Updated 2013 College of American Pathologists/American Society of Clinical Oncology (CAP/ASCO) guideline recommendations for human epidermal growth factor receptor 2 (HER2) fluorescent in situ hybridization (FISH) testing increase HER2 positive and HER2 equivocal breast cancer cases; retrospective study of HER2 FISH results of 836 invasive breast cancers

The impact of PIK3CA mutations and PTEN expression on the effect of neoadjuvant therapy for postmenopausal luminal breast cancer patients

BACKGROUND

There is pressing needs to find the biomarker in the selection of neoadjuvant therapy in postmenopausal luminal breast cancer patients. We examined the hypothesis that PIK3CA mutations and low phosphatase and tensin homolog (PTEN) expression affect the response to neoadjuvant therapy and prognosis in postmenopausal luminal breast cancer patients.

METHODS

Postmenopausal patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, up to stage II, who underwent neoadjuvant chemotherapy (NAC; n = 60) or neoadjuvant endocrine therapy (NAE; n = 55) were selected. PIK3CA exon 9 and exon 20 mutations were screened by high resolution melting analysis and confirmed by Sanger sequence. PTEN expression was evaluated by immunohistochemistry. The relationships among PIK3CA mutations, PTEN expression, clinicopathological features, the pathological effect of neoadjuvant therapy, recurrence-free survival (RFS) and overall survival were analyzed.

RESULTS

Among 115 patients, PIK3CA mutations and low PTEN expression before treatment were detected in 35 patients (30.4%) and in 28 patients (24.3%), respectively. In the NAC group, tumor with PIK3CA mutations showed significantly poorer response than tumor with PIK3CA wild-type (p = 0.03). On the other hand, in the NAE group, there was no significant difference in pathological therapeutic effect between tumor with PIK3CA mutations and tumor with PIK3CA wild-type (p = 0.54). In the NAC group, the log-rank test showed no difference in RFS between patients with PIK3CA mutations and PIK3CA wild-type (p = 0.43), but patients with low PTEN expression showed significantly worse RFS compared to patients with high PTEN expression (5 year RFS 0.64 vs. 0.87, p = 0.01). In the Cox proportional hazards model for RFS, PTEN expression, progesterone receptor, and pathological therapeutic effect were predictive factors for time to recurrence (All p < 0.05).

CONCLUSIONS

PIK3CA mutations are associated with resistance to NAC but do not affect the response to NAE. Low PTEN expression does not affect response to either NAC or NAE but correlates with shorter RFS in patients who received NAC. These biomarkers will be further evaluated for clinical use to treat postmenopausal luminal breast cancer patients.

CMTM6 overexpression confers trastuzumab resistance in HER2-positive breast cancer

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer is characterized by invasive growth, rapid metastasis and chemoresistance. Trastuzumab is an effective treatment for HER2+ breast cancer; however, trastuzumab resistance leads to cancer relapse and metastasis. CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) has been considered as a new immune checkpoint for tumor-induced immunosuppression. The role of CMTM6 in trastuzumab resistance remains unknown. Here, we uncover a role of CMTM6 in trastuzumab-resistant HER2+ breast cancer. CMTM6 expression was upregulated in trastuzumab-resistant HER2+ breast cancer cell. Patients with high CMTM6 expressing HER2+ breast cancer had worse overall and progression-free survival than those with low CMTM6 expression. In vitro, CMTM6 knockdown inhibited the proliferation and migration of HER2+ breast cancer cells, and promoted their apoptosis, while CMTM6 overexpression reversed these effects. CMTM6 and HER2 proteins were co-localized on the surface of breast cancer cells, and CMTM6 silencing reduced HER2 protein levels in breast cancer cells. Co-immunoprecipitation revealed that CMTM6 directly interacted with HER2 in HER2+ breast cancer cells, and CMTM6 overexpression inhibited HER2 ubiquitination. Collectively, these findings highlight that CMTM6 stabilizes HER2 protein, contributing to trastuzumab resistance and implicate CMTM6 as a potential prognostic marker and therapeutic target for overcoming trastuzumab resistance in HER2+ breast cancer.

Microbiota of Breast Tissue and Its Potential Association with Regional Recurrence of Breast Cancer in Korean Women

Recent studies have reported dysbiosis of the microbiome in breast tissue collected from patients with breast cancer and the association between the microbiota and disease progression. However, the role of the microbiota in breast tissue remains unclear, possibly due to the complexity of breast cancer and various factors, including racial and geographical differences, influencing microbiota in breast tissue. Here, to determine the potential role of microbiota in breast tumor tissue, we analyzed 141 tissue samples based on three different tissue types (tumor, adjacent normal, and lymph node tissues) from the same patients with breast cancer in Korea. The microbiota was not simply distinguishable based on tissue types. However, the microbiota could be divided into two cluster types, even within the same tissue type, and the clinicopathologic factors were differently correlated in the two cluster types. Risk of regional recurrence was also significantly different between the microbiota cluster types (p = 0.014). In predicted function analysis, the pentose and glucuronate interconversions were significantly different between the cluster types (q < 0.001), and Enterococcus was the main genus contributing to these differences (q < 0.01). Results showed that the microbiota of breast tissue could interact with the host and influence the risk of regional recurrence. Although further studies would be recommended to validate our results, this study could expand our understanding on the breast tissue microbiota, and the results might be applied to develop novel prediction methods and treatments for patients with breast cancer.

MRI Response to Pre-operative Stereotactic Ablative Body Radiotherapy (SABR) in Early Stage ER/PR+ HER2- Breast Cancer correlates with Surgical Pathology Tumor Bed Cellularity

OBJECTIVE

This study evaluates breast MRI response of ER/PR+ HER2- breast tumors to pre-operative SABR with pathologic response correlation.

METHODS

Women enrolled in a phase 2 single institution trial of SABR for ER/PR+ HER2- breast cancer were retrospectively evaluated for radiologic-pathologic correlation of tumor response. These patients underwent baseline breast MRI, SABR (28.5 Gy in 3 fractions), follow-up MRI 5 to 6 weeks post-SABR, and lumpectomy. Tumor size and BI-RADS descriptors on pre and post-SABR breast MRIs were compared to determine correlation with surgical specimen % tumor cellularity (%TC). Reported MRI tumor dimensions were used to calculate percent cubic volume remaining (%VR). Partial MRI response was defined as a BI-RADs descriptor change or %VR ≤ 70%, while partial pathologic response (pPR) was defined as %TC ≤ 70%.

RESULTS

Nineteen patients completed the trial, and %TC ranged 10% to 80%. For BI-RADS descriptor analysis, 12 of 19 (63%) showed change in lesion or kinetic enhancement descriptors post-SABR. This was associated with lower %TC (29% vs. 47%, P = .042). BI-RADS descriptor change analysis also demonstrated high PPV (100%) and specificity (100%) for predicting pPR to treatment (sensitivity 71%, accuracy 74%), but low NPV (29%). MRI %VR demonstrated strong linear correlation with %TC (R = 0.70, P < .001, Pearson's Correlation) and high accuracy (89%) for predicting pPR (sensitivity 88%, specificity 100%, PPV 100%, and NPV 50%).

CONCLUSION

Evaluating breast cancer response on MRI using %VR after pre-operative SABR treatment can help identify patients benefiting the most from neoadjuvant radiation treatment of their ER/PR+ HER2- tumors, a group in which pCR to neoadjuvant therapy is rare.

Aptamer-based sensing of breast cancer biomarkers: a comprehensive review of analytical figures of merit

INTRODUCTION

Accurate determination of the aberrantly expressed biomarkers such as human epidermal growth factor receptor 2 (HER2), carcinoembryonic antigen (CEA), platelet-derived growth factor (PDGF), mucin 1 (MUC1), and vascular endothelial growth factor VEGF₁₆₅ have played an essential role in the clinical management of the breast cancer. Assessment of these cancer-specific biomarkers has conventionally relied on time-taking methods like the enzyme-linked immunosorbent assay and immunohistochemistry. However, recent development in the aptamer-based diagnostics has allowed developing tools that may substitute the conventional means of biomarker assessment in breast cancer. Adopting the aptamer-based diagnostic tools (aptasensors) to clinical practices will depend on their analytical performance on clinical samples.

AREAS COVERED

In this review, we provide an overview of the analytical merits of HER2, CEA, PDGF, MUC1, and VEGF₁₆₅ aptasensors. Scopus and Pubmed databases were searched for studies reporting aptasensor development for the listed breast cancer biomarkers in the past one decade. Linearity, detection limit, and response time are emphasized.

EXPERT OPINION

In our opinion, aptasensors have proven to be on a par with the antibody-based methods for detection of various breast cancer biomarkers. Though robust validation of the aptasensors on significant sample size is required, their ability to detect pathophysiological range of biomarkers suggest the possibility of future clinical adoption.

Effects of Ado-Trastuzumab Emtansine and Fam-Trastuzumab Deruxtecan on Metastatic Breast Cancer Harboring HER2 Amplification and the L755S Mutation

Somatic mutations in human epidermal growth factor receptor 2 (HER2) are present in approximately 3% of breast cancers. Some HER2 mutations are activating, and they represent a mechanism of resistance to conventional anti-HER2 therapies such as trastuzumab and lapatinib. Consistently, in patients with HER2-amplified breast cancer, these mutations are predominantly observed in metastatic tumors obtained after exposure to anti-HER2 systemic therapies, possibly after clonal selection. Therefore, it is rare to find coexistent HER2 mutation and amplification in the early clinical course, and thus, the clinical relevance of HER2 mutation to the sensitivity to HER2-targeted drugs, particularly antibody-drug conjugates (ADCs) such as ado-trastuzumab emtansine (T-DM1) and the recently approved fam-trastuzumab deruxtecan (T-DXd), remains unclear. In this article, we describe a patient with de novo metastatic breast cancer who exhibited both HER2 amplification and the L755S mutation in the untreated primary breast tumor obtained at the initial diagnosis, and the lesion responded to T-DM1 and T-DXd after exhibiting clinical resistance to other HER2-targeted drugs. Our current case findings suggested that anti-HER2 ADCs should be prioritized over conventional trastuzumab- or lapatinib-based therapies for patients with HER2-amplified and comutated tumors. KEY POINTS: Although HER2 mutations were implicated in resistance to anti-HER2 monoclonal antibodies or HER2 tyrosine kinase inhibitors in preclinical studies, their clinical impact on sensitivity to anti-HER2 drugs is unclear owing to the rarity of concomitant HER2 mutation and HER2 amplification. A case of de novo metastatic breast cancer harboring both HER2 amplification and the L755S mutation in an untreated breast primary tumor displayed clinical resistance to standard trastuzumab- or lapatinib-based therapies but good responses to ado-trastuzumab emtansine (T-DM1) and fam-trastuzumab deruxtecan (T-DXd). Anti-HER2 antibody-drug conjugates such as T-DM1 and T-DXd may be prioritized over conventional trastuzumab- or lapatinib-containing therapies for patients with HER2-amplified and comutated tumors.

The implementation of a commercially available multi-gene profile test for breast cancer characterization in a department of pathology: what have we learned from the first 100 cases?

Analysis of breast cancer prognostic and predictive factors is still nowadays poorly accurate and standardized. The advent of multi-gene expression profiles (MGEPs) has improved the prediction of breast cancer outcome, particularly regarding early luminal breast cancers (LBCs). The availability in our Institute of EndoPredict® (EP), a last-generation prognostic gene signature assay, has prompted us to study a series of LBCs, firstly verifying its reproducibility on six routine representative cases, either presenting non-optimal preanalytical conditions or different tumor samples from the same patient; secondly, correlating EP results on 8 retrospectively recruited samples with patients' follow-up; thirdly, applying prospectively EP on 100 routinely diagnosed cases, assessing the oncologists' and pathologists' attitude toward it. The complete reproducibility of EP on all the samples investigated in the first phase allowed to state that EP overcomes the detrimental effects of an inaccurate pre-analytic phase, determining the most appropriate prognostic and predictive parameters of breast cancer. The second phase confirmed EP as a fundamental tool in guiding therapeutic decision, improving the classical bio-pathological characterization and recovering 38% patients' inadequately managed. Finally, the study disclosed how oncologists sometimes inadequately requested EP, but also how it allows a better stratification of breast cancer otherwise considered poorly aggressive and not requiring an EP test, such as G1 neoplasms or tubular histotype. In conclusion, the introduction of EP test in an Anatomic Pathology Department emerges as a useful tool in routine breast cancer diagnosis, both for the characterization of individual cases and, as a result, for more appropriate therapeutic choices.

Immune profiling and immunotherapeutic targets in pancreatic cancer

Background

Immunotherapeutic approaches for pancreatic ductal adenocarcinoma (PDAC) are less successful as compared to many other tumor types. In this study, comprehensive immune profiling was performed in order to identify novel, potentially actionable targets for immunotherapy.

Methods

Formalin-fixed paraffin embedded (FFPE) specimens from 68 patients were evaluated for expression of 395 immune-related markers (RNA-seq), mutational burden by complete exon sequencing of 409 genes, PD-L1 expression by immunohistochemistry (IHC), pattern of tumor infiltrating lymphocytes (TILs) infiltration by CD8 IHC, and PD-L1/L2 copy number by fluorescent in situ hybridization (FISH).

Results

The seven classes of actionable genes capturing myeloid immunosuppression, metabolic immunosuppression, alternative checkpoint blockade, CTLA-4 immune checkpoint, immune infiltrate, and programmed cell death 1 (PD-1) axis immune checkpoint, discerned 5 unique clinically relevant immunosuppression expression profiles (from most to least common): (I) combined myeloid and metabolic immunosuppression [affecting 25 of 68 patients (36.8%)], (II) multiple immunosuppressive mechanisms (29.4%), (III) PD-L1 positive (20.6%), (IV) highly inflamed PD-L1 negative (10.3%); and (V) immune desert (2.9%). The Wilcoxon rank-sum test was used to compare the PDAC cohort with a comparison cohort (n=1,416 patients) for the mean expressions of the 409 genes evaluated. Multiple genes including TIM3, VISTA, CCL2, CCR2, TGFB1, CD73, and CD39 had significantly higher mean expression versus the comparison cohort, while three genes (LAG3, GITR, CD38) had significantly lower mean expression.

Conclusions

This study demonstrates that a clinically relevant unique profile of immune markers can be identified in PDAC and be used as a roadmap for personalized immunotherapeutic decision-making strategies.

Impact of the Updated 2018 American Society of Clinical Oncology/College of American Pathologists Guideline for Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer

CONTEXT.—

The updated American Society of Clinical Oncology/College of American Pathologists guideline for human epidermal growth factor receptor 2 (HER2) testing in breast cancer requires pathologists to re-evaluate HER2 status.

OBJECTIVE.—

To define HER2 status of breast cancer using immunohistochemistry and fluorescence in situ hybridization.

DESIGN.—

Diagnostic reports of invasive breast cancers made between 2014 and 2018 with HER2 immunohistochemistry and fluorescence in situ hybridization results were retrieved. HER2 status was re-defined using the updated recommendations.

RESULTS.—

Of 2514 tumors, 89.7% (2254 of 2514) suggested for fluorescence in situ hybridization assay were HER2 immunohistochemistry 2+. Approximately 8.9% (225 of 2514) and 1.4% (35 of 2514) of tumors were of immunohistochemistry 0/1+ and 3+, respectively. Based on the average HER2 copy number and HER2:CEP17 ratio, tumors were assigned into 5 groups, including 13.1% (330 of 2514) group 1 tumors, 2.1% (52 of 2514) group 2 tumors, 1.1% (27 of 2514) group 3 tumors, 7.0% (175 of 2514) group 4 tumors, and 76.8% (1930 of 2514) group 5 tumors. In combination with immunohistochemistry, all tumors in group 2 and group 4 changed HER2 status, from positive and equivocal into negative, respectively, while group 3 tumors remained positive. Comparative analyses of clinicopathologic features of tumors in different groups revealed that group 2 and 4 tumors displayed worse clinicopathologic features than those of group 5, while group 3 tumors shared similar clinicopathologic features to those of group 1.

CONCLUSIONS.—

Following the updated guideline, HER2 status is clearly designated. Significant differences regarding clinical features were observed between tumors in different groups but they share the same HER2 status, suggesting further validation of the accuracy of this diagnostic approach is warranted.

Clinicopathologic features of breast cancer reclassified as HER2-amplified by fluorescence in situ hybridization with alternative chromosome 17 probes

OBJECTIVE

Dual probe fluorescence in situ hybridization (FISH) assays for determination of human epidermal growth factor receptor 2 (HER2) gene amplification in breast cancer provide a ratio of HER2 to chromosome 17. The ratio may be skewed by copy number alterations (CNA) in the control locus for chromosome 17 (CEP17). We analyzed the impact of alternative chromosome 17 control probes on HER2 status in a series of breast cancers with an emphasis on patients reclassified as amplified.

METHODS

Breast cancer patients with equivocal HER2 immunohistochemistry (2+) and equivocal FISH with CEP17 were included. Reclassification of HER2 status was assessed with alternative chromosome 17 control probes (LIS1 and RARA).

RESULTS

A total of 40 unique patients with 46 specimens reflexed to alternative chromosome 17 probe testing were identified. The majority (>80%) of patients had pT1-2, hormone receptor-positive tumors with an intermediate or high combined histologic grade. There were 34/46 (73.9%) specimens reclassified as amplified with alternative probes, corresponding to 29/40 (72.5%) patients. Of the patients reclassified as amplified with alternative probes, 34.5% (10/29) received HER2-targeted therapy.

CONCLUSION

In this series, the majority of breast cancers tested with alternative chromosome 17 control probes under the 2013 ASCO/CAP Guidelines were converted to HER2-amplified. The treatment data and the clinicopathologic profile of the tumors suggest that most of these patients will neither receive nor benefit from HER2-targeted therapy. The findings support the recommendation in the 2018 ASCO/CAP HER2 Guidelines to discontinue the use of alternative chromosome 17 probes.

Impact on survival of estrogen receptor, progesterone receptor and Ki-67 expression discordance pre- and post-neoadjuvant chemotherapy in breast cancer

PURPOSE

To investigate whether estrogen receptor (ER), progesterone receptor (PR) and Ki-67 expression discordance before and after neoadjuvant chemotherapy (NAC) correlates with prognosis and treatment of breast cancer patients.

METHODS

The study cohort included 482 breast cancer patients at the Zhejiang Cancer Hospital from January 1, 2008, to December 31, 2018. Core needle biopsies and excised tissue biopsies pre- and post-NAC were obtained. Immunohistochemistry was used to determine ER, PR and Ki-67 status. The relationship between biomarker discordance before and after NAC and clinicopathological features was compared retrospectively.

RESULTS

ER (n = 482), PR (n = 482) and Ki-67 (n = 448) expression was assessed in the same lesion pre- and post-NAC. Discordance in the three markers pre- and post-NAC was observed in 50 (10.4%), 82 (17.0%) and 373 (77.4%) cases, respectively. Positive-to-negative PR expression changes were the most common type of discordance observed. The risk of death in patients with a PR positive-to-negative conversion was 6.58 times greater than for patients with stable PR expression. The risk of death in patients with increased Ki-67 expression following NAC treatment was 2.05 times greater than for patients with stable Ki-67 expression.

CONCLUSION

Breast cancer patients showed changes in ER, PR and/or Ki-67 status throughout NAC, and these changes possibly influenced disease-free survival and overall survival. A switch to negative hormone receptor expression with increased Ki-67 expression following NAC could be indicators of a worse prognosis. Biomarker expression investigations following NAC may potentially improve patient management and survival.

The updated 2018 American Society of Clinical Oncology/College of American Pathologists guideline on human epidermal growth factor receptor 2 interpretation in breast cancer: comparison with previous guidelines and clinical significance of the proposed in situ hybridization groups

The aim of the study was to evaluate the impact of the updated 2018 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline on human epidermal growth factor receptor 2 (HER2) interpretation in breast cancer compared with that of the previous guidelines and also the significance of in situ hybridization (ISH) groups proposed by the updated guideline. HER2 ISH reports and immunohistochemistry (IHC) data from 1,348 invasive breast cancers diagnosed at a single institution were included in this study. HER2 IHC was reassessed using the 2018 guideline, and HER2 ISH status was determined by the 2007, 2013, and 2018 guidelines. When applying the updated guideline, most of the HER2 ISH-equivocal cases as per the previous guidelines were reclassified as ISH negative, and 0.8% of HER2 ISH-positive tumors as per the 2007 guideline and 2.5% of those as per the 2013 guideline were changed to ISH negative. Accordingly, the negative HER2 ISH results significantly increased in the 2018 guideline compared with the 2013 guideline. HER2 ISH-positive tumors in ISH group 3 (HER2/chromosome enumeration probe 17 [CEP17] ratio <2.0 and average HER2 copy number ≥6.0 per cell) were characterized by equivocal HER2 protein expression, CEP17 copy number gain, and low HER2 copy numbers compared with classic HER2 ISH-positive tumors in ISH group 1 (HER2/CEP17 ratio ≥2.0 and average HER2 copy number ≥4.0 per cell). HER2 ISH-negative tumors in ISH group 4 (HER2/CEP17 ratio <2.0 with average HER2 copy number ≥4.0 and < 6.0 per cell) revealed more aggressive clinicopathologic features and poorer clinical outcomes than those in ISH group 5 (HER2/CEP17 ratio <2.0 and average HER2 copy number <4.0 per cell), especially in the hormone receptor-positive subgroup. In conclusion, implementation of the updated 2018 ASCO/CAP guideline leads to a significant increase in HER2 ISH-negative results compared with the 2013 guideline, mainly via reclassification of the ISH-equivocal cases to ISH-negative ones. ISH groups proposed by the updated guideline provide additional information on the clinicopathologic characteristics of the tumors.

Impact of 2013 ASCO/CAP guidelines on various HER2 reporting categories in breast cancer by fluorescentin-situhybridization and Immunohistochemistry: A meta-analysis with systematic review

Objective:

The ASCO/CAP guidelines for reporting HER2 in breast cancer, first released in 2007, aimed to standardize the reporting protocol, and were updated in 2013 and 2018, to ensure right treatment. Several studies have analyzed the changes attributed to 2013 updated guidelines, and majority of them found increase in positive and equivocal cases. However, the precise implication of these updated guidelines is still contentious, in spite of the latest update (2018 guidelines) addressing some of the issues. We conducted systematic review and meta- analysis to see the impact of 2013 guidelines on various HER2 reporting categories by both FISH and IHC.

Materials and Methods:

After extensively searching the pertinent literature, 16 studies were included for the systematic review. We divided our approach in three strategies: (1) Studies in which breast cancer cases were scored for HER2 by FISH or IHC as a primary test concurrently by both 2007 and 2013 guidelines, (2) Studies in which HER2 results were equivocal by IHC and were followed by reflex-FISH test by both 2007 and 2013 guidelines, and (3) Studies in which trends of HER2 reporting were compared in the two periods before and after implementation of updated 2013 guidelines. All the paired data in these respective categories was pooled and analyzed statistically to see the overall impact of the updated guidelines.

Results:

In the first category, by pooled analysis of primary FISH testing there has been a significant increase in the equivocal cases (P< 0.001) and positive cases (P= 0.037). We also found 8.3% and 0.8% of all the negative cases from 2007 guidelines shifted to equivocal and positive categories, respectively. Similarly by primary IHC testing there has been a significant increase in both equivocal cases (P< 0.001) and positive cases (P= 0.02). In the second category of reflex-FISH testing there was a substantial increase in the equivocal cases (P< 0.0001); however there is insignificant decrease (10% to 9.7%;P= 0.66) in the amplified cases. In the third approach for evaluating the trend, with the implementation of 2013 guidelines, there was increase in the equivocal category (P= 0.025) and positive category (P= 0.0088) by IHC. By FISH test also there was significant increase in the equivocal category (P< 0.001) while the increase in the positive category was non-significant (P= 0.159).

Conclusions:

The updated 2013 guidelines has significantly increased the positive and equivocal cases using primary FISH or IHC test and with further reflex testing, thereby increasing the double equivocal cases and increasing the cost and delaying the decision for definite management. However, whether the additional patients becoming eligible for HDT will derive treatment benefit needs to be answered by further large clinical trials.

Implementation of the 2018 American Society of Clinical Oncology/College of American Pathologists Guidelines on HER2/neu Assessment by FISH in breast cancers: predicted impact in a single institutional cohort

The 2018 American Society of Clinical Oncology (ASCO) and College of American Pathologists (CAP) update modified the interpretation guidelines for human epidermal growth factor receptor 2 (HER2) testing by incorporating immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) results in a subset of cases. Importantly, the new guidelines eliminate "equivocal" results, as well as the use of alternative chromosome 17 probes as the primary strategy for resolving the indeterminate FISH results. Herein, we investigate the predicted impact of implementing the 2018 ASCO/CAP guidelines on HER2 assessment by FISH in breast cancers, using data from a single institution. We compared the HER2 status of 1542 consecutive cases of breast carcinoma, interpreted by 2013 and 2018 ASCO/CAP guidelines. In total, 10.7% (165/1542) of the cases had a different final interpretation by 2018 guidelines compared with 2013 guidelines, including 70 previously HER2-positive cases reclassified as negative, four previously negative cases reclassified as positive, and 91 previously equivocal cases reclassified as negative. Overall, the number of HER2-positive cancers was reduced by 66 cases (4.3% reduction in the HER2 positivity rate). The newly HER2-negative cases were mostly estrogen receptor positive (90%), progesterone receptor positive (80%), stage 1 (60.9%), and grade 1-2 (59.4%) cancers; 70% of them had been designated as HER2 positive only after the use of an alternative chromosome 17 FISH probe after an intially equivocal result from the standard CEP17 probe. Overall, implementing the revised 2018 HER2 guidelines is predicted to change the HER2 results of 10.7% of breast cancers, mainly by reclassifying previously equivocal to negative results.

Fast fluorescence in situ hybridisation for the enhanced detection of MET in non-small cell lung cancer

The c-Met/hepatocyte growth factor receptor pathway is frequently dysregulated in multiple cancer types, including non-small cell lung cancer (NSCLC). MET amplification has been shown to develop as a resistance mechanism to treatment in NSCLC. The identification of increased MET copy number within tumour cells is increasingly important to stratify those tumours and patients which are susceptible to treatment targetting MET kinase inhibition. Fluorescence in situ hybridisation (FISH) has been successfully employed to identify patients with abnormal MET gene copy number with numerous probes available for use. Here we report a FISH protocol that reduces probe hybridisation time in NSCLC tissue to 1 hour and compare the results with other protocols. MET gene copy number was determined in 20 NSCLC cases using 3 FISH probes: 1. Kreatech FISH, MET (7q31) SE 7 ready to use probes, hybridised using an overnight protocol; 2. Dako MET IQFISH probe with CEP7 ready to use probe, hybridised for 2 hours; 3. Kreatech MET (7q31) SE 7 XL FISH probe, prepared in SwiftFISH buffer and hybridised for 1 hour. The MET gene copy number and MET: centromere 7 gene ratio were determined for each tissue and cases categorised as having MET high or MET low status. All three FISH probes were shown to demonstrate good agreement with each other. Overall percentage agreement between probes was ≥90%. Intraclass correlation showed good agreement (ICC ≥0.80) between all three assays for MET gene copy number and MET: centromere 7 gene ratio. These FISH protocols provide evidence that rapid laboratory developed FISH assays with short turnaround time perform consistently with standard protocols, potentially enabling faster treatment decisions.

The FDA-Approved Breast Cancer HER2 Evaluation Kit (HercepTest; Dako) May Miss Some HER2-Positive Breast Cancers

OBJECTIVES

Accurate evaluation of human epidermal growth factor receptor 2 (HER2) in breast cancer is critical.

METHODS

HER2 fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) tests were performed on 52 cases using a US Food and Drug Administration (FDA)-approved kit (HercepTest, FDA kit) and a laboratory-developed test (LDT) with the HercepTest antibody and a Leica Bond automated stainer.

RESULTS

By FISH, 22 were HER2 positive, 29 were negative, and one was equivocal. Of the 22 HER2 FISH-positive cases, five were negative by the FDA kit and none by LDT. The five discrepant cases were retested using the same FDA kit in another Clinical Laboratory Improvement Amendments-certified laboratory, and all five cases were still negative. None of the 29 HER2 FISH-negative cases were positive by the FDA kit or LDT. The overall IHC-FISH concordance rate was 90.4% for the FDA kit and 100% for the LDT.

CONCLUSIONS

The FDA kit may miss some HER2-positive cases. The LDT has a higher sensitivity and a higher concordance rate with FISH results.

Relationship between Ribosomal Protein S6-pS240 Expression and other Prognostic Factors in Non-Special Type Invasive Breast Cancer

Background

The aim of this study was to investigate the immunohistochemical expression of ribosomal protein (RP) S6-pS240 in non-special type invasive breast cancer in relation to other prognostic markers and gain new insights to facilitate more individualized treatment.

Methods

The following clinical and histopathological parameters of 120 patients were determined: S6-pS240 expression, age, menopausal status, tumor size and grade, TNM stage, Nottingham Prognostic Index (NPI), lymph node stage, estrogen and progesterone receptor (ER/PR) expression, HER2/neu amplification, lymphovascular invasion, and proliferative index as measured by Ki-67. Treatment protocol and disease-free survival were evaluated accordingly.

Results

Significant positive correlations were seen between S6-pS240 expression and Ki-67 values (rho = 0.530, p < 0.001), and NPI (rho = 0.370, p < 0.001) and HER2/neu amplification (rho = 0.368, p < 0.001). A negative correlation was found between S6-pS240 and ER/PR expression (rho = 0.362, p < 0.001). Patients with negative RP S6-pS240 expression had significantly longer disease-free survival (log-rank test, p = 0.005).

Conclusion

Immunohistochemical analysis of RP S6-pS240 is a valuable additional prognostic marker in patients with invasive breast cancer. Routine use of S6-pS240 immunohistochemistry is recommended.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update

PURPOSE.—

To update key recommendations of the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) human epidermal growth factor receptor 2 (HER2) testing in breast cancer guideline.

METHODS.—

Based on the signals approach, an Expert Panel reviewed published literature and research survey results on the observed frequency of less common in situ hybridization (ISH) patterns to update the recommendations.

RECOMMENDATIONS.—

Two recommendations addressed via correspondence in 2015 are included. First, immunohistochemistry (IHC) 2+ is defined as invasive breast cancer with weak to moderate complete membrane staining observed in >10% of tumor cells. Second, if the initial HER2 test result in a core needle biopsy specimen of a primary breast cancer is negative, a new HER2 test may (not "must") be ordered on the excision specimen based on specific clinical criteria. The HER2 testing algorithm for breast cancer is updated to address the recommended workup for less common clinical scenarios (approximately 5% of cases) observed when using a dual-probe ISH assay. These scenarios are described as ISH group 2 ( HER2/chromosome enumeration probe 17 [CEP17] ratio ≥2.0; average HER2 copy number <4.0 signals per cell), ISH group 3 ( HER2/CEP17 ratio <2.0; average HER2 copy number ≥6.0 signals per cell), and ISH group 4 ( HER2/CEP17 ratio <2.0; average HER2 copy number ≥4.0 and <6.0 signals per cell). The diagnostic approach includes more rigorous interpretation criteria for ISH and requires concomitant IHC review for dual-probe ISH groups 2 to 4 to arrive at the most accurate HER2 status designation (positive or negative) based on combined interpretation of the ISH and IHC assays. The Expert Panel recommends that laboratories using single-probe ISH assays include concomitant IHC review as part of the interpretation of all single-probe ISH assay results.

First-in-human phase 0 study of 111In-CHX-A"-DTPA trastuzumab for HER2 tumor imaging

Introduction:

Tumors over-expressing the human epithelial receptor 2 (HER2) or exhibiting amplification or mutation of its proto-oncogene have a poorer prognosis. Using trastuzumab and/or other HER2 targeted therapies can increase overall survival in patients with HER2(+) tumors making it critical to accurately identify patients who may benefit. We report on a Phase 0 study of the imaging agent, ¹¹¹In-CHX-A”-DTPA trastuzumab, in patients with known HER2 status to evaluate its safety and biodistribution and to obtain preliminary data regarding its ability to provide an accurate, whole-body, non-invasive means to determine HER2 status.

Methods:

¹¹¹In-CHX-A”-DTPA trastuzumab was radiolabeled on-site and slowly infused into 11 patients who underwent single (n=5) or multiple (n=6) ɣ-camera (n=6) and/or SPECT (n=8) imaging sessions.

Results:

No safety issues were identified. Visual and semi-quantitative imaging data were concordant with tissue HER2 expression profiling in all but 1 patient. The biodistribution showed intense peak liver activity at the initial imaging timepoint (3.3h) and a single-phase clearance fit of the average time-activity curve (TAC) estimated t_1/2=46.9h (R²=0.97; 95%CI 41.8 to 53h). This was followed by high gastrointestinal (GI) tract activity peaking by 52h. Linear regression predicted GI clearance by 201.2h (R² =0.96; 95%CI 188.5 to 216.9h). Blood pool had lower activity with its maximum on the initial images. Non-linear regression fit projected a t_1/2=34.2h (R² =0.96; 95%CI 25.3 to 46.3h). Assuming linear whole-body clearance, linear regression projected complete elimination (x-intercept) at 256.5hr (R²=0.96; 95%CI 186.1 to 489.2h).

Conclusion:

¹¹¹In-CHX-A”-DTPA trastuzumab can be safely imaged in humans. The biodistribution allowed for visual and semiquantitative analysis with results concordant with tissue expression profiling in 10 of 11 patients. Advances in Knowledge and Implications for Patient Care Using readily available components and on-site radiolabeling ¹¹¹In-CHX-A”-DTPA trastuzumab SPECT imaging may provide an economical, non-invasive means to detect HER2 over-expression.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update

Purpose To update key recommendations of the American Society of Clinical Oncology/College of American Pathologists human epidermal growth factor receptor 2 (HER2) testing in breast cancer guideline. Methods Based on the signals approach, an Expert Panel reviewed published literature and research survey results on the observed frequency of less common in situ hybridization (ISH) patterns to update the recommendations. Recommendations Two recommendations addressed via correspondence in 2015 are included. First, immunohistochemistry (IHC) 2+ is defined as invasive breast cancer with weak to moderate complete membrane staining observed in > 10% of tumor cells. Second, if the initial HER2 test result in a core needle biopsy specimen of a primary breast cancer is negative, a new HER2 test may (not "must") be ordered on the excision specimen based on specific clinical criteria. The HER2 testing algorithm for breast cancer is updated to address the recommended work-up for less common clinical scenarios (approximately 5% of cases) observed when using a dual-probe ISH assay. These scenarios are described as ISH group 2 ( HER2/chromosome enumeration probe 17 [CEP17] ratio ≥ 2.0; average HER2 copy number < 4.0 signals per cell), ISH group 3 ( HER2/CEP17 ratio < 2.0; average HER2 copy number ≥ 6.0 signals per cell), and ISH group 4 ( HER2/CEP17 ratio < 2.0; average HER2 copy number ≥ 4.0 and < 6.0 signals per cell). The diagnostic approach includes more rigorous interpretation criteria for ISH and requires concomitant IHC review for dual-probe ISH groups 2 to 4 to arrive at the most accurate HER2 status designation (positive or negative) based on combined interpretation of the ISH and IHC assays. The Expert Panel recommends that laboratories using single-probe ISH assays include concomitant IHC review as part of the interpretation of all single-probe ISH assay results. Find additional information at www.asco.org/breast-cancer-guidelines .

Precise ERBB2 copy number assessment in breast cancer by means of molecular inversion probe array analysis

HER2/ERBB2 amplification/overexpression determines the eligibility of breast cancer patients to HER2-targeted therapy. This study evaluates the agreement between ERBB2 copy number assessment by fluorescence in situ hybridization, a standard method recommended by the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP), and newly available DNA extraction-based methods. A series of n=29 formalin-fixed paraffin-embedded breast cancers were subjected to ERBB2 copy number assessment by fluorescence in situ hybridization (FISH, Vysis, Abbott). Following macrodissection of invasive breast cancer tissue and DNA extraction, ERBB2 copy number was also determined by molecular inversion probe array analysis (MIP, OncoScan, Affymetrix) and next generation sequencing combined with normalized amplicon coverage analysis (NGS/NAC, AmpliSeq, Ion Torrent). ERBB2 copy number values obtained by MIP or NGS/NAC were tightly correlated with ERBB2 copy number values obtained by conventional FISH (r_s = 0.940 and r_s = 0.894, P < 0.001). Using ASCO/CAP guideline-conform thresholds for categorization of breast cancers as HER2-negative, equivocal or positive, nearly perfect concordance was observed for HER2 classification by FISH and MIP (93% concordant classifications, κ = 0.87). Substantial concordance was observed for FISH and NGS/NAC (83% concordant classifications, κ = 0.62). In conclusion, MIP facilitates precise ERBB2 copy number detection and should be considered as an ancillary method for clinical HER2 testing.

Utility of Alternate, Noncentromeric Chromosome 17 Reference Probe for Human Epidermal Growth Factor Receptor Fluorescence In Situ Hybridization Testing in Breast Cancer Cases

Context PathVysion-a US Food and Drug Administration-approved dual-probe human epidermal growth factor receptor ( HER2) fluorescence in situ hybridization (FISH) assay-provides the HER2: CEP17 ratio, a centromeric enumeration probe ratio for determining HER2 status in breast cancers. However, pericentromeric amplifications might then skew the HER2: CEP17 ratio, underestimating the HER2 status, which calls into question the use of CEP17 as the reference probe. Objective To analyze the utility of a noncentromeric chromosome 17 reference locus ( D17S122) to assess HER2 gene status in cases showing "nonclassical" FISH patterns with the CEP17 probe. Design The HER2 status of breast cancers accessioned in the years 2015-2017, displaying "nonclassical" or "equivocal" results by the PathVysion (Abbott Molecular Inc, Des Plaines, Illinois) HER2 DNA Probe Kit were reflex tested using an alternate FISH probe (ZytoLight SPEC/D17S122, ZytoVision, Bremerhaven, Germany) and interpreted with American Society of Clinical Oncology/College of American Pathologists 2013 guidelines. Results Of 37 cases, 17 were FISH equivocal. With the alternate D17S122 probe, 13 (76.4%) were reclassified as amplified, 3 (17.6%) as nonamplified, and a single case retained an equivocal result. Of the 17 cases with a chromosome 17 polysomy pattern, disomy, polysomy, and monosomy patterns were seen with 14 cases, 2 cases, and 1 case, respectively. Within the 17 cases with polysomy pattern, 3 (17.6%) demonstrated an unusual colocalization pattern of HER2 and CEP17, which was not observed with the alternate probe. Conclusions The denominator-stable alternate probe is a useful adjunct in the diagnostic armamentarium to analyze HER2 status in cases with FISH equivocal and complex patterns.

Regional Variability in Percentage of Breast Cancers Reported as Positive for HER2 in California: Implications of Patient Demographics on Laboratory Benchmarks

OBJECTIVES

The expected regional variability in percent human epidermal growth factor receptor 2 (HER2)-positive breast cancers is not currently clear.

METHODS

Data from the 2006 to 2011 California Cancer Registry were examined by county and health service area. The influence of demographic and pathologic features was used in a multivariable logistic regression model to compare expected with observed HER2-positive percentages by region.

RESULTS

There was significant geographic variation by California counties (11.6%-26%). The reported HER2-positive percentage was higher when the population had higher stage, tumor size, grade, percent estrogen receptor negative, younger age, or lower socioeconomic status. Ethnic distribution of the population also influenced HER2-positive percentages. Using a multivariable logistic regression model, most regions had expected values based on their population characteristics; however, "outlier" regions were identified.

CONCLUSIONS

These results deepen our understanding of population characteristics' influence on the distribution of HER2-positive breast cancers. Taking these factors into account can be useful when setting laboratory benchmarks and assessing test quality.

Impact of repeat HER2 testing after initial equivocal HER2 FISH results using 2013 ASCO/CAP guidelines

PURPOSE

The updated 2013 American Society of Clinical Oncology/College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 (HER2) testing have made some major changes in HER2 fluorescence in situ hybridization (FISH) interpretation criteria with additional FISH equivocal cases. Repeat HER2 testing is recommended after initial HER2 FISH equivocal results; however, little is known about its impact on final HER2 status. The aim of this study is to investigate whether reflex test clarifies HER2 status, and to characterize clinicopathological features of the newly defined HER2 equivocal group.

METHODS

A total of 886 consecutive cases of primary invasive breast cancer conducted with dual-probe HER2 FISH testing between November 2013 and December 2015 were reviewed. HER2 immunohistochemistry (IHC) and FISH testing were performed on a different tissue block or a new specimen after initial HER2 FISH equivocal results.

RESULTS

Compared to 2007 guideline, 85 (9.6%) cases changed their category by using 2013 guideline. The major change of the 85 cases is that 57 (6.4%) cases in HER2 FISH-negative category changed to equivocal, and the equivocal category cases increased from 36 to 67. HER2 FISH equivocal was significantly associated with HER2 IHC equivocal (2+) and chromosome 17 polysomy (P < 0.01). Repeat testing by IHC and FISH clarified HER2 status in 33 and 42% of HER2 equivocal cases, respectively. Overall 32 (48%) initial HER2 equivocal cases stayed HER2 equivocal after repeat FISH and or IHC testing. These tumors were ER/PR+, with high KI-67 index.

CONCLUSION

New guidelines classify more HER2 FISH equivocal cases. Repeat HER2 testing clarifies HER2 status in about 50% of initial HER2 FISH equivocal cases. In addition, HER2 equivocal cases merit further study as there is limited information about prognosis and optimal treatment strategy for this population.

Discordance of the estrogen receptor and HER-2/neu in breast cancer from primary lesion to first and second metastatic site

BACKGROUND

Hormone receptor and HER-2/neu discordance between the primary lesion and first metastasis has been reported. This study was performed to determine further biomarker discordance rates between the first and subsequent metastatic breast cancer lesions.

METHODS

We performed a retrospective review of paired biomarkers from primary breast cancers compared to first reported and subsequent metastases from 103 patients with breast cancer. The estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu status were reported at all three time points. In addition, hormone, cytotoxic, and targeted treatments were recorded for primary and metastatic disease, and survival was determined.

RESULTS

Between the primary and first metastases, discordance rates for ER, PR, and HER-2/neu were 15.8%, 33.7%, and 14.3%, respectively. There was discordance between the first and second metastases for the ER receptor in 18.8%, PR receptor in 19.8%, and HER-2/neu in 10.7%. Overall, there was discordance between the primary tumor and either the first or second metastases for ER in 27.7%, PR receptor in 40.7%, and HER-2/neu in 19.6% of cases. Discordance of either ER or PR affected survival, with worse survival experienced by those patients with all three hormone receptors remaining negative, and intermediate survival reported for those with discordant tumors (ER χ2=14.27, p=0.0008; PR χ2=11.31, p=0.0035). There was no difference in survival for patients whose HER-2/neu tumors were discordant.

CONCLUSION

This study demonstrated that continued metastatic disease evolution may be associated with different tumor biology and that studies of metastatic lesions appear warranted, especially if targeted therapy is an option.

Annexin A3 as a Prognostic Biomarker for Breast Cancer: A Retrospective Study

To validate the correlation between ANXA3 expression and prognosis in breast cancer, a retrospective study encompassing 309 breast cancer patients was performed. The expression of ANXA3 was determined by the immunohistochemical examination of tissue sections by the Max Vision™ method. The ANXA3 levels in the patient samples were validated for the prognosis based on age, menopause status, tumor size, tumor node, metastasis stage, the number of lymphatic metastases, oncology grade, and molecular subtyping. An elevated expression of ANXA3 was detected in breast cancer samples, compared to adjacent tissue samples, and significant correlation depending on the number of lymphatic metastases (P = 0.001) and histological grade (P = 0.004) was observed. The number of lymphatic metastases and ANXA3 expression were identified as independent risk factors affecting the disease-free survival and overall survival. Significantly (P < 0.002) higher level of ANXA3 was detected in triple-negative breast cancer compared to other subtypes. There was no significant (P > 0.05) change in the expression of ANXA3 with respect to age, menopausal status, tumor size, and clinical stage. The findings implicate the expression of ANXA3 with the natural progression of breast cancer and associate it with increased lymphatic metastasis. The study validates the use of ANXA3 as a potential prognosis biomarker for breast cancer.