyclin E or BRCA1 Alteration

Simple Summary

Triple-negative breast cancer (TNBC) is a subtype of invasive breast cancer with an aggressive phenotype that has decreased survival compared with other types of breast cancers, due in part to the lack of biomarker driven targeted therapies. Here, we show that breast cancer patients whose tumors show high levels of cyclin E expression have a higher prevalence of BRCA1/2 alterations and have the worst clinical outcomes. In vitro and in vivo studies revealed that combination therapies with poly (ADP-ribose) polymerase (PARP) and Wee1 kinase inhibitors in TNBC cells with either BRCA1 mutations or high levels of cyclin E results in synergistic cell death due to induction of replicative stress and downregulation of DNA repair. These studies suggest that by preselecting patients whose tumors have high cyclin E levels or harbor mutations in BRCA1, only those cases with the highest replicative stress properties will be subjected to combination treatment and likely result in synergistic activity of the two agents.

Abstract

The identification of biomarker-driven targeted therapies for patients with triple negative breast cancer (TNBC) remains a major clinical challenge, due to a lack of specific targets. Here, we show that cyclin E, a major regulator of G1 to S transition, is deregulated in TNBC and is associated with mutations in DNA repair genes (e.g., BRCA1/2). Breast cancers with high levels of cyclin E not only have a higher prevalence of BRCA1/2 mutations, but also are associated with the worst outcomes. Using several in vitro and in vivo model systems, we show that TNBCs that harbor either mutations in BRCA1/2 or overexpression of cyclin E are very sensitive to the growth inhibitory effects of AZD-1775 (Wee 1 kinase inhibitor) when used in combination with MK-4837 (PARP inhibitor). Combination treatment of TNBC cell lines with these two agents results in synergistic cell killing due to induction of replicative stress, downregulation of DNA repair and cytokinesis failure that results in increased apoptosis. These findings highlight the potential clinical application of using cyclin E and BRCA mutations as biomarkers to select only those patients with the highest replicative stress properties that may benefit from combination treatment with Wee 1 kinase and PARP inhibitors.

TRPS1: a highly sensitive and specific marker for breast carcinoma, especially for triple-negative breast cancer

Currently there is no highly specific and sensitive marker to identify breast cancer-the most common malignancy in women. Breast cancer can be categorized as estrogen receptor (ER)/progesterone receptor (PR)-positive luminal, human epidermal growth factor receptor 2 (HER2)-positive, or triple-negative breast cancer (TNBC) types based on the expression of ER, PR, and HER2. Although GATA3 is the most widely used tumor marker at present to determine the breast origin, which has been shown to be an excellent marker for ER-positive and low-grade breast cancer, but it does not work well for TNBC with sensitivity as low as <20% in metaplastic breast carcinoma. In the current study, through TCGA data mining we identified trichorhinophalangeal syndrome type 1 (TRPS1) as a specific gene for breast carcinoma across 31 solid tumor types. Moreover, high mRNA level of TRPS1 was found in all four subtypes of breast carcinoma including ER/PR-positive luminal A and B types, HER2-positive type, and basal-type/TNBC. We then analyzed TRPS1 expression in 479 cases of various types of breast cancer using immunochemistry staining, and found that TRPS1 and GATA3 had comparable positive expression in ER-positive (98% vs. 95%) and HER2-positive (87% vs. 88%) breast carcinomas. However, TRPS1 which was highly expressed in TNBC, was significantly higher than GATA3 expression in metaplastic (86% vs. 21%) and nonmetaplastic (86% vs. 51%) TNBC. In addition, TRPS1 expression was evaluated in 1234 cases of solid tumor from different organs. In contrast to the high expression of GATA3 in urothelial carcinoma, TRPS1 showed no or little expression in urothelial carcinomas or in other tumor types including lung adenocarcinoma, pancreatic adenocarcinoma, colon and gastric adenocarcinoma, renal cell carcinoma, melanoma, and ovarian carcinoma. These findings suggest that TRPS1 is a highly sensitive and specific marker for breast carcinoma and can be used as a great diagnostic tool, especially for TNBC.

Anti-GD2 antibody dinutuximab inhibits triple-negative breast tumor growth by targeting GD2+ breast cancer stem-like cells

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with no effective standard therapy. Breast cancer stem-like cells (BCSCs) in primary TNBCs are reported to be responsible for metastatic spread of the disease and resistance to chemotherapy, but no available therapeutic tools target BCSCs. We previously reported that the ganglioside GD2 is highly expressed on BCSCs and that inhibition of its expression hampers TNBC growth. We therefore hypothesized that the anti-GD2 antibody dinutuximab (ch14.18) targets GD2+ BCSCs and inhibits TNBC growth.

METHOD

To test our hypothesis, we first determined GD2 expression via immunohistochemistry in frozen primary tumor samples from patients with TNBC (n=89). Then, we examined the effects of dinutuximab on TNBC cell adhesion, migration, and mammosphere formation in vitro and on tumor growth in vivo using TNBC cell-line and patient-derived xenograft (PDX) models.

RESULTS

We found that GD2 was expressed in around 60% of primary TNBC tumors at variable levels and was associated with worse overall survival of patients with TNBC (p=0.002). GD2 was found to be expressed in tumors and stroma, but normal ducts and lobules in adjacent tissues have shown low or no GD2 staining, indicating that GD2 is potentially a novel biomarker for tumor and its microenvironment. Treatment with dinutuximab significantly decreased adhesion and migration of MDA-MB-231 and SUM159 TNBC cells. Moreover, dinutuximab treatment inhibited mTOR signaling, which has been shown to be regulated by GD2 in BCSCs. Dinutuximab also reduced tumor growth in nude mice bearing TNBC cell-line xenografts. Finally, dinutuximab in combination with activated natural killer cells inhibited tumor growth in a TNBC PDX model and improved overall survival of tumor-bearing mice.

CONCLUSIONS

Dinutuximab successfully eliminated GD2+ cells and reduced tumor growth in both in vivo models. Our data provide proof-of-concept for the criticality of GD2 in BCSCs and demonstrate the potential of dinutuximab as a novel therapeutic approach for TNBC.

Prospective Registry Trial Assessing the Use of Magnetic Seeds to Locate Clipped Nodes After Neoadjuvant Chemotherapy for Breast Cancer Patients

BACKGROUND

Targeted axillary dissection (TAD) involves locating and removing both clipped nodes and sentinel nodes for assessment of the axillary response to neoadjuvant chemotherapy (NAC) by clinically node-positive breast cancer patients. Initial reports described radioactive seeds used for localization, which makes the technique difficult to implement in some settings. This trial was performed to determine whether magnetic seeds can be used to locate clipped axillary lymph nodes for removal.

METHODS

This prospective registry trial enrolled patients who had biopsy-proven node-positive disease with a clip placed in the node and treatment with NAC. A magnetic seed was placed under ultrasound guidance in the clipped node after NAC. All the patients underwent TAD.

RESULTS

Magnetic seeds were placed in 50 patients by 17 breast radiologists. All the patients had successful seed placement at the first attempt (mean time for localization was 6.1 min; range 1-30 min). The final position of the magnetic seed was within the node (n = 44, 88%), in the cortex (n = 3, 6%), less than 3 mm from the node (n = 2, 4%), or by the clip when the node could not be adequately visualized (n = 1, 2%). The magnetic seed was retrieved at surgery from all the patients. In 49 (98%) of the 50 cases, the clip and magnetic seed were retrieved from the same node. Surgeons rated the transcutaneous and intraoperative localization as easy for 43 (86%) of the 50 cases. No device-related adverse events occurred.

CONCLUSIONS

Localization and selective removal of clipped nodes can be accomplished safely and effectively using magnetic seeds.

Effectiveness and Safety of Magseed-localization for Excision of Breast Lesions: A Prospective, Phase IV Trial

OBJECTIVE

A prospective, phase IV study was conducted to assess the effectiveness of Magseed to localize breast lesions requiring surgical excision.

BACKGROUND

Since FDA approval in 2016, Magseed has been increasingly used to localize non-palpable lesions due to advantages over wires or radioactive seeds. This is the first prospective, post marketing trial of Magseed.

METHODS

From 1/2017-2/2018, 107 women with lesions requiring localization were enrolled at a single institution. Primary endpoint was Magseed retrieval rate. Secondary endpoints were adverse events, accuracy of placement, surgery duration and positive margin rate. Clinicians were surveyed for ease of use using a Likert scale. Descriptive statistics and Fisher's exact test were performed to assess univariable associations with positive margins.

RESULTS

There were 124 Magseeds placed including one marker in 93 subjects, 2 markers in 11 and 3 markers in 3. The majority of lesions were masses (63%) followed by calcifications (24%). All 124 Magseeds were placed within 10mm of the target lesion and surgically retrieved with median operative time of 15min (range 4-47). No device-related adverse events occurred. Of the 98 malignant lesions, 9 had positive margins and 7 of them underwent a second surgery for additional margins. On univariable analysis, age ≤ 50 (25.0% vs 6.4%, p=0.04), lesion histology (p = 0.03), and pathologic T-stage (p = 0.04) were significantly associated with positive margins. Clinicians rated the Magseed very or fairly easy to use in most cases.

CONCLUSIONS

The Magseed system for localization of non-palpable lesions was effective and safe; all markers were successfully retrieved with margin-negative resections in 91%. This study supports use of Magseed for localization of breast lesions.

Rate of reclassification of HER2-equivocal breast cancer cases to HER2-negative per the 2018 ASCO/CAP guidelines and response of HER2-equivocal cases to anti-HER2 therapy

Purpose

The 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guideline on HER2 testing in breast cancer permits reclassification of cases with HER2-equivocal results by FISH. The impact of such reclassification is unclear. We sought to determine the proportion of HER2-equivocal cases that are reclassified as HER2-negative and the impact of anti-HER2 therapy on survival in HER2-equivocal cases.

Methods

We reviewed medical records of breast cancer patients who had HER2 testing by fluorescence in stitu hybridization (FISH) and immunohistochemistry (IHC) performed or verified at The University of Texas MD Anderson Cancer Center during April 2014 through March 2018 and had equivocal results according to the 2013 ASCO/CAP guideline. The population was divided into 2 cohorts according to whether the biopsy specimen analyzed came from primary or from recurrent or metastatic disease. HER2 status was reclassified according to the 2018 ASCO/CAP guideline. Overall survival (OS) and event-free survival (EFS) were calculated using the Kaplan-Meier method, and the relationship between anti-HER2 therapy and clinical outcomes was assessed.

Results

We identified 139 cases with HER2-equivocal results according to the 2013 ASCO/CAP guideline: 90 cases of primary disease and 49 cases of recurrent/metastatic disease. Per the 2018 ASCO/CAP guideline, these cases were classified as follows: overall, HER2-negative 112 cases (80%), HER2-positive 1 (1%), and unknown 26 (19%); primary cohort, HER2-negative 85 (94%), HER2-positive 1 (1%), unknown 4 (4%); and recurrent/metastatic, HER2-negative 27 (55%) and unknown 22 (45%). Five patients in the primary-disease cohort and 1 patient in the recurrent/metastatic-disease cohort received anti-HER2 therapy. There was no significant association between anti-HER2 therapy and OS or EFS in either cohort (primary disease: OS, p = 0.67; EFS, p = 0.49; recurrent/metastatic-disease, OS, p = 0.61; EFS, p = 0.78.

Conclusions

The majority of HER2-equivocal breast cancer cases were reclassified as HER2-negative per the 2018 ASCO/CAP guideline. No association between anti-HER2 therapy and OS or EFS was observed. HER2-equivocal cases seem to have clinical behavior similar to that of HER2-negative breast cancers.

Challenges With the 8th Edition of the AJCC Cancer Staging Manual for Breast, Testicular, and Head and Neck Cancers

Three experts discussed changes in the 8th edition of the AJCC Cancer Staging Manual and challenges regarding these changes for staging of breast cancer, testicular cancer, and head and neck cancer, respectively. In general, the staging changes for breast cancer and for human papillomavirus-positive oropharyngeal cancer were hailed as improvements, but the changes for testicular cancer were questioned as to their clinical relevance. Better studies are needed to improve staging for human papillomavirus-negative oropharyngeal cancer.

Abstract P3-08-38: Primary cutaneous melanoma of the breast in women. A retrospective study of 82 patients

Background: Primary cutaneous melanoma of the breast (PCMB) is a relatively uncommon type of melanoma staged according to the AJCC system for other cutaneous melanomas. However, whether their outcome is different from primary cutaneous melanomas of other sun-exposed sites and the features that predict outcome specifically in PCMB are currently unclear. Moreover, histologically, the breast skin is considered to be a special site for melanocytic lesions. Therefore, we analyzed a retrospective cohort of female PCMB patients to determine the clinical and primary tumor features that correlate with time-to-event outcomes of overall survival (OS) and disease specific survival (DSS).

Design: We identified women with PCMB diagnosed and/or treated at our institution between 2002 and 2015. The following data were collected: clinical/ demographic features (age at diagnosis, ethnicity, anatomic site [nipple-areolar complex, upper, lower, medial, lateral]); primary tumor pathologic features (Breslow thickness, Clark level, ulceration, mitotic rate, vertical growth phase (VGP), regression, lymphovascular invasion (LVI), perineural invasion (PNI), tumor infiltrating lymphocytes (TIL) and cytology); and metastatic disease features (satellitosis, date and metastasis to sentinel and/or regional lymph nodes, clinical detectability of nodal metastasis, and date and site of distant metastases). Kaplan Meier methods, univariate and multivariate Cox proportional hazards regression models determined associations with OS and DSS.

Results: 82 cases, including 16 in-situ and 66 invasive PCMBs were identified. Most patients were white (98%), with a median age at diagnosis of 40.5 years (range: 15-77). With a median follow up of 7.6 years, the 1, 3, 5, 10-year OS rates were 97.4%, 94.7%, 91.9% and 81.3%, respectively; the 1, 3, 5, 10-year DSS rates were 98.7%, 95.9%, 93.1% and 86.9%, respectively; the median OS and DSS were not reached. Thirteen patients developed metastasis: 5 regional only, 1 distant only and 7 both; of which 6 had metastatic disease at presentation. Eleven patients died, and 8 was due to progression of PCMB. Most of the invasive PCMB were of superficial spreading type (84.8%), with median tumor thickness of 0.47 mm. Univariate analysis of patients with invasive melanoma revealed the following features to be associated with shorter survival (Table 1): age at presentation, Breslow thickness, Clark level, ulceration, mitotic rate and VGP; while histologic type, anatomic site, LVI, PNI, regression, associated nevus, cytology, and TIL were not significant. Adjusting covariate of features significant in univariate analysis, the multivariate analysis demonstrated only Breslow thickness and ulceration to be independently associated with OS and DSS.

Conclusion: Primary cutaneous melanomas of the breast often affects white adult women and increasing tumor thickness and ulceration are associated with shorter survival, similar to primary melanomas of other cutaneous sites.

Table 1: Clinical and Primary Tumor Features Associated with Overall (OS) and Disease Specific Survival (DSS) in Primary Cutaneous Melanomas of the BreastUnivariate Analysis (p-value)Clinical/ primary tumor featureOSDSSAge at presentation ≥ 41.5 years0.0020.018Breslow Thickness0.0020.001Clark Level0.0040.003Vertical Growth Phase0.0430.038Mitotic Rate0.001&lt;0.001Ulceration&lt;0.001&lt;0.001Regression0.2870.195Tumor Infiltrating Lymphocytes0.1370.278Lymphovascular Invasion0.1980.147Associated Nevus0.830.41Predominant Cytology0.7280.874Multivariate Analysis (p-value)Breslow Thickness0.0140.006Ulceration0.0060.017

Citation Format: Madhuchhanda Roy, Junsheng Ma, Aysegul A Sahin, Senthilkumar Damodaran, Michael T Tetzlaff, Jonathan L Curry, Ana M Ciurea, Jing Ning, Carlos A Torres-Cabala, Doina Ivan, Phyu P Aung, Merrick I Ross, Jeffrey E Gershenwald, Michael A Davies, Victor G Prieto and Priyadharsini Nagarajan. Primary cutaneous melanoma of the breast in women. A retrospective study of 82 patients [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 P3-08-38.

Abstract P4-10-22: Loss of androgen receptor after neoadjuvant anti-HER2 therapy in patients with locally advanced HER2-positive breast cancer

Background.Androgen receptor (AR) is widely expressed in different breast cancer subtypes. AR plays an important role in promoting the growth of HER2 +  breast cancer through cross-talk with HER2 signaling, including WNT7B upregulation, beta-catenin activation, stimulation of HER3 gene transcription, and promotion of HER2/HER3 heterodimerization. Preclinical data have shown that inhibiting AR with enzalutamide results in decreased HER2 phosphorylation and activation of ERK and AKT, without affecting HER2 and HER3 expression; however, the role that inhibiting HER2 with anti-HER2 therapy plays in AR expression and regulation is still unknown. In this study, we sought to identify the influence of anti-HER2 therapy on AR and estrogen receptor (ER) expression after neoadjuvant treatment in patients with locally advanced HER2+ breast cancer. Methods.We retrospectively collected data from 68 patients with locally advanced HER2+ breast cancer who received neoadjuvant treatment with trastuzumab and chemotherapy. AR and ER levels were determined by immunohistochemistry in available initial biopsy specimens and in surgical specimens of all patients with residual disease after neoadjuvant therapy. AR was assessed by Immunohistochemistry (IHC) staining using AR441 antibody from DAKO. Expression in &gt;10% of cells was considered positive. Pathological complete response (pCR) was defined as ypT0/is, ypN0. ROC curve analysis was performed to identify the correlation between AR score and pCR. Results.Twenty-five patients had pretreatment tissue available. Eighteen (72%) were positive for AR staining and 20 (80%) for ER staining. Of the 25 cases, 10 (40%) achieved a pCR and 15 (60%) did not. The median AR score for those with a pCR was higher, 20 (range 0, 80) vs 10 (range 0, 70). The area under the ROC curve was 0.59 (95% confidence interval 0.35, 0.83); we found no statistically significant relationship between AR score and pCR (p = 0.47). All nine cases positive for AR before neoadjuvant therapy who had residual tissue for staining after therapy had negative AR staining after neoadjuvant anti-HER2 therapy. Of 18 cases positive for ER before neoadjuvant therapy who had residual tissue for staining after therapy, only 6 (33%) had negative ER staining after neoadjuvant anti-HER2 therapy. Further, all patients initially positive for AR and ER remained ER positive but were AR negative after therapy. Conclusions. We found that in 100% of cases AR positivity disappeared after anti-HER2 neoadjuvant therapy in patients with residual disease, whereas ER positivity disappeared in only 33% of cases, suggesting that blocking HER2 may inhibit positive feedback with AR; however, both AR and ER receptors have independent biological interactions with HER2 that need to be explored. We plan to confirm our results with a larger sample size, and we will continue to monitor our patients to determine the influence of AR negativity after neoadjuvant anti-HER2 therapy on disease-free and overall survival.

Citation Format: Jose Rodrigo Espinosa Fernandez, Aysegul A. Sahin, Kenneth R. Hess, Raul Gerardo Ramirez Medina, Paula Anel Cabrera Galeana, Alejandro Javier España Ferrufino, Nereida Esparza Arias, Juan Enrique Bargallo Rocha, José Antonio García Gordillo, Gerardo Emmanuel Lopez Muñiz, Naoto T Ueno. Loss of androgen receptor after neoadjuvant anti-HER2 therapy in patients with locally advanced HER2-positive breast cancer [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 P4-10-22.

MicroRNA-17 acts as a tumor chemosensitizer by targeting JAB1/CSN5 in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the breast cancer subtype with the poorest prognosis. Evidence indicates that aberrant JAB1/CSN5 expression is associated with advanced tumor stage and poor prognosis in breast cancer. In this study, we evaluated expression of JAB1 in TNBC and potential mechanisms regulating this expression. We found that miR-17 expression was lower in TNBC than in normal breast tissue, and miR-17 expression in patients with TNBC was associated with a good prognosis. Furthermore, JAB1 expression was regulated by miR-17 in TNBC cells, and mice with miR-17-overexpressing tumors had less tumor growth and lower tumor JAB1 expression than control mice. We also demonstrated that miR-17 suppressed JAB1's oncogenic function, leading to tumor growth inhibition and sensitizing TNBC cells to chemotherapy treatment. JAB1 knockdown in TNBC cells mimicked the effect of miR-17 overexpression and led to significant decreases in cell proliferation, colony formation, and migration, increased p27 expression, and enhanced cisplatin sensitivity. Our findings suggest that miR-17 acts as a tumor suppressor by directly targeting JAB1 in TNBC; this may lead to novel therapeutic targets and strategies for treating TNBC patients.

Abstract 323: Combined inhibition of STAT-3 & DNA repair in palbociclib resistant breast cancer

The CDK4/6 inhibitor palbociclib is currently being used in combination with endocrine therapy to treat advanced ER positive breast cancer patients. While this treatment has shown great promise in the clinic, about 25-35% of the patients do not respond initially, and almost all patients eventually acquire resistance. Hence, understanding the mechanisms of acquired resistance to CDK4/6 inhibition is crucial to devise alternate treatment strategies.

To identify mechanisms of resistance to CDK4/6 inhibition we developed MCF-7 and T47D palbociclib resistant cells in a step-wise manner by gradually increasing concentrations of palbociclib. These cells are not only resistant to palbociclib, but exhibited resistance to the other approved CDK4/6 inhibitors; ribociclib and abemaciclib. Additionally, we assessed if these resistant cells have an altered response to endocrine therapy and observed that these cells are also resistant to treatment with tamoxifen or fulvestrant by about 16-fold. Multi-omics analyses revealed enrichment of pathways known to regulate EMT and promote stem-like properties, as well as, downregulation of estrogen response and DNA repair pathways.

Palbociclib resistant cells exhibited mammosphere formation and CD44high/CD24low population indicating the presence of increased breast cancer stem cell-like cells (B-CSC-L). Given the recently elucidated role of IL-6/STAT-3 mediated B-CSC-L phenotypes in drug resistance, we examined IL-6 mRNA levels, which increased by &gt;12-fold in the resistant cells. Treatment with STAT-3 inhibitors, napabucasin and C188-9, significantly decreased the B-CSC-L population and mammosphere formation, indicating a crucial role for the IL-6/STAT-3 pathway in driving B-CSC-L phenotype and palbociclib resistance.

Since DNA repair pathways were collectively downregulated in the palbociclib resistant cells, we examined their sensitivity to DNA damaging agents. Results showed that resistant cells were more sensitive to olaparib (PARP inhibition), with no effect on B-CSC-L population. Next, we examined if combined treatment with agents targeting STAT-3 and PARP would be synergistic in palbociclib resistant cells. Results show that combined treatment with olaparib and napabucasin or C-1889 significantly decreased B-CSC-L population, colony formation and increased cell death via apoptosis, when compared to no-treatment or single treatment controls of the palbociclib resistant cells.

Lastly, we interrogated matched tumor samples from breast cancer patients who progressed on palbociclib for deregulation of estrogen receptor, DNA repair, and IL-6/STAT3 signaling and found that these pathways are altered as compared to the pre-treatment samples.

Taken together, the results show that targeting IL-6/STAT-3 mediated cancer stem cells and DNA repair deficiency by PARP inhibitors in combination can effectively treat acquired resistance to palbociclib.

Citation Format: Nicole M. Kettner, Smruthi Vijayaraghavan, Merih Guray Durak, Tuyen Bui, Mehrnoosh Kohansal, Min Jin Ha, Bin Liu, Xiayu Rao, Jing Yang, Min Yi, Jason P. Carey, Xian Chen, T. Kris Eckols, Akshara S. Raghavendra, Nuhad K. Ibrahim, Meghan Karuturi, Stephanie S. Watowich, Aysegul A. Sahin, David J. Tweardy, Kelly K. Hunt, Debu Tripathy, Khandan Keyomarsi. Combined inhibition of STAT-3 & DNA repair in palbociclib resistant breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 323.

Sphingosine Kinase 1 Signaling Promotes Metastasis of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. To identify TNBC therapeutic targets, we performed integrative bioinformatics analysis of multiple breast cancer patient-derived gene expression datasets and focused on kinases with FDA-approved or in-pipeline inhibitors. Sphingosine kinase 1 (SPHK1) was identified as a top candidate. SPHK1 overexpression or downregulation in human TNBC cell lines increased or decreased spontaneous metastasis to lungs in nude mice, respectively. SPHK1 promoted metastasis by transcriptionally upregulating the expression of the metastasis-promoting gene FSCN1 via NFκB activation. Activation of the SPHK1/NFκB/FSCN1 signaling pathway was associated with distance metastasis and poor clinical outcome in patients with TNBC. Targeting SPHK1 and NFκB using clinically applicable inhibitors (safingol and bortezomib, respectively) significantly inhibited aggressive mammary tumor growth and spontaneous lung metastasis in orthotopic syngeneic TNBC mouse models. These findings highlight SPHK1 and its downstream target, NFκB, as promising therapeutic targets in TNBC. SIGNIFICANCE: SPHK1 is overexpressed in TNBC and promotes metastasis, targeting SPHK1 or its downstream target NFκB with clinically available inhibitors could be effective for inhibiting TNBC metastasis.

The impact of Ki-67 in the context of multidisciplinary care in primary inflammatory breast cancer

Background: Research on the prognostic or predictive value of Ki-67 among patients with inflammatory breast cancer (IBC) is limited.

Methods: Using the comprehensive database of the Morgan Welch Inflammatory Breast Cancer Research Program at MD Anderson Cancer Center, we identified a cohort of breast cancer patients who were diagnosed with IBC between 1992 and 2012. Distributions of survival outcomes were estimated by the Kaplan-Meier method and compared by log-rank tests and Cox models.

Results: Among a total of 257 patients with stage III IBC, the mean percentage of tumor cells that stained positive for Ki-67 was 48%, (range, 4% to 100%). Using a cutoff of 20% as being Ki-67 positive, this characteristic tended to be associated with worse overall survival (p=0.07) in the univariate analysis. After controlling for hormone receptor (HR) status, human epidermal growth factor receptor 2 (HER2) status and having received trimodality treatment, the association between Ki-67 status and overall survival remained marginally significant (p=0.07). The effects of trimodality treatment on overall survival were statistically significantly different between patients with Ki-67-positive tumors (hazard ratio=0.26, 95% confidence interval [CI]=0.15-0.44, p<0.01) and those with Ki-67-negative tumors (hazard ratio =2.04, 95% CI=0.45-9.29, p=0.36) after adjusting for other tumor characteristics (p=0.01).

Conclusion: IBC patients with Ki-67-positive tumors tended to have worse overall survival, but were more likely to benefit from trimodality treatment, with better overall survival and distant metastasis-free survival. Patients with Ki-67-negative tumors had similar survival distributions, regardless of whether they received trimodality treatment.

Evaluation of predictive biomarkers for AR therapy and to identify the LAR subtype of TNBC

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Background: Androgen-receptor-like (LAR) triple-negative breast cancer (TNBC) is a subtype identified using Vanderbilt’s molecular signature. LAR subtype has the lowest pCR rate for NACT among all TNBC subtypes (10% vs. 28% for TNBC in general). We launched a clinical trial to determine the effectiveness of enzalutamide and paclitaxel (ZT) in improving this poor chemo. response in the neoadjuvant setting for pts with anthracycline-refractory, androgen receptor (AR)+ TNBC (NCT02689427). However, we do not yet have a robust predictive biomarker to detect an activated AR pathway and have not seen a robust correlation between molecular LAR subtype and AR IHC staining intensity. Methods: Molecular profiling and immunohistochemical analysis of key biomarkers (LAR, Ki67, and vimentin) was performed for all pts enrolled in A Randomized triple negative breast cancer enrolling Trial to Confirm Molecular Profiling Improves Survival (ARTEMIS; NCT02276443). Patients receive 4 cycles of AC, followed by an experimental arm or standard taxane, tailored using nuclear IHC staining. IHC staining of ≥30% AR+ was used as a threshold for selection for enzalutamide combination arm. We evaluated the concordance between LAR-subtype using molecular profiling vs % AR+ cells via IHC. Results: As part of the clinical trial, tumors with ≥30% AR+ cells were classified as LAR. In addition, we used RNA profiling to assign Vanderbilt subtype scores, resulting in classification of 15 tumors as LAR+. We observed a significant correlation (r=0.75) between LAR score and %AR+ cells, with 13 of 15 LAR tumors having ≥30% AR+ cells. Among patients with high % of AR+ tumor cells, 11 received enzalutamide, with 43% (3/7) having responses (pCR or RCB-I). Conclusions: Comparison on numerical scores for Vanderbilt subtype and IHC scores suggests ≥30% AR+ IHC staining as the threshold (ppv=0.65, npv=0.98, Table) to identify the molecular LAR subtype. We observed a trend where response rate was higher in patients with ≥ AR+ IHC scores treated with enzalutamide; however, these results need confirmation in a larger cohort of patients. Clinical trial information: NCT02689427, NCT02276443. [Table: see text]

A novel 95-gene signature (Curebest 95GC Breast) that predicts recurrence-risk in patients with ER-positive, HER2-negative, node-negative, early-stage primary invasive breast cancer with an intermediate Oncotype DX Recurrence Score

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Background: The TAILORx trial demonstrated that adjuvant endocrine and chemoendocrine therapies had similar efficacy in patients with hormone receptor-positive, HER2-negative, node-negative breast cancer with an Oncotype DX recurrence score (RS) of 11-25. However, a predictive strategy is needed to identify patients with intermediate RS who may benefit from adjuvant chemoendocrine therapy. Curebest 95GC Breast (95GC) is a 95-gene signature that can stratify patients into two groups with high (95GC-H) and low (95GC-L) groups to predict the risk of recurrence. Our primary objective was to show that 95GC can classify patients with intermediate RS into binary recurrence risk groups. Methods: Patients with ER-positive, HER2-negative, node-negative invasive breast cancer and RS 11-30 who underwent definitive surgery and adjuvant endocrine therapy were included. RNA was derived from archived formalin-fixed, paraffin-embedded samples, and 95GC was calculated as reported previously. The Fisher exact and Brunner-Munzel tests were used to compare variables between 95GC groups. A Kaplan-Meier estimate with a log-rank test was used for recurrence-free survival (RFS) analysis. Results: The analysis included 178 patients from five institutions. The 5-year RFS rate in patients with RS 18-30 was higher in the 95GC-L group (n = 129, 96.3%) than in the 95GC-H group (n = 49, 90.9%; p = 0.002), which was consistent with results in an independent Japanese population (n = 224; p < 0.001). RFS rates significantly differed between the groups among patients with RS 11-25 as well (95GC-L, 97.4%; 95GC-H, 87.1%; p = 0.001). RFS rates did not differ between patients with RS 18-25 (94.8%) and those with RS 26-30 (93.8%; p = 0.33). Conclusions: 95GC can predict recurrence risk in patients with ER-positive, HER2-negative, node-negative invasive breast cancer and intermediate RS. Further prospective retrospective studies in the TAILORx population are warranted to confirm that 95GC can identify patients who may benefit from adjuvant chemoendocrine therapy.

Beyond TILs: Predictors of pathologic complete response (pCR) in triple-negative breast cancer (TNBC) patients with moderate tumor-infiltrating lymphocytes (TIL) receiving neoadjuvant therapy

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Background: Increased TIL in TNBC is associated with higher rates of pCR. High TIL is also associated with improved disease free survival and overall survival. The aim of this study is to identify data cut-points of pre-treatment low, moderate and high TIL count based on pCR and to identify clinical and pathological predictors of pCR in patients with moderate TIL. Methods: We evaluated the relationship between pCR and TIL in 180 patients with stage I-III TNBC enrolled in the ARTEMIS trial (NCT02276443). Recursive portioning was used to identify cut-points. Clinical and pathological variables such as age at diagnosis, stage, race, histology as well as Ki-67, vimentin, and androgen receptor (AR) by immunohistochemistry, were evaluated in pts with moderate TIL. A multivariable logistic regression model identified variables independently, significantly associated with pCR. Results: Four TIL groups were identified with pCR rates of 23%, 31%, 48% and 78% respectively (p < 0.0001) (Table A). In the two combined moderate TIL groups, 90 (97%) pts were evaluable for the multivariate model. Stage I-II disease, high Ki-67 and low AR were associated with increased probability of pCR (Table B). The multivariable logistic regression model area under the ROC curve was 0.78 (95% CI=0.68-0.88; p<0.0001). A model of computed risk score [ Stage I-II (score 2)+Ki-67≥ 50% (score 1)+AR<10% (score 1)] predicted a probability of 67% for pCR when all three variables were favorable (Table). Conclusions: Four TIL groups were identified. In pts with moderate TIL levels, early stage disease, high Ki-67 and low AR were associated with increased probability of pCR with neoadjuvant therapy. [Table: see text]

HER2 targeted therapy and outcome in HER2-equivocal cases after 2018 ASCO/CAP HER2 guideline modification

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Background: The best targeted therapeutic approach for HER2-equivocal cases remains unclear. New ASCO/CAP HER2 guidelines are intended to decrease this ambiguity by combining immunohistochemistry and in situ hybridization to resolve equivocal cases as positive or negative. However, the benefit of anti-HER2 therapy in HER2-equivocal cases is unknown. Methods: We retrospectively reviewed patients who visited MD Anderson from April 2017 to March 2018 with equivocal HER2 results based on the 2013 ASCO/CAP guidelines. The population was divided into 2 cohorts according to biopsy origin (primary cohort: biopsy from breast or axilla; recurrent/metastatic cohort: biopsy from recurrent or metastatic site). HER2 status was redefined using the 2018 ASCO/CAP guidelines. OS and PFS were calculated (Kaplan-Meier method) based on redefined HER2 status and use of HER2 targeted therapy. Results: A total of 139 equivocal results were found. Primary cohort had 90 patients (33 received neoadjuvant and 57 adjuvant therapy). HER2 IHC results were 0 (6.6%), 1+ (37.7%), 2+ (50%), 3+ (1.1%), and no IHC (4.4%). 94% of HER2-equivocal results became HER2 negative. Only 5 patients received anti-HER2 therapy, all of them in the HER2-negative group. After median follow-up of 1.91 yrs, 3 deaths and 8 progressions had occurred. There was no statistically significant association between anti-HER2 therapy and OS (p = 0.67) or PFS (p = 0.49). The recurrence/metastatic cohort had 49 cases with equivocal results. HER2 IHC results were 0 (6.1%), 1+ (22.4%), 2+ (26.5%), and no IHC (44.9%). 55% of HER2-equivocal results became HER2 negative, and only 1 patient received anti-HER2 therapy. After median follow-up of 2.96 yrs, 15 deaths and 35 progressions had occurred. There was no statistically significant association between anti-HER2 therapy and OS (p = 0.61) or PFS (p = 0.78). Conclusions: Most HER2-equivocal results were redefined as HER2 negative using the new ASCO/CAP guidelines. Association between anti-HER2 therapy and OS or PFS according to the new HER2 status was not observed. Although this is a small sample with short follow-up, patients with HER2-equivocal breast cancers seem to have clinical behavior similar to HER2-negative breast cancer.

Atypical plant homeodomain of UBR7 functions as an H2BK120Ub ligase and breast tumor suppressor

The roles of Plant Homeodomain (PHD) fingers in catalysis of histone modifications are unknown. We demonstrated that the PHD finger of Ubiquitin Protein Ligase E3 Component N-Recognin7 (UBR7) harbors E3 ubiquitin ligase activity toward monoubiquitination of histone H2B at lysine120 (H2BK120Ub). Purified PHD finger or full-length UBR7 monoubiquitinated H2BK120 in vitro, and loss of UBR7 drastically reduced H2BK120Ub genome-wide binding sites in MCF10A cells. Low UBR7 expression was correlated with occurrence of triple-negative breast cancer and metastatic tumors. Consistently, UBR7 knockdown enhanced the invasiveness, induced epithelial-to-mesenchymal transition and promoted metastasis. Conversely, ectopic expression of UBR7 restored these cellular phenotypes and reduced tumor growth. Mechanistically, UBR7 loss reduced H2BK120Ub levels on cell adhesion genes, including CDH4, and upregulated the Wnt/β-Catenin signaling pathway. CDH4 overexpression could partially revert UBR7-dependent cellular phenotypes. Collectively, our results established UBR7 as a histone H2B monoubiquitin ligase that suppresses tumorigenesis and metastasis of triple-negative breast cancer.

Abstract P1-05-05: eEF1A2 facilitates PTEN-GSK3β mediated Aurora-A protein degradation during S-G2 phase inactivated in PTEN-deficient breast cancer

The AURKA gene, encoding Aurora kinase-A (Aurora-A), is frequently amplified and overexpressed across multiple cancer types correlating with poor prognosis. Although the AURKA gene is frequently amplified in human cancers, underlying mechanism(s) for Aurora-A protein stability through different phases of cell cycle are not well elucidated. Inhibiting the kinase activity and promoting protein degradation are two well-validated conceptual strategies for targeting protein kinases in cancers. Here, we demonstrate that Eukaryotic Elongation Factor 1 Alpha 2 (eEF1A2) facilitates PTEN-GSK3β mediated Aurora-A protein degradation through the SCF complex (SKP1-Cul1-FBXW7) during the S/G2 phase of proliferating cells. In contrast, this mechanism is inactivated in cancer cells accompanying PTEN-GSK3β pathway deficiency. Mechanistically, eEF1A2 interacts with Aurora-A, GSK3β, FBXW7 and Cul1-E3 ligase, as the SCF complex, to facilitate Aurora-A polyubiquitination for 26S proteasomal degradation. eEF1A2 promotes PTEN phosphorylation at T366 and stability, inactivates AKT and activates GSK3β which in turn phosphorylates Aurora-A at S283, S284 and S342. The phosphorylation of Aurora-A at S342 is detected during S/G2 phase of cell mitosis in parallel with eEF1A2-SCF complex formation with active form of GSK3β and neddylated Cul1. Conversely, genetic ablation of EEF1A2 and PTEN, activation of AKT, inhibition of GSK3β, expression of Aurora-A phosphodeficient-mutant attenuates the Aurora-A protein degradation which is corroborated in Aurora-A overexpressing mouse mammary carcinomas and human breast carcinomas. This study identifies a novel mechanism of Aurora-A protein degradation mediated eEF1A2-PTEN-GSK3β pathway and provides a framework for the discovery of Aurora-A therapeutic targets in breast cancer that harbors deficiency of PTEN tumor suppressor pathway.

Citation Format: Treekitkarnmongkol W, Solis LM, Kai K, Thompson AM, Tian W, Wistuba II, Sasai K, Jltsumori Y, Sahin AA, Hawke DH, Lee JM, Qin L, Bawa-Khalfe T, Rad R, Wong KK, Abbott CM, Katayama H, Sen S. eEF1A2 facilitates PTEN-GSK3β mediated Aurora-A protein degradation during S-G2 phase inactivated in PTEN-deficient breast cancer [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 P1-05-05.

Abstract P6-17-38: Clinical and pathological features of breast cancer with 'polysomy' of Chromosome 17

Background: Anti-HER2 therapy is a standard of care for patients with HER2+ breast cancer. HER2 status is routinely evaluated using immunohistochemical stain and/or florescence in situ hybridization (FISH). Interpretation of FISH results may be challenging in tumors with 'polysomy' of chromosome 17 ('polysomy'17), which is defined by increased chromosome enumeration probe 17 (CEP17) signal number. There is evident that 'polysomy'17 might account for anti-HER2 therapy response in breast cancer (BC) with normal HER2/CEP17 ratio. This study aims to study the clinical and pathological features of BC with 'polysomy'17. Method: Primary BC were selected based on elevated CEP17 count (≥3.0) in HER2 FISH performed at MD Anderson Cancer Center between April 2014 and March 2018 (n=385). Patient charts were reviewed for detailed clinical and pathological features. These cases were further divided into four groups according to HER2/CEP17 and HER2 copy number, based on ASCO-CAP guidelines: group 1 (HER2+) – HER2/CEP17≥2.0, HER2 copies≥4.0; group 3 (HER2+) – ratio&lt;2.0, HER2 copies≥ 6.0; group 4 (HER2 equivocal) – ratio &lt;2.0, HER2 copies ≥4.0 and &lt;6.0; group 5 (HER2-) – ratio&lt;2.0, HER2 copies&lt;4.0. Chi-square tests were performed to study the difference of these characters. Results: In comparison with groups 1 and 3, BC in groups 4 and 5 are more commonly seen in elder patients (p=0.001). Also, these tumors show higher pathological category (p&lt;0.001) and higher rate of lymph nodes metastasis (p&lt;0.05). The clinical and pathological features are summarized in [Table 1]. Conclusion: Understanding the clinical and pathological features of BC with 'polysomy'17 may help clinically to choose patients who might be benefit from anti-HER2 therapy. Further study is to follow up the therapy response of those who received anti-HER2 treatment in this cohort of patients.

Clinical and pathological characteristics of breast cancer with 'polysomy' of chromosome 17  Total (N=385)Group 1 ( N=131)Group 3 (N=25)Group 4 (N=69)Group 5 (N=160)P valueAge (year)Mean (range)56.8 (25-94)53.9 (25-83)52.8 (26-75)58 (33-92)59.3 (29-94)0.001Race RaceBlack (%)37 (9.6)14 (10.7)4 (16)5 (7.2)14 (8.8)0.873 Hispanic (%)61 (15.8)23 (17.6)3 (12)12 (17.4)23 (14.4)  White (%)251 (65.2)82 (62.6)14 (56)44 (63.8)111 (69.4)  Other (%)36 (9.4)12 (9.1)4 (16)8 (11.6)12 (7.4) GenderFemale (%)383 (99.5)131 (100)25 (100)68 (98.6)159 (99.4)0.478 Male (%)2 (0.5)0 (0)0 (0)1 (1.4)1 (0.6) Histology typeIDC, NOS (%)350 (90.9)121 (92.4)20 (80)66 (95.7)143 (89.4)0.471 ILC (%)9 (2.3)3 (2.3)1 (4)0 (0)5 (3.1)  Others (%)26 (6.8)7 (5.3)4 (16)3 (4.3)12 (7.5) Nuclear gradeI (%)4 (1.2)2 (1.8)0 (0)1 (1.8)1 (0.7)0.044 II (%)122 (37)30 (26.3)12 (50)19 (33.3)61 (45.5)  III (%)203 (61.8)82 (71.9)12 (50)37 (64.9)72 (53.8)  NA561711226 Pathological tumor categorypT0+Tis (%)61 (21)36 (36.3)3 (20)5 (10.9)17 (13.1)&lt;0.001 pT1 (%)125 (43.2)39 (39.4)7 (46.7)20 (43.5)59 (45.4)  pT2+T3+T4 (%)104 (35.8)24 (24.3)5 (33.3)21 (45.6)54 (41.5)  NA9532102330 Pathological lymph node categorypN0 (%)187 (65.4)81 (82.7)11 (73.3)22 (47.8)73 (57.5)0.048 pN1+N2+N3 (%)99 (34.6)17 (17.3)4 (26.7)24 (52.2)54 (42.5)  pNx (%)9933102333 

Citation Format: Sun H, Chen H, Lim B, Sahin AA. Clinical and pathological features of breast cancer with 'polysomy' of Chromosome 17 [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 P6-17-38.

Abstract P3-10-23: Changes in the expression of HER2 and other genes in HER2-positive metastatic breast cancer induced by treatment with ado-trastuzumab emtansine and/or pertuzumab/trastuzumab

Background: Although tremendous progress has been achieved with targeted therapy for HER2-positive (HER2+) metastatic breast cancer, most advanced tumors eventually develop resistance. Improving our understanding of mechanisms of resistance to anti-HER2 therapy is needed to develop new therapeutic approaches. The purpose of this study was to identify the mechanisms of resistance to treatment with ado-trastuzumab emtansine (T-DM1) and/or taxane/pertuzumab/trastuzumab (TPH).

Methods: In our preclinical analysis, HER2+ cell lines resistant to treatment with T-DM1 (n=5), and pertuzumab/trastuzumab (n=3) were generated. HER2 expression in the original and resistant cell lines was compared using Western blot, and HER2 gene amplification was compared in them using fluorescence in situ hybridization (FISH) and a Droplet Digital Polymerase Chain Reaction HER2 copy-number-validation assay. In our clinical analysis, nine patients with HER2+ metastatic breast cancer who had progressed on T-DM1 and/or TPH were enrolled. Patients underwent biopsies following treatment with T-DM1 and/or TPH. Targeted next-generation sequencing was performed using the FoundationOne® assay (Foundation Medicine, Inc.) to identify gene alterations. Also, the HER2 expression before and after the therapy was compared using immunohistochemistry and/or FISH.

Results: In preclinical analysis, HER2 expression/amplification by Western blot and gene copy-number analysis was significantly decreased in T-DM1–resistant cell lines (four of five cell lines; P &lt; 0.01) but not in pertuzumab/trastuzumab-resistant cell lines (none of three cell lines). In clinical analysis, the patients' median age was 54 years (range, 45-77 years), and five patients (56%) were ER+. Five patients (56%) received first-line anti-HER2 therapy, and four patients (44%) received two lines of anti-HER2 therapy prior to enrollment. We observed loss of HER2 expression in four of nine patients (44%) after undergoing anti-HER2 therapy. After receiving TPH, one of eight patients (13%) lost HER2 positivity according to FISH. In contrast, after T-DM1, three of four tested patients (75%) lost HER2 amplification by FISH. As for next-generation sequencing, we analyzed seven samples: three after treatment with TPH and four after treatment with T-DM1. In four of these samples (57%), we observed loss of HER2 amplification: one after treatment with TPH and three after treatment with T-DM1. TP53 mutations were seen in all patients. Additionally, we observed TOP2A and MCL1 amplification in two patients with ERBB2 amplificationand AKT1 amplification in one patient with ERBB2 amplification loss.

Conclusions: We show for the first time that T-DM1–resistant breast cancer cells lose HER2 expression and amplification. Additionally, we observed loss of HER2 expression in patient samples following treatment with HER2 targeted therapy. Further study of resistant tumor samples is required to understand the impact of HER2 loss on outcomes. For the time being, repeating biopsy analysis of a metastatic site after treatment with T-DM1 to determine the HER2 expression status is reasonable, and it may increase the efficacy of future anti-HER2 therapy.

Citation Format: Kida K, Lee J, Liu H, Lim B, Murthy RK, Sahin AA, Tripathy D, Ueno NT. Changes in the expression of HER2 and other genes in HER2-positive metastatic breast cancer induced by treatment with ado-trastuzumab emtansine and/or pertuzumab/trastuzumab [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 P3-10-23.

Multidisciplinary Intraoperative Assessment of Breast Specimens Reduces Number of Positive Margins

BACKGROUND

Successful breast-conserving surgery requires achieving negative margins. At our institution, the whole surgical specimen is imaged and then serially sectioned with repeat imaging. A multidisciplinary discussion then determines need for excision of additional margins. The goal of this study was to determine the benefit of each component of this approach in reducing the number of positive margin.

METHODS

This single-institution, prospective study included ten breast surgical oncologists who were surveyed to ascertain whether they would have taken additional margins based their review of whole specimen images (WSI) and review of serially sectioned images (SSI). These results were compared with the multidisciplinary decisions (MDD) and pathology results. Margin status was defined using consensus guidelines.

RESULTS

One hundred surveys were completed. Margins on the original specimen were positive or close in 21%. After WSI, surgeons reported that they would have taken additional margins in 26 cases, reducing the number of positive/close margins from 21 to 13% (p < 0.001). After SSI, 52 would have taken additional margins; however, the number of positive/close margins remained 13%. MDD resulted in additional margins taken in 56 cases, reducing the number of positive/close margins to 7% (p < 0.001 compared with SSI).

CONCLUSIONS

While surgeon review of specimen radiographs can decrease the number of positive or close margins from 21 to 13%, more rigorous multidisciplinary, intraoperative margin assessment reduces the number of close or positive margins to 7%.

Long-Term Impact of Regional Nodal Irradiation in Patients With Node-Positive Breast Cancer Treated With Neoadjuvant Systemic Therapy

PURPOSE

The impact of regional nodal irradiation (RNI) on locoregional recurrence (LRR) and any disease recurrence (DR) in women with node-positive breast cancer who receive neoadjuvant systemic therapy (NAT) is unknown.

METHODS AND MATERIALS

The impact of RNI on LRR and DR was estimated with the cumulative incidence method in 1289 women with stage II to III breast cancer with cytologically confirmed axillary metastases who received NAT between 1989 and 2007. Multicovariate Cox regression analysis was performed to examine the effect of RNI after accounting for other predictive and prognostic variables.

RESULTS

The median follow-up after definitive surgery was 10.2 years. Axillary pathologic complete response (pCR) was observed in 368 of 1289 patients (28.5%). On univariate analysis, axillary pCR reduced 10-year LRR risk from 9.7% to 4.8% (P = .006) and DR risk from 43.0% to 17.0% (P < .001). RNI was administered to 1080 of 1289 patients (83.8%). On univariate analysis, RNI did not affect 10-year LRR risk (no RNI, 9.4%; RNI, 8.1%; P = .62) or DR risk (no RNI, 31.3%; RNI, 36.5%; P = .16). On multicovariate analysis, RNI significantly reduced the risk of LRR (hazard ratio, 0.497; 95% confidence interval [CI], 0.279-0.884; P = .02) and DR (hazard ratio, 0.731; 95% CI, 0.541-0.988; P = .04) and showed a particularly strong reduction in risk of DR in patients with HER2+ disease who received trastuzumab (hazard ratio, 0.237; 95% CI, 0.109-0.517; P = .0003). A nomogram to predict 10-year LRR risk with and without RNI has been generated to assist clinicians in individualizing treatment decisions based on patient and disease characteristics and response to NAT.

CONCLUSIONS

Adjuvant RNI reduces risk of LRR and DR in patients with breast cancer with axillary metastases who receive NAT across subtypes and particularly decreases the risk of DR in HER2+ breast cancer treated with trastuzumab. Enrollment on the National Surgical Adjuvant Breast and Bowel Project B-51/Radiation Therapy Oncology Group 1304 protocol is encouraged to help determine whether RNI can be omitted in patients with axillary pCR to NAT.

Revisiting the definition of estrogen receptor positivity in HER2-negative primary breast cancer

Background

Although 1% has been used as cut-off for estrogen receptor (ER) positivity, several studies have reported that tumors with ER < 1% have characteristics similar to those with 1% ≤ ER < 10%. We hypothesized that in patients with human epidermal growth factor 2 (HER2)-negative breast cancer, a cut-off of 10% is more useful than one of 1% in discriminating for both a better pathological complete response (pCR) rate to neoadjuvant chemotherapy and a better long-term outcome with adjuvant hormonal therapy. Our objectives were to identify a percentage of ER expression below which pCR was likely and to determine whether this cut-off value can identify patients who would benefit from adjuvant hormonal therapy.

Patients and methods

Patients with stage II or III HER2-negative primary breast cancer who received neoadjuvant chemotherapy followed by definitive surgery between June 1982 and June 2013 were included. Logistic regression models were used to assess the association between each variable and pCR. Cox models were used to analyze time to recurrence and overall survival. The recursive partitioning and regression trees method was used to calculate the cut-off value of ER expression.

Results

A total of 3055 patients were analyzed. Low percentage of ER was significantly associated with high pCR rate (OR = 0.99, 95% CI = 0.986-0.994, P < 0.001). The recommended cut-off of ER expression below which pCR was likely was 9.5%. Among patients with ER ≥ 10% tumors, but not those with 1%≤ER < 10% tumors, adjuvant hormonal therapy was significantly associated with long time to recurrence (HR = 0.24, 95% CI = 0.16-0.36, P < 0.001) and overall survival (HR = 0.32, 95% CI = 0.2-0.5, P < 0.001).

Conclusion

Stage II or III HER2-negative primary breast cancer with ER < 10% behaves clinically like triple-negative breast cancer in terms of pCR and survival outcomes and patients with such tumors may have a limited benefit from adjuvant hormonal therapy. It may be more clinically relevant to define triple-negative breast cancer as HER2-negative breast cancer with <10%, rather than <1%, of ER and/or progesterone receptor expression.