ESMO expert consensus statements (ECS) on the definition, diagnosis, and management of HER2-low breast cancer

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged as a targetable subset of breast tumors, based on the evidence from clinical trials of novel anti-HER2 antibody-drug conjugates. This evolution has raised several biological and clinical questions, warranting the establishment of consensus to optimally treat patients with HER2-low breast tumors. Between 2022 and 2023, the European Society for Medical Oncology (ESMO) held a virtual consensus-building process focused on HER2-low breast cancer. The consensus included a multidisciplinary panel of 32 leading experts in the management of breast cancer from nine different countries. The aim of the consensus was to develop statements on topics that are not covered in detail in the current ESMO Clinical Practice Guideline. The main topics identified for discussion were (i) biology of HER2-low breast cancer; (ii) pathologic diagnosis of HER2-low breast cancer; (iii) clinical management of HER2-low metastatic breast cancer; and (iv) clinical trial design for HER2-low breast cancer. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. A review of the relevant scientific literature was conducted in advance. Consensus statements were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This article presents the developed statements, including findings from the expert panel discussions, expert opinion, and a summary of evidence supporting each statement.

Single and combined impacts of irradiation and surgery on lymphatic vasculature and fibrosis associated to secondary lymphedema

Lymphedema (LD) refers to a condition of lymphatic dysfunction associated with excessive fluid accumulation, fibroadipose tissue deposition and swelling. In industrialized countries, LD development mainly results from a local disruption of the lymphatic network by an infection or cancer-related surgery (secondary LD). In the absence of efficient therapy, animal models are needed to decipher the cellular and molecular mechanisms underlying LD and test putative drugs. In this study, we optimized and characterized a murine model of LD that combines an irradiation of the mice hind limb and a radical surgery (lymph node resection associated to lymphatic vessel ligation). We investigated the respective roles of irradiation and surgery in LD formation by comparing their impacts, alone or in combination (with different intervention sequences), on eight different features of the pathology: swelling (paw thickness), indocyanine green (ICG) clearance, lymphatic vasculature remodeling, epidermal and dermal thickening, adipocyte accumulation, inflammatory cell infiltration and collagen deposition. This study supports the importance of radiation prior to surgery to experimentally induce a rapid, severe and sustained tissue remodeling harboring the different hallmarks of LD. We provide the first experimental evidence for an excessive deposition of periostin (POSTN) and tenascin-C (TNC) in LD. Through a computerized method of digital image quantification, we established the spatial map of lymphatic expansion, as well as collagen, POSTN and TNC deposition in papillary and reticular dermis of lymphedematous skins. This mouse model is available to study the patho-physiology of LD and test potential therapeutic targets.

Abstract PD8-02: Residual axillary involvement in early breast cancer in patients with positive sentinel nodes after neoadjuvant chemotherapy (NACT)

Background:The association between pathological complete remission (pCR) in the breast and clinical/pathological parameters is well established, whereas the role of these parameters in the prediction of residual axillary involvement after NACT is unclear. The goal is to identify a subset of patients who do not need axillary treatment. We used data from Arm B of the SENTINA trial to analyze this association.

Methods:Patients from arm B of the SENTINA trial with clinically and sonographically unsuspicious axillary nodes but with histologically proven involvement of SLNs prior to NACT were analyzed. All patients had SLNB and axillary dissection after NACT. Univariate analyses were performed to evaluate the association between clinical/pathological parameters and axillary involvement after NACT.

Results:Arm B of the SENTINA study contained 360 patients, 318 of which were evaluable with respect to the above parameters. After NACT 71/318 (22.3%) patients had involved SLNs or non-SLNs; 71/318 (22.3%) had a pCR in the breast. We observed a significant association between pCR in the breast and negative ER status, negative PR status, positive HER2 status, triple negative (TN) status, tumor size before and after NACT, multifocality, lobular morphology and axillary involvement after NACT. Regarding residual axillary burden only the associations with lobular morphology, extracapsular invasion, multifocality, positive HER2 status and pCR in the breast were statistically significant.

Conclusion:Our analysis demonstrates that patients enrolled in the SENTINA trial with clinically and sonographically unsuspicious axillary nodes but proven histological involvement of SLNs prior to NACT have positive axillary nodes in 22.3 % after NACT. This rate is confirming similar results from other groups. Although we found statistically significant associations between pCR in the breast and clinical/pathological parameters, only the association between lobular type, extracapsular invasion, positive HER2 status and pCR in the breast and residual axillary involvement after NACT were statistically significant. We cannot clearly identify a subset of patients for whom axillary treatment after NACT could be safely omitted if SLNs were positive. Our data are well in line with recently presented data demonstrating that the association between pCR in the breast and free axillary nodes after NACT is particularly strong in patients with TN and HER2 positive tumors. This question will be addressed in future trials currently under development.

Citation Format: Kolberg H-C, Liedtke C, Bauerfeind I, Fehm T, Fleige B, Hauschild M, Helms G, Lebeau A, Schmatloch S, Schrenk P, Schwentner L, Stäbler A, Loibl S, Untch M, Kühn T. Residual axillary involvement in early breast cancer in patients with positive sentinel nodes after neoadjuvant chemotherapy (NACT) [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 PD8-02.

Abstract P4-02-08: Statistical modeling of influential variables affecting HER2-positivity in breast cancer: Final analyses from two large, multicenter, noninterventional studies in Germany

Background:

While HER2 testing in breast cancer (BC) has been routine for over a decade, testing quality remains a challenge. Currently, HER2-positivity rate is the only recommended quality indicator. However, the large, observational, prospective NIU HER2 study in Germany quantified the impact of patient- and tumor-related characteristics such as histologic grade, hormone receptor (HR) status, histologic subtype, age, and nodal status on HER2-positivity, indicating that these factors need to be considered when evaluating HER2-positivity as a measure of testing quality (Rüschoff et al. Mod Pathol 2017). We now report the final analyses from the multicenter EPI HER2 BC study (ML29763, NCT02666261) in Germany where we compared NIU and EPI study data, and aimed to validate the NIU study model.

Methods:

Data from eligible patients with invasive BC were collected (HER2 test result; patient- and tumor-related factors) and variables influencing HER2-positivity identified and compared between studies. The NIU study model was validated and its predictive power determined using newly collected data from the EPI study, with cutoff and variable coefficients from the previous NIU analysis. Additional promising variables were explored, and their relative influence investigated, using multiple stepwise logistic regression.

Results:

In total, 14,729 (EPI) and 15,281 (NIU) BC samples were analyzed. Distributions of the main variables were comparable; overall HER2-positivity rates were 13.47% (EPI) and 14.24% (NIU). Fitting the NIU study model to EPI study data demonstrated that all five covariates from the NIU study analyses significantly affected HER2-positivity (p < 0.01); the influence for each covariate differed only slightly between studies (in EPI, histologic grade had most influence followed by histologic subtype, HR status, nodal status, and age). Prediction profiles were used to visualize the relationship between the model-predicted probability of HER2-positivity and the five identified covariates, which showed good comparability between studies. The receiver operating characteristics area under the curve (ROC AUC) of the NIU model used to predict HER2-positivity in the EPI study data was close to that of the model fitted to the NIU data, thus successfully validating the NIU model. To further improve the model, the categorical HR status was replaced by estrogen receptor (ER) and progesterone receptor (PgR) expression. Inclusion of ER and PgR as continuous variables improved the predictive strength of the model (ROC AUC = 0.74; sensitivity = 0.76; specificity = 0.63). Based on this improved model, PgR status had the highest influence on HER2-positivity, followed by histologic grade, histologic subtype, nodal status, ER status, and age.

Conclusions:

Results from our analyses confirm the statistically and clinically significant influence of patient- and tumor-related factors on HER2-positivity, and highlight the necessity to integrate these factors into the quality control assessment of HER2 testing. Implementation of this model in routine practice may assist in addressing issues with interlaboratory variation, and help to identify centers with HER2 testing problems more accurately.

Citation Format: Rüschoff J, Lebeau A, Kreipe H, Sinn P, Schildhaus H-U, Decker T, Ammann J, Künzel C, Koch W, Untch M. Statistical modeling of influential variables affecting HER2-positivity in breast cancer: Final analyses from two large, multicenter, noninterventional studies in Germany [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 P4-02-08.

Abstract PD8-03: Conversion rates from positive to negative axillary involvement in breast cancer patients presenting with biopsy-proven axillary metastases prior to primary systemic therapy (PST) – A transSENTINA subproject

Background:

Modern chemotherapy carries a high potential of converting patients with clinically suspicious axillary nodes (cN+) prior to PST to clinically (ycN0) or pathologically (ypN0) negative nodes after PST. Clinical and sonographical axillary assessment, however, may be inadequate and therefore pathological assessment of suspicious axillary nodes is recommended. We analyzed the association between clinical / pathological parameters and positive to negative conversion in patients with biopsy-proven axillary metastases in Arm C of the SENTINA trial (i.e. patients with “true conversion”).

Methods:

Arm C of the SENTINA trial included patients converting from cN+ to ycN0 through PST from a prospective study. We limited our analysis to patients who had biopsy-proven axillary involvement. Univariate regression analysis was carried out to assess the association between patients with vs. without axillary disease after PST in i) patients with biopsy-proven involvement and ii) patients without biopsy proof of metastases.

Results:

Among 596 patients in arm C of the SENTINA trial with clinically and or sonographically suspicious ipsilateral axillary nodes, 439 (73,7%) 157 (26,3%) patients had a biopsy. In 152 patients (96,8%), lymph node metastases were confirmed and in 5 patients (3,2%), no malignant cells were identified. In both groups, we found a significant association (p<0,05) between increased rate of axillary conversion and small tumor diameter after PST, absence of multifocality, absence of lymphovascular invasion (LVI), ER and/or PR negativity, HER2 negativity, triple negative disease, and complete pathological response (pCR). No multiple testing corrections were performed due to an exploratory setting. However, only among patients with biopsy-proven involvement prior to PST, we found grade-3-tumors to be significantly associated with reduced probability of residual axillary involvement (76.1 vs. 33.8%, compared to G1 and G2, p=0.0323).

Conclusion:

Our analysis demonstrates that in patients with biopsy-proven axillary involvement before NST, parameters associated with axillary conversion are similar to those among patients classified as having nodal disease based on clinical and or sonographical assessment (cN+). Our analyses demonstrate that in biopsy-proven axillary metastases before NST, modern chemotherapy regimens result in significant rates of axillary conversion. This underscores the need to deescalate axillary staging / treatment with the goal to further avoid unnecessary axillary surgery.

Citation Format: Liedtke C, Kolberg H-C, Krajewska M, Bauerfeind I, Fehm T, Fleige B, Helms G, Lebeau A, Staebler A, Loibl S, Untch M, Kühn T. Conversion rates from positive to negative axillary involvement in breast cancer patients presenting with biopsy-proven axillary metastases prior to primary systemic therapy (PST) – A transSENTINA subproject [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 PD8-03.

Systematic analysis of parameters predicting pathological axillary status (ypN0 vs. ypN+) in patients with breast cancer converting from cN+ to ycN0 through primary systemic therapy (PST)

Optimization of axillary staging among patients converting from clinically node-positive disease to clinically node-negative disease through primary systemic therapy is needed. We aimed at developing a nomogram predicting the probability of positive axillary status after chemotherapy based on clinical/pathological parameters. Patients from study arm C of the SENTINA trial were included. Univariable/multivariable analyses were performed for 13 clinical/pathological parameters to predict a positive pathological axillary status after chemotherapy using logistic regression models. Odds ratios and 95%-confidence-intervals were reported. Model performance was assessed by leave-one-out cross-validation. Calculations were performed using the SAS Software (Version 9.4, SAS Institute Inc., Cary, NC, USA). 369 of 553 patients in Arm C were included in multivariable analysis. Stepwise backward variable selection based on a multivariable analysis resulted in a model including estrogen receptor (ER) status (odds ratio (OR) 3.916, 95% confidence interval (CI) 2.318-6.615, p < 0.001), multifocality (OR 2.106, 95% CI 1.203-3.689, p = 0.0092), lymphovascular invasion (OR 9.196, 95% CI 4.734-17.864, p < 0.001), and sonographic tumor diameter after PST (OR 1.034, 95% CI 1.010-1.059, p = 0.0051). When validated, our model demonstrated an accuracy of 70.2% using 0.5 as cut-point. An area under the curve of 0.81 was calculated. The use of individual parameters as predictors of lymph node status after chemotherapy resulted in an inferior accuracy. Our model was able to predict the probability of a positive axillary nodal status with a high accuracy. The use of individual parameters showed reduced predictive performance. Overall, tumor biology was the strongest parameter in our models.

Abstract P6-03-01: Variables influencing HER2-positivity in breast cancer: Assessment and validation of a statistical model based on two multicenter noninterventional studies in Germany

Background:

HER2 testing in breast cancer (BC), routine for &gt;10 years, allows selection of patients (pts) for HER2-targeted therapy; however, testing quality remains a concern. While guidelines recommend assessment of HER2-positivity rates as a quality indicator, the influence of patient- or tumor-related factors on variability was unknown until we identified the effect (in order of influence) of histologic grade, hormone receptor (HR) status, histologic subtype, age, and nodal status in a large, multicenter, observational study in Germany (NIU HER2 study; Rüschoff et al., Mod Pathol 2017). Based on these variables and the statistical model developed, potential issues with HER2 testing quality in local practice may be identified. We now report interim analyses from a multicenter study in Germany (EPI HER2 BC study; NCT02666261), where data from the NIU and EPI studies were compared and the validity of the NIU study model assessed.

Methods:

Routine HER2 test results and patient- and tumor-related data were collected from eligible pts with BC. Factors influencing HER2-positivity rates in the EPI study were compared with those identified in the NIU study. The predictive power of the NIU study model, fitted to EPI data, was determined and assessments performed using the variable coefficients and cutoff resulting from the NIU study analysis. Attempts were also made to improve the model.

Results:

Analyses included 15281 (NIU) and 6019 (EPI) invasive BC samples. The distribution of relevant variables, including HER2-positivity rate (NIU: 14.4%; EPI: 13.5%), was comparable. When the NIU study model was fitted to EPI study data, all five covariates identified in the NIU analyses had a significant effect on HER2-positivity (p&lt;0.001); the order of influence for covariates differed between studies (EPI [in order of influence]: histologic grading, histologic subtype, HR status, nodal status, and age). The relationship between HER2-positivity rate and the combined influence of covariates, visualized with the NIU study prediction profiler, was reproduced with EPI study data. The NIU study statistical model, with variable coefficients and cut-point determined in the NIU study, was used to predict the HER2-positivity of samples in EPI; if their NIU model-estimated probability of positivity was &gt;0.1407, the resulting sensitivity, specificity, and receiver operating characteristic (ROC) area under the curve (AUC) were 0.7032, 0.6622, and 0.7259, respectively. Thus, initial validation of the NIU study model with EPI data was successful. Semiquantitative estrogen and progesterone receptor expression data were available from EPI only; their inclusion as independent continuous, rather than categorical, variables improved the model (ROC AUC = 0.7533).

Conclusions:

The statistical modeling approach used to analyze data from the NIU study showed that patient- or tumor-related characteristics should be considered when assessing HER2 testing quality. Our present analysis validates and improves upon this statistical model and further highlights the need to assess HER2 testing quality in BC. Comparison of calculated vs actual positivity rates may help identify centers with potential HER2 testing quality issues.

Citation Format: Rüschoff J, Lebeau A, Kreipe H, Gerharz CD, Sinn P, Schildhaus H-U, Tennstedt-Schenk C, Ammann JU, Künzel C, Koch W, Untch M. Variables influencing HER2-positivity in breast cancer: Assessment and validation of a statistical model based on two multicenter noninterventional studies in Germany [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-03-01.

Abstract P3-13-06: Development and validation of a nomogram predicting pathological axillary status (ypN0 vs. ypN+) in a subgroup of patients converting from cN+ to ycN0 through neoadjuvant therapy (NAT) – A transSENTINA substudy

Background: Particularly among patients converting from cN+ to ycN0 status through neoadjuvant therapy (NAT) the optimal method and extent of axillary staging is unclear. The aim of this analysis was to develop a nomogram predicting the probability of positive axillary status (ypN+) after PST among these patients based on clinical and pathological parameters.

Methods:Patients converting from cN+ to ycN0 due to PST included in a prospective study (SENTINA, Arm C) were included. Univariate and multivariate analyses were carried out to evaluate the association between 14 clinical/pathological parameters and pathological axillary status (ypN0 vs ypN+) using logistic regression models. Model accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed applying leave-one-out cross-validation (LOOCV) and ROC analyses. Different cut-points were evaluated. Calculations were performed using the SAS Software (Version 9.4, SAS Institute Inc., Cary, NC, USA.).

Results: Arm C contained 553 patients, 369 patients were evaluable with respect to the above parameters. Univariate analyses revealed a significant association between pathological axillary status and ER status (odds ratio (OR) 4.05, 95% confidence interval (95%CI) 2.81-5.83), PR status (OR 3.07, 95%CI 2.16-4.36), multifocality (OR 2.37, 95%CI 1.57-3.58), lymphovascular invasion (OR 8.61, 95%CI 5.12-14.46), detection of a SLN after NAT (OR .56, 95%CI .36-.87), detection method (IHC vs routine: OR .46, 95%CI .27-.78; IHC vs serial HE: OR .72, 95%CI .49-1.07; serial hematoxylin eosin (HE) vs routine: OR .639, 95%CI .39-1.04), clinical tumor size (OR 1.051, 95%CI 1.03-1.07) and pCR-status in the breast (ypT0 and ypTis vs others, OR .11, 95%CI .08-.17). A multivariate model was fitted including significant clinical parameters. Stepwise backward variable selection was carried out resulting in a model including ER status (OR 3.81, 95%CI 2.25-6.44), multifocality (OR 2.22, 95%CI 1.26-3.92), LVI (OR 9.16, 95%CI 4.68-17.90), detection of a SLN after NAT (OR .50, 95%CI .26-.95) and clinical tumor size (OR 1.03, 95%CI 1.01-1.06). In LOOCV, this model demonstrated an accuracy of 73% (sensitivity 73%, specificity 72%, PPV 75%, NPV 70%) using .5 as cut-off. Based on the performed ROC analysis an area under the curve (AUC) of 0.81 was calculated.

Conclusion: A model using ER status, multifocality, LVI, detection of a SLN after NAT and clinical tumor size was built to predict pathological axillary status (ypN+) with a high accuracy. If successfully validated based upon an independent dataset, this nomogram could allow advising patients for / against axillary surgery in case of clinical axillary conversion after NAT.

Citation Format: Liedtke C, Kolberg H-C, Kerschke L, Goerlich D, Bauerfeind I, Fehm T, Fleige B, Hauschild M, Helms G, Lebeau A, Schmatloch S, Schrenk P, Schwentner L, Staebler A, von Minckwitz G, Loibl S, Untch M, Kuehn T. Development and validation of a nomogram predicting pathological axillary status (ypN0 vs. ypN+) in a subgroup of patients converting from cN+ to ycN0 through neoadjuvant therapy (NAT) – A transSENTINA substudy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-13-06.

Partial PTEN deletion is linked to poor prognosis in breast cancer

BACKGROUND

Deletions of chromosome 10q23, including the PTEN (phosphatase and tensin homolog) locus, are known to occur in breast cancer, but systematic analyses of its clinical relevance are lacking.

METHODS

We thus analyzed a tissue microarray (TMA) with 2,197 breast cancers by fluorescence in-situ hybridization (FISH) using a PTEN-specific probe.

RESULTS

PTEN deletions were detected in 19% of no special type, 9% of lobular, 4% of tubular cancers and 46% in carcinomas with medullary features. 98.7% of deletions were heterozygous and only 1.3% were homozygous. PTEN deletion was significantly linked to advanced tumor stage (p=0.0054), high-grade (p<0.0001), high tumor cell proliferation (Ki67 Labeling Index; p<0.0001), and shortened overall survival (p=0.0090). PTEN deletions were inversely associated with features of luminal type breast cancers (ER/PR positivity; p<0.0001 each, and CCND1 amplification; p=0.0020). PTEN deletions were also strongly linked to amplification of genes involved in the PTEN/AKT pathway such as MYC (p=0.0430) and HER2 (p=0.0065). Remarkably the combined analysis of MYC, HER2, CCND1 and PTEN aberrations suggested that aberrations of multiple PTEN/AKT pathway genes have a strong additive effect on breast cancer prognosis. While cancers with one of these aberrations behaved only marginally different from cancers with none, disease outcome was markedly worse in cancers with two or more aberrations as compared to those with only one aberration (p=0.0002). In addition, the particularly poor prognosis of patients with HER2 amplification and PTEN deletions challenges the concept of PTEN deletions interfering with trastuzumab therapy.

CONCLUSION

PTEN deletion occurs in a relevant fraction of breast cancers, and is linked to aggressive tumor behavior. Reduced PTEN function cooperates with MYC and HER2 activation in conferring aggressive phenotype to cancer cells.

8p deletion is strongly linked to poor prognosis in breast cancer

Deletions of chromosome 8p occur frequently in breast cancers, but analyses of its clinical relevance have been limited to small patient cohorts and provided controversial results. A tissue microarray with 2,197 breast cancers was thus analyzed by fluorescence in-situ hybridization using an 8p21 probe in combination with a centromere 8 reference probe. 8p deletions were found in 50% of carcinomas with no special type, 67% of papillary, 28% of tubular, 37% of lobular cancers and 56% of cancers with medullary features. Deletions were always heterozygous. 8p deletion was significantly linked to advanced tumor stage (P < 0.0001), high-grade (P < 0.0001), high tumor cell proliferation (Ki67 Labeling Index; P < 0.0001), and shortened overall survival (P < 0.0001). For example, 8p deletion was seen in 32% of 290 grade 1, 43% of 438 grade 2, and 65% of 427 grade 3 cancers. In addition, 8p deletions were strongly linked to amplification of MYC (P < 0.0001), HER2 (P < 0.0001), and CCND1 (p = 0.001), but inversely associated with ER receptor expression (p = 0.0001). Remarkably, 46.5% of 8p-deleted cancers harbored amplification of at least one of the analyzed genes as compared to 27.5% amplifications in 8p-non-deleted cancers (P < 0.0001). In conclusion, 8p deletion characterizes a subset of particularly aggressive breast cancers. As 8p deletions are easy to analyze, this feature appears to be highly suited for future DNA based prognostic breast cancer panels. The strong link of 8p deletion with various gene amplifications raises the possibility of a role for regulating genomic stability.

[Invasive breast cancer: the current WHO classification]

The World Health Organization (WHO) classification of tumors of the breast defines the international standards for tumor categorization and nomenclature. The fourth edition, published in 2012, provides an update on the current knowledge concerning the classification, immunohistology profile, differential diagnosis and genetics of these lesions. Compared to the previous edition, some terms have been modified, some entities were reclassified and some current molecular data have been added. This article focuses on invasive carcinomas. Definitions for histological diagnosis are supplemented by clinical, macroscopic and molecular characteristics as well as prognostic and predictive features.

Multigene Assays for Classification, Prognosis, and Prediction in Breast Cancer: a Critical Review on the Background and Clinical Utility

Gene signatures which are based on multigene profiling assays have been developed for the purpose to better define the prognosis and prediction of therapy results in early-stage breast cancer. These assays were designed to be more specific than conventional clinico-pathologic parameters in the selection of patients for (neo-)adjuvant treatment and in effect help to avoid unnecessary cytotoxic treatment. In this review we describe molecular risk scores, for which tests are commercially available (PAM50®, MammaTyper®, MammaPrint®, Oncotype DX®, Endopredict®, Genomic Grade Index®) and IHC risk scores (Mammostrat® and IHC4), and discuss the current evidence of their clinical use.

Prognostic relevance of AIB1 (NCoA3) amplification and overexpression in breast cancer

AIB1 (amplified in breast cancer 1) is an estrogen receptorα (ERα) co-activator, known to be amplified and overexpressed in a fraction of breast cancers. It has been linked to prognosis and tamoxifen resistance. However, results have been ambiguous. The different functions of AIB1 in ERα-positive and -negative disease are poorly understood. Therefore, we analyzed the clinical significance of AIB1 in breast cancer with respect to ERα-status and characterized the subgroups. 2,197 breast carcinomas sampled on a pre-existing tissue microarray (TMA) were analyzed for AIB1 expression and amplification by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).

RESULTS

AIB1 expression was detected in 60 % of the tumors. It was associated with tumor size (p = 0.003), high histological grade (p < 0.0001), poor disease-specific, and overall survival (p = 0.0018 and p = 0.003). There was a strong inverse relationship between AIB1 and ERα expression (p < 0.0001). AIB1 overexpression was associated with increased Ki67 labeling index (p < 0.0001), even if analyzed for different ER expression levels. AIB1 amplification was found in 11 % of the carcinomas. It was associated with high histological grade (p = 0.0012), lymph node involvement (p = 0.0163), and poor disease-specific survival (p = 0.0032) but not with overall survival (p = 0.1672) or ER status (p = 0.4456). If ER-positive tumors were stratified according to their AIB1 amplification status, there was a significant worse disease-specific survival in cases showing AIB1 amplification (p = 0.0017). AIB1 expression is associated with unfavorable prognosis and tumor phenotype. It seems to unfold its oncogenic potential at least in part independent from its role as an ERα co-activator. AIB1 has an impact on cell cycle regulation in ERα-positive as well as ERα-negative tumors. Furthermore, AIB1 amplification characterizes a subgroup of ERα-positive breast cancer with worse outcome. Therefore, AIB1 might be helpful to identify those ERα-positive breast cancers patients who are candidates for adjuvant chemotherapy.

Genetic mapping of a major dominant gene for resistance to Ralstonia solanacearum in eggplant

Resistance of eggplant against Ralstonia solanacearum phylotype I strains was assessed in a F(6) population of recombinant inbred lines (RILs) derived from a intra-specific cross between S. melongena MM738 (susceptible) and AG91-25 (resistant). Resistance traits were determined as disease score, percentage of wilted plants, and stem-based bacterial colonization index, as assessed in greenhouse experiments conducted in Réunion Island, France. The AG91-25 resistance was highly efficient toward strains CMR134, PSS366 and GMI1000, but only partial toward the highly virulent strain PSS4. The partial resistance found against PSS4 was overcome under high inoculation pressure, with heritability estimates from 0.28 to 0.53, depending on the traits and season. A genetic map was built with 119 AFLP, SSR and SRAP markers positioned on 18 linkage groups (LG), for a total length of 884 cM, and used for quantitative trait loci (QTL) analysis. A major dominant gene, named ERs1, controlled the resistance to strains CMR134, PSS366, and GMI1000. Against strain PSS4, this gene was not detected, but a significant QTL involved in delay of disease progress was detected on another LG. The possible use of the major resistance gene ERs1 in marker-assisted selection and the prospects offered for academic studies of a possible gene for gene system controlling resistance to bacterial wilt in solanaceous plants are discussed.

So near and yet so far: the specific case of Ralstonia Solanacearum populations from Côte d'Ivoire in Africa

The genetic and phenotypic diversity of Côte d'Ivoire Ralstonia solanacearum strains was assessed on a 168-strain collection sampled on Solanaceae both in the southern lowlands and western highlands. Phylotypes I, II, and III were prevalent, though at unexpected frequencies. Phylotype I strains (87.5%) were genetically diverse and overrepresented in all agroecological areas, including highlands (AEZ III). Phylotype II strains (10.7%) only belonged to one tropical lowland-adapted broad host range lineage (IIA-35), whereas no highland-adapted potato brown rot (IIB-1) or Moko strains were detected. African phylotype III strains were rare (1.8%). They originated from a single Burkina Faso lineage (III-23) and were only found in lowlands. Three phylotype I strains were found harboring pRSC35, a plasmid identified in phylotype III strains in Cameroon. From pathogenicity tests performed on commercial varieties and tomato/eggplant/pepper references, the virulence diversity observed was high, with five pathoprofiles described. Eggplant accessions MM152 and EG203 and tomato HW7996 displayed the largest resistance spectrum and highest level. Two highly virulent phylotype I strains were able to bypass resistance of HW7996 and the eggplant reference AG91-25. Collectively, these points lead to the conclusion that the situation in Côte d'Ivoire is specific towards other African countries, and specifically from the Cameroon reference, and that within phylotype I can exist a high virulence diversity. This calls for similar studies in neighboring West African countries, linking R. solanacearum pathogen genetic diversity to strain virulence at the regional level, for the rationalization of regional resistance deployment strategies and future resistance durability studies.

P3-05-05: Cyclin D1 Gene Amplification Is Rarely Heterogeneous in Breast Cancer

Background: Amplification of Cyclin D1 (CCND1) occurs in about 10–20% of breast cancers and has been suggested to predict resistance to anti-hormonal therapy. As the diagnostic accuracy of predictive biomarkers can be substantially limited by regional expression differences within tumors, heterogeneity of CCND1 amplification was assessed in this study. To assess heterogeneity, a novel tissue microarray based analysis platform was developed.

Material and Methods: To comprehensively asses the three-dimensional molecular composition of breast cancers, a “heterogeneity TMA” was constructed containing 8 different tissue cylinders from as many different cancer containing tumor blocks as possible (at least 4) from 147 primary breast cancers. Additional tissue samples were taken from 1–4 corresponding nodal metastases from 35 of these patients. Dual labeling fluorescence in situ hybridization (FISH) with probes for CCND1 and centromere 11 was applied.

Results: The analysis revealed amplification in 29 of 133 (21.8%) patients with interpretable FISH data. CCND1 amplification was more frequently seen in ductal (22 of 87; 25.29%) than in lobular type (5 of 32; 15.63%) (p=0.251). CCND1 amplification was also associated with high tumor grade with amplification rates of 1 of 18 (5.56%) in grade 1, 15 of 72 (20.83%) in grade 2 and 12 of 40 (30%) in grade 3 carcinoma (p=0.075). CCND1 amplification was more frequently seen in ER positive cases (27 of 110; 24.55%) than in ER negative cases (1 of 17; 5.88%) (p=0.052). No association could be found between CCND1 amplification and tumor stage (p=0.445) and CCND1 amplification and PR status (p=0.752). Heterogeneous amplification status was detected in 9 of 29 (31.0%) amplified tumors, i.e. in 6.8% of all informative cases. Heterogeneity was successfully validated on large sections in all 4 heterogeneous cases with high level amplification. In the remaining 5 “heterogeneous cases” discordant results were due to variable interpretation of borderline amplification results with CCND1/centromer 11 ratios between 1.7 and 2.3. There were no discrepancies seen between primary tumors and matched lymph node metastases.

Discussion: The high degree of homogeneity seen for CCND1 amplification suggests that this alteration represents an early event in tumor development/progression in a subset of breast cancers. CCND1 status determined in a small biopsy will be highly representative of the entire tumor and will thus be appropriate for predicting treatment outcome.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-05-05.

Bacterial wilt resistance in tomato, pepper, and eggplant: genetic resources respond to diverse strains in the Ralstonia solanacearum species complex

Bacterial wilt, caused by strains belonging to the Ralstonia solanacearum species complex, inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against this disease. However, wilt resistance is often overcome due to the considerable variation among pathogen strains. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of tomato, eggplant and pepper (Core-TEP), most of which are commonly used as sources of resistance to R. solanacearum or for mapping quantitative trait loci. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of R. solanacearum. We observed six interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotypes resulted from the plants' ability to tolerate latent infections (i.e., bacterial colonization of vascular elements with limited or no wilting). The Core-Rs2 strains partitioned into three pathotypes on pepper accessions, five on tomato, and six on eggplant. A "pathoprofile" concept was developed to characterize the strain clusters, which displayed six virulence patterns on the whole set of Core-TEP host accessions. Neither pathotypes nor pathoprofiles were phylotype specific. Pathoprofiles with high aggressiveness were mainly found in strains from phylotypes I, IIB, and III. One pathoprofile included a strain that overcame almost all resistance sources.

Abstract P1-01-04: Axillary Intervention in Patients Undergoing Neoadjuvant Therapy (NST) — First Results from the SENTINA Study

Background: The optimal scheduling for sentinel lymph node biopsy (SLNB) among patients with breast cancer undergoing neoadjuvant systemic therapy (NST) is unclear. SENTINA-study is the first prospective multicenter trial that systematically examines the feasibilty and reliability of SLNB prior to and after (NST). Here we present results of a first exploratory analysis by examining distribution of N-stages in the different treatment arms and correlating the axillary status with the type of breast surgery (breast conserving therapy [BCT] vs mastectomy [ME]).

Methods: The SENTINA study is a four-arm multicenter (n= XXX) observation study. Patients will be stratified based on their clinical lymph node status prior to treatment. If the lymph node status is clinically negative SLNB is performed before NST. Patients with a negative SLN will undergo no further axillary surgery (Arm A), whereas patients with a positive SLN will be treated with sentinel-node-guided axillary dissection (SLNB-AD) after NST (Arm B). If the lymph node is clinically positive upon initial presentation, patients will undergo NST prior to any axillary intervention. If patients convert to a clinically negative lymph node status through NST they will undergo SLNB-AD (ARM C). Patients with persistent positive nodes or whose tumors progress under NST undergo primary axillary dissection (Arm D). Clinically node positive patients will be endcouraged to undergo FNA to confirm their lymph node status. A total of 1508 patients in the entire study will be needed to calculate the false-negative rate in this group with a one-sided 95% confidence interval not exceeding 10%.

Results: 873 patients have been accrued into SENTINA until may 31th 2010, 523 (59,9%) have completed their treatment. 180 (34,4%) women have been treated in Arm A and 117 (22,4%) in Arm B. In 170 (32,5%) patients the clinical axillary status converted from a clinical positive to a clinical negative status (Arm C). In 65 pts (12,4%) the axillary status remained positive or the tumor progressed under NCHT (Arm D). BCT rates in Arm A-D were 88.3%, 75.2%, 61.8% and 22.2% respectively.

Conclusion: First results of the SENTINA study show a strong correlation between the axillary status and the type of breast surgery in patients, who are treated with NST. Importantly, we demonstrate that the clinical assessment of the axillary status is unprecise. There is an urgent need to optimize the tailoring of axillary intervention in the setting of NST

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-04.

Gene amplification in ductal carcinoma in situ of the breast

Multiple different biologically and clinically relevant genes are often amplified in invasive breast cancer, including HER2, ESR1, CCND1, and MYC. So far, little is known about their role in tumor progression. To investigate their significance for tumor invasion, we compared pure ductal carcinoma in situ (DCIS) and DCIS associated with invasive cancer with regard to the amplification of these genes. Fluorescence in situ hybridization (FISH) was performed on a tissue microarray containing samples from 130 pure DCIS and 159 DCIS associated with invasive breast cancer. Of the latter patients, we analyzed the intraductal and invasive components separately. In addition, lymph node metastases of 23 patients with invasive carcinoma were included. Amplification rates of pure DCIS and DCIS associated with invasive cancer did not differ significantly (pure DCIS vs. DCIS associated with invasive cancer: HER2 22.7 vs. 24.2%, ESR1 19.0 vs. 24.1%, CCND1 10.0 vs. 14.8%, MYC 11.8 vs. 6.5%; P > 0.05). Furthermore, we observed a high concordance of the amplification status for all genes if in situ and invasive carcinoma of individual patients were compared. This applied also to the corresponding lymph node metastases. Our results indicate no significant differences between the gene amplification status of DCIS and invasive breast cancer concerning HER2, ESR1, CCND1, and MYC. Therefore, our data suggest an early role of all analyzed gene amplifications in breast cancer development but not in the initiation of invasive tumor growth.

[Results of reference pathology in mammography screening]

As a measure of quality assurance in mammography screening in Germany, obligatory double reading of histopathological specimens is currently a subject of debate. Concordance rates of more than 6000 cases gathered from several reference centres were evaluated. In accordance with several international studies, overall agreement in single and double readings in German mammography screening was approximately 95%. Concordance rates were even higher for malignancies (99%). Variations are more common in the case of lesions, the biological significance of which remains unclear (flat atypia, lobular neoplasm, papilloma). This is the result of a currently unresolvable methodological rather classification problem, as seen from studies from countries with many years of experience in training and diagnostic test series. Thus, the evidence base is currently insufficient to mandate double reading of slides.

Oestrogen receptor gene (ESR1) amplification is frequent in endometrial carcinoma and its precursor lesions

Oestrogen receptor alpha (ER) plays a critical, diverse and not fully understood role in endometrial carcinoma. Most endometrial carcinomas express ER and some of these tumours respond favourably to anti-oestrogen therapy. On the other hand, tamoxifen therapy constitutes a major risk factor for endometrial carcinoma development. Amplification of the ESR1 gene encoding ER was recently shown to constitute a mechanism for ER over-expression in breast carcinoma. This study was designed to determine the potential role of ESR1 amplifications in endometrial carcinoma. Tissue microarrays of 368 endometrial carcinomas and large sections of 43 cases of endometrial hyperplasia were analysed for ESR1 gene amplification and ER protein expression by means of fluorescence in situ hybridization (FISH) and immunohistochemistry. FISH revealed ESR1 amplification in 40/176 (23%) cancers, 6/19 (32%) atypical complex hyperplasias, 3/10 (30%) complex hyperplasias without atypia and 2/14 (14%) simple hyperplasias without atypia. Strong ER protein expression was significantly linked to ESR1 amplification in endometrial carcinoma (p = 0.0036). These data indicate that ESR1 amplification might be one mechanism for ER over-expression in endometrial carcinoma, and suggest an early role for ESR1 amplification in the development of a significant fraction of endometrial carcinoma. Given the predictive role of ESR1 amplification for tamoxifen response in breast carcinoma, it will be interesting to investigate the response of ESR1-amplified endometrial cancers to anti-oestrogenic drugs.

Prognostische Faktoren beim duktalen Carcinoma in situ

Ductal carcinoma in situ (DCIS) is a heterogeneous disease that progresses to invasive cancer in 30-50% of the patients. Its natural history is poorly defined so that we are unable to identify cases of DCIS that do not progress to invasive carcinoma during an individual's lifetime. However, pathologic features of DCIS are nowadays the basis for the estimation of the prognosis and planning of therapy. Exclusion of microinvasion, characterization of nuclear grade, architecture, size and distribution of the DCIS, presence or absence of comedonecrosis as well as the assessment of surgical margins are relevant factors for local treatment. The determination of steroid hormone receptor status is indicated in patients considering tamoxifen therapy after breast conservation. It is advisable to evaluate the features according to internationally accepted guidelines with proven prognostic relevance and reproducibility. Nevertheless, better prognostic factors are needed to adapt the management of this increasingly diagnosed disease to the individual patient.

[Experiences of the Bavarian mammography screening program]

The Bavarian Mammography Screening Program started in April 2003. A detailed analysis of the consistency of diagnosis in the evaluation of vacuum-assisted stereotactic or core needle breast biopsies is presented. A total of 32 pathologists participated in a blinded evaluation of the biopsies. Each case was evaluated independently by two participating pathologists. A total of 1,357 cases were reviewed. The histopathological reports of the biopsies made by the two consulting pathologists were compared. The concordance rate of the first and second consulting pathologist was 93% for the B-classification. In general, the level of diagnostic agreement was very high for well defined, benign and malignant lesions. Some of the discrepancies resulted from the incorrect application of the B-classification. Discrepancies in the reports were also due to divergent interpretation of benign and "borderline" lesions. The protocol for the blinded evaluation of breast biopsies in two rounds assured a high level of quality. In conclusion, prerequisites for the success of a mammography screening program are interdisciplinary consensus conferences and audit rounds involving pathologists.

Are we wasting our time with the sentinel technique? Fifteen reasons to stop axilla dissection

Originally, surgery for breast cancer involved removing the pectoral muscles and the regional lymph nodes. This drastic technique was based on Halsted's paradigm of continuous tumour spread via the lymph nodes. In the last century, the amount of surgery has gradually decreased as breast cancer has been recognised as a primary systemic, or partially systemic, disease. Nowadays, breast-conserving therapy is widely used, but axillary lymph node dissection (ALND) and the sentinel technique are still common. Can the patient also be spared such axillary surgery? We have assembled convincing arguments against ALND (and therefore also against the sentinel technique) based on the probability that positive lymph nodes are unlikely to metastasise and that removing them is redundant. At least a discussion of this topic is more than overdue, even if it may be too early to change behaviour.

HgCl2 challenge in Brown Norway rats lead to dermatitis instead of arthritis

A wide range of methods are described to produce adjuvant arthritis in rats by antigen exposure. Studies using these methods are rarely controlled histologically though the result can be paw dermatitis instead of arthritis. Three male Brown Norway rats were injected s.c. with HgCl2 (1 mg Hg/kg body weight) on five alternating days following closely a well described scheme for induction of adjuvant arthritis. Extent of paw oedema was assessed sonographically. Location and extent of inflammatory responses were inspected histologically. Swollen reddish and painful paw oedema started to develop on day 13 increasing until day 16. Oedema increased skin-to-bone and skin-to-skin distance across the inflamed paws significantly. Histological examination on day 16 revealed marked dermatitis with dense cellular infiltrates, single cell necrosis and fibrin exudation. In contrast, no inflammatory responses were observed in the joints. Use of a well described scheme for induction of adjuvant arthritis produced dermatitis of the paw with identical time course, clinical and sonographic appearance as expected for arthritis. This observation strongly suggests the need to check the histology on location and the kind of inflammatory response when a model for adjuvant arthritis is altered or used for the first time.

[Recent therapeutic options and expectations to the pathologist]

The treatment of patients with breast cancer has progressively become multidisciplinary. Considering that the establishment of standards of care for medical treatment is a process of building consensus by using the best available scientific evidence, multidisciplinary guidelines have been developed in Germany to promote better and more consistent management of breast cancer patients (www.krebsgesellschaft.de). These guidelines provide a framework for clinical decision-making and pathological assessment that gives clinically useful and prognostically significant information. The improvement of standards of care is subject to the definition of procedures at the interface between the different involved disciplines. The following topics at the surgery-pathology interface are critical for the optimal management of breast cancer and should be coordinated, especially with regard to breast conserving therapy: 1. Unequivocal marking of the tissue specimens by the surgeon in order to obtain proper orientation. 2. Intra-operative frozen sectioning. 3. Residual tumour (R) classification (UICC, 2002) and adequate distance to resection margins (for DCIS and invasive carcinomas). 4. Specific requirements on the pathological examination of surgical specimens after primary systemic treatment (neoadjuvant chemotherapy), i. e. the assessment of tumour response and the extent and distribution of tumour residues.

Blockade of 12-lipoxygenase expression protects cortical neurons from apoptosis induced by β-amyloid peptide

The cyclo-oxygenase (COX) and lipoxygenase (LOX) pathways belong to the eicosanoid synthesis pathway, a major component of the chronic inflammatory process occurring in Alzheimer's disease (AD). Clinical studies reported beneficial effects of COX inhibitors, but little is known about the involvement of LOXs in AD pathogenesis. beta-amyloid peptide (A beta) accumulation contributes to neurodegeneration in AD, but mechanisms underlying A beta toxicity have not been fully elucidated yet. Here, using an antisense oligonucleotide-based strategy, we show that blockade of 12-LOX expression prevents both A beta-induced apoptosis and overexpression of c-Jun, a factor required for the apoptotic process, in cortical neurons. Conversely, the 12-LOX metabolite, 12(S)-HETE (12(S)-hydroxy-(5Z, 8Z, 10E, 14Z)-eicosatetraenoic acid), promoted c-Jun-dependent apoptosis. Specificity of the 12-LOX involvement was further supported by the observed lack of contribution of 5-LOX in this process. These data indicate that blockade of 12-LOX expression disrupts a c-Jun-dependent apoptosis pathway, and suggest that 12-LOX may represent a new target for the treatment of AD.

Fibroadenoma of the breast in an 11-year-old girl

Fibroadenoma is the main cause of unilateral breast mass in teenagers and adolescents. 4% of these are a special form described as giant or juvenile fibroadenoma. For primary diagnosis, ultrasound is the method of choice. The MRI allows exact evaluation of size and location. The fibroadenoma must be distinguished from the phylloid tumour, which can be malignant. The latter occurs in patients of all ages, but peaks between the ages 40 and 50 years. Only 2% of all primary malignant breast lesions are found in women aged under 25. Metastases of other primary tumours must be excluded, especially with a history of prior malignancies. When planning the surgical excision, the final cosmetic result is important. Although the main reason of an asymmetrical breast enlargement of young girls is a benign mass, an early surgical excision is efficient with regard to the best possible cosmetic outcome.