Assessing the HER2 status in mucinous epithelial ovarian cancer on the basis of the 2013 ASCO/CAP guideline update

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

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

HER2-low and Overexpression in Mucinous Ovarian Cancer: Analysis of ASCO/CAP and ToGA Immunohistochemical Scoring

Mucinous ovarian carcinoma is an uncommon malignancy characterized by resistance to chemotherapy and poor survival in the metastatic setting. HER2 amplification is a frequent late event in carcinogenesis, yet the incidence of HER2-low in mucinous ovarian carcinoma is unknown. Further, the optimal method for determining overexpression in these tumors is not established. We sought to assess the ASCO/CAP and ToGA trial scoring methods for HER2 IHC with correlation to FISH, p53, and mismatch repair protein status and to determine the incidence of HER2-low in mucinous ovarian carcinoma. A total of 29 tumors from 23 patients were included. Immunohistochemistry for HER2, p53, MLH1, PMS2, MSH2, and MSH6 was performed. Scoring was performed according to the ASCO/CAP and ToGA trial criteria. HER2 FISH was performed and scored according to the ASCO/CAP criteria. The proportion of HER2-low, defined as 1+ or 2+ staining with negative FISH, was determined. Using ASCO/CAP, 26% demonstrated 3+ while 35% demonstrated 2+ staining. Using ToGA, 30% demonstrated 3+ while 57% demonstrated 2+ staining. By FISH, 26% were positive for HER2 amplification. Both systems captured all FISH-positive cases; the use of ASCO/CAP resulted in fewer equivocal and false-positive cases. Among HER2-negative cases, 88% were HER2-low. Aberrant p53 expression was detected in 55% of cases; mismatch repair deficiency was not identified in any cases. ASCO/CAP guidelines are accurate and resource-effective in determining HER2 overexpression in mucinous ovarian carcinoma. HER2-low is common in these tumors; further studies to determine the role of HER2-targeted therapy including antibody-drug conjugates are indicated.

The role of HER2 as a therapeutic biomarker in gynaecological malignancy: potential for use beyond uterine serous carcinoma

Human epidermal growth factor receptor 2 (HER2) is a prognostic biomarker and therapeutic target in carcinomas of the breast, stomach and colon. In 2018, clinical trial data confirmed the prognostic and predictive role of HER2 in uterine serous carcinoma, with a demonstrated survival benefit from combined chemotherapy and anti-HER2 targeted therapy in patients with advanced or recurrent disease. Approximately one-third of uterine serous carcinomas demonstrate HER2 protein overexpression and/or gene amplification and HER2 immunohistochemistry, supplemented by in situ hybridisation in equivocal cases, is fast becoming a reflex ancillary test at time of diagnosis. The potential role of HER2 in gynaecological tumours other than uterine serous carcinoma is yet to be firmly established. With the advent of personalised medicine, routine tumour sequencing and pursuit of targeted therapies, this is a field currently under active investigation. Emerging data suggest triaging endometrial carcinomas for HER2 analysis based on molecular classification may be superior to histotype-based testing, with copy-number high/p53 mutant tumours enriched for HER2 overexpression or amplification. Accordingly, many carcinosarcomas and a subset of clear cell and high-grade endometrioid carcinomas may be eligible for HER2 targeted therapy, although any clinical benefit in this context is currently undefined. For ovarian carcinomas, combined data support the role of HER2 as a prognostic biomarker, however its use as a therapeutic target is yet to be elucidated through clinical trials. In the cervix, reported rates of HER2 overexpression vary and are generally low, and currently there is insufficient evidence to justify routine HER2 testing in this context. Limited data suggest HER2 holds promise as a prognostic and predictive biomarker in vulvar Paget disease. Future clinical trials, with pathologist input to develop and refine site-specific scoring criteria, are required to establish what role HER2 might play more broadly in gynaecological cancer care.

High frequency of BRAF mutations in primary mucinous ovarian carcinoma of Taiwanese patients

OBJECTIVE

Considering the clinical evidence of BRAF inhibitors that can treat melanoma patients successfully, we aimed to investigate the status of BRAF mutations of primary mucinous ovarian carcinomas (MOC) in Taiwanese women, and apply the emerging paradigm classification of BRAF mutation groups.

MATERIALS AND METHODS

20 archived primary MOC samples were analyzed. The BRAF mutations of activation segment (exon 15), CR3 (conserved regions 3), kinase domain of the BRAF gene were analyzed using the highly sensitive BRAF mutant enriched kit (FemtoPath®) with Sanger sequencing method. Additionally, we extended our prior reported data of HER2 aberrations and KRAS mutation into this study in order to compare with the status of BRAF mutation.

RESULTS

Of them (n = 20), 16 (80%) harbored BRAF missense mutations. Their mutation profile and case number (n) were categorized as (1) class I: V600E (n=1), V600M (n = 1); (2) class II: A598V (n = 1), T599I (n = 10); (3) class III: none (n = 0); and (4) unclassified variants: S602F (n = 2), T599I/S602F (n = 1). The BRAF S602F is novel. The prevalence of BRAF mutation is significantly higher than either HER2 mutation (80% vs. 35%; p = 0.022) or HER2 amplification (80% vs. 35%; p = 0.022). However, the mutation rates of BRAF and KRAS were not significantly different (80% vs. 60%; p = 0.289).

CONCLUSION

Activating BRAF mutation, HER2 amplification, HER2 mutation and KRAS mutation were not mutually exclusive. However, they may even have a synergistic effect in tumorigenesis. BRAF mutation is not uncommon in primary MOC of Taiwanese. The BRAF mutant (T599I) stands the majority. We suggested that there was a lower potential response to the existing V600 BRAF inhibitors, but may be responsive to dual BRAF plus MEK inhibitors or single MEK inhibitor. Further studies are warranted to investigate the clinical benefits of newly targeted therapy in recurrent or advanced stage primary MOC patients carrying different classes of BRAF mutation.

The Protein Landscape of Mucinous Ovarian Cancer: Towards a Theranostic

MOC is a rare histotype of epithelial ovarian cancer, and current management options are inadequate for the treatment of late stage or recurrent disease. A shift towards personalised medicines in ovarian cancer is being observed, with trials targeting specific molecular pathways, however, MOC lags due to its rarity. Theranostics is a rapidly evolving category of personalised medicine, encompassing both a diagnostic and therapeutic approach by recognising targets that are expressed highly in tumour tissue in order to deliver a therapeutic payload. The present review evaluates the protein landscape of MOC in recent immunohistochemical- and proteomic-based research, aiming to identify potential candidates for theranostic application. Fourteen proteins were selected based on cell membrane localisation: HER2, EGFR, FOLR1, RAC1, GPR158, CEACAM6, MUC16, PD-L1, NHE1, CEACAM5, MUC1, ACE2, GP2, and PTPRH. Optimal proteins to target using theranostic agents must exhibit high membrane expression on cancerous tissue with low expression on healthy tissue to afford improved disease outcomes with minimal off-target effects and toxicities. We provide guidelines to consider in the selection of a theranostic target for MOC and suggest future directions in evaluating the results of this review.

The status of Her2 amplification and Kras mutations in mucinous ovarian carcinoma

Jayson GC et al. remarked in Lancet that nearly 100% of mucinous ovarian cancer cases have Kras mutation as well as a high frequency of Her2 amplification. Using the Abbott PathVysion Her2 DNA Probe Kit and Kras mutant-enriched PCR Kits (FemtoPath®), 21 samples of primary ovarian mucinous cystadenocarcinomas from Taiwanese patients were examined to determine the status of Her2 amplification and Kras mutations. Our results showed the Her2 amplification rates were 33.33%, while the Kras mutation rates were 61.90%. We present here our results in order to enlighten the readership that the ~100% Kras mutant frequency and the high Her2 amplification rate reported by Jayson et al. may be too exaggerated to be applicable into all populations. Additionally, we report another 2 novel Kras mutations (A11V, V14I).

Systematic assessment of HER2/neu in gynecologic neoplasms, an institutional experience

BACKGROUND

HER2/neu overexpression and/or amplification has been widely studied in a number of solid tumors, primarily in the breast. In gynecologic neoplasms, determination of HER2/neu status has not been well studied as a predictive biomarker in anti-HER2/neu treatment.

METHODS

We systematically evaluated the HER2/neu reactions by immunohistochemistry and fluorescent in situ hybridization in malignant gynecologic neoplasms as experienced in our institution.

RESULTS

The HER2/neu overexpression or amplification occurred in 8 % of the cancers of the gynecological organs in our series. Majority of the HER2/neu overexpression and/or amplification occurred in clear cell (27 %) and serous (11 %) carcinomas. HER2/neu positivity was also seen in undifferentiated as well as in mixed clear cell and serous carcinomas. Discordant IHC and FISH results (positive by FISH but not IHC) was seen in 2 cases. Majority of the HER2/neu overexpression and/or amplification occurs in the endometrium rather than the ovary. Heterogeneity of the HER2/neu by IHC staining was in < 2 % of the tumors in our series.

CONCLUSIONS

We recommend the HER2/neu studies on Müllerian carcinomas of clear cell, serous, and undifferentiated types, particularly when they arise in the endometrium. Since there are some discordant IHC/FISH results, we also propose performing the HER2/neu testing by FISH when the IHC score is less than 3 + .

Pattern of HER-2 Gene Amplification and Protein Expression in Benign, Borderline, and Malignant Ovarian Serous and Mucinous Neoplasms

Amplification of HER-2 gene and overexpression of HER-2 receptor play a significant role in the progression of a number of malignancies such as breast cancer. Trastuzumab (anti-HER-2 therapeutic agent) has been used successfully in treatment of breast cancer. The aim of this study was to assess the pattern of HER-2 gene amplification and of HER-2 receptor expression in a spectrum of serous and mucinous ovarian tumors to determine whether HER-2 is altered in these neoplasms similar to that occurring in breast cancer. Formalin-fixed paraffin-embedded microarray tissue sections from 212 specimens were stained with HER-2 antibody using immunohistochemistry and with anti-HER-2 DNA probe using chromogenic in situ hybridization. Specimens consisted of 65 benign tumors (50 serous and 15 mucinous), 26 borderline (13 serous and 13 mucinous), 73 malignant tumors (53 serous carcinoma and 20 mucinous carcinoma), 18 metastatic deposits (13 serous and 5 mucinous), in addition to 30 normal tissues (16 ovarian surface and 14 normal fallopian tube). HER-2 protein-positive expression was not detected in the normal or the benign tissues. Borderline neoplasms showed positive staining, but no overexpression. HER-2 overexpression was seen only in 4 carcinoma specimens: 1/53 (1.8%) primary serous carcinomas and 3/20 (15%) primary mucinous carcinomas. HER-2 gene amplification was seen in 4 specimens: 2 primary mucinous carcinomas and 2 malignant deposits of these 2 mucinous carcinomas. In conclusion, alteration of HER-2 was not detected in ovarian serous neoplasms; however, in mucinous carcinoma, HER-2 amplification and overexpression occur.

CEP3 and CEP17 DNA probe potential in the genetic diagnosis and prognostic prediction of esophageal squamous cell cancer

The aim of the present study was to investigate the clinical application of molecular pathological diagnosis for the prognosis of Kazakh patients with esophageal squamous cell carcinoma (ESCC) using centromere enumeration probes (CEPs) for chromosomes 3 and 17. A total of 40 patients with ESCC that had received radical surgical treatment and 10 healthy control participants were enrolled in the present study. Touch preparations of fresh cancerous and normal tissues were completed and fluorescence in situ hybridization (FISH) was performed to count the copy numbers of CEP 3 and 17, and abnormalities were analyzed, in comparison with routine pathological diagnoses. FISH analysis demonstrated that abnormal copy numbers of CEP 3 and 17 (aneuploidy) were detected in all 40 patients with ESCC. CEP 3 and 17 polyploidy rates differed significantly between poorly differentiated, moderately differentiated and well-differentiated ESCC groups (P<0.05): Well-differentiated, 35.38 and 30.92%; moderately differentiated, 55.81 and 44.43%; and poorly differentiated, 76.26 and 71.90%, respectively. Furthermore, polyploidy rates were significantly increased in the group with lymph node metastasis, as compared with the group without (CEP 3, P=0.0001; CEP 17, P=0.012). Variations in the copy numbers of CEP 3 and 17 were demonstrated to be correlated with the level of differentiation and lymph node metastasis in patients with ESCC. Therefore, the present results indicate that DNA probes may be used to predict prognostic factors in patients with ESCC. Furthermore, FISH technology is an objective and qualitative method that is capable of detecting variations in CEP 3 and 17; therefore, FISH may be used in the genetic diagnosis of ESCC in Kazakh patients.

Assessment of HER2 Status Using Immunohistochemistry (IHC) and Fluorescence In Situ Hybridization (FISH) Techniques in Mucinous Epithelial Ovarian Cancer: A Comprehensive Comparison between ToGA Biopsy Method and ToGA Surgical Specimen Method

We aimed to compare the assay performance characteristics of HER2 status in mucinous epithelial ovarian cancer (EOC) by ToGA (Trastuzumab for Gastric Cancer) biopsy versus ToGA surgical specimen methods. Forty-nine tissue microarray (TMA) samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using ToGA trial HER2 scoring methods. The overall concordance between IHC and FISH by the ToGA surgical specimen method is 97.56% and by the ToGA biopsy specimen method is 97.14%. The agreements of HER2 IHC results under both biopsy and surgical specimen methods were nearly perfect (weighted kappa = 0.845). Additionally, the percentage of Her2 FISH amplification showed increasing trend with increasing HER2 IHC ordinals (negative, equivocal, positive) by both TOGA biopsy (P<0.001) and surgical specimen method (P<0.001). After excluding equivocal cases, the sensitivity (100%), PPV (88.89%) and NPV (100%) of HER2 IHC were unchanged under either surgical specimen method or biopsy method. However, the specificity (96.97%) and accuracy (97.56%) of HER2 IHC was slightly higher under the surgical specimen method than those (specificity 96.30%, accuracy 97.14%) under the biopsy method. Of the total 49 cases, the number (n = 14) of HER2 IHC equivocal results under the ToGA biopsy method was 1.75-fold higher than those (n = 8) under the ToGA surgical specimen method (28.57% vs. 16.32%). Therefore, compared to ToGA surgery specimen method, the ToGA biopsy method caused more equivocal IHC cases to be referred to FISH testing and did not increase the detection rates of Her2 FISH amplification.

Synthesis, characterization and targeting chemotherapy for ovarian cancer of trastuzumab-SN-38 conjugates

Antibody-drug conjugates (ADCs), combining monoclonal antibody with high cytotoxicity chemotherapeutic drug (warhead), have been successfully applied for clinical cancer therapy. Linker technology to select and design linker connecting warhead with antibody, is critical to the success of therapeutic ADCs. In this study, three kinds of linkers were designed to connect SN-38, the bioactive metabolite of the anticancer drug irinotecan (CPT-11), which is 100-1000 times more potent than CPT-11, with the anti-HER2 antibody trastuzumab to prepare three different ADC conjugates (T-SN38 A, B and C). Meanwhile, we compared the anti-ovarian cancer effect of these three T-SN38 conjugates with trastuzumab in vitro and in vivo. Our in vitro results showed that T-SN38 A, B and C (drug-to-antibody ratio, DAR=3.7, 3.2, 3.4) were 2 to 3 times as cytotoxic as SN-38, and the IC50 for these three conjugates on SKOV-3 cell line at 72 h were 5.2 ± 0.3, 4.4 ± 0.7, and 5.1 ± 0.4 nM respectively. In our in vivo studies, T-SN38 conjugates had well targeting ability for tumor tissue and all three of them had much higher anti-ovarian cancer potency than trastuzumab. Among of them, T-SN38 B, which coupled SN-38 with trastuzumab by a carbonate bond, has the best anti-ovarian cancer potency. In conclusion, the novel HER2-targeting ADCs T-SN38 have great potential for HER2-positive ovarian cancer. Moreover, the SN-38-Linkers designed in this study can also be used to connect with other antibodies for the therapy of other cancers.

A qualitative study comparing the assay performance characteristics between the 2007 and the 2013 American Society for Clinical Oncology and College of American Pathologists HER2 scoring methods in mucinous epithelial ovarian cancer

The remarkable success of trastuzumab and other newly developed anti-HER2 (human epidermal growth factor receptor 2) therapies in breast, gastric, or gastroesophageal junction cancer patients has supported us to investigate the HER2 status and its possible therapeutic implication in mucinous epithelial ovarian cancer (EOC). However, there is currently no standardization of HER2 scoring criteria in mucinous EOC. In this study, we aimed to compare both the assay performance characteristics of the 2007 and the 2013 American Society for Clinical Oncology and College of American Pathologists scoring methods. Forty-nine tissue microarray samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using the 2007 and the 2013 criteria, respectively. The overall concordance between IHC and FISH by the 2007 criteria was 97.92 % (kappa = 0.921), and that by the 2013 criteria was 100% (kappa = 1.000). The percentage of Her2 FISH-amplified cases showed an increasing trend significantly through their corresponding HER2 IHC ordinals by the 2007 and the 2013 criteria, respectively (P < 0.001, P < 0.001). After excluding equivocal cases, the specificity (100%) and positive predictive value (100%) were unchanged under either the 2007 or the 2013 criteria. The sensitivity (100%), negative predictive value (NPV) (100%), and accuracy (100%) of HER2 IHC were higher under the 2013 criteria than those (sensitivity 87.5%, NPV 97.6%, and accuracy 97.9%) under the 2007 criteria. Of the total 49 cases, the number (n = 4) of HER2 IHC equivocal results under the 2013 criteria was 4-fold higher than that (n = 1) under the 2007 criteria (8.16% vs 2.04%). Conclusively, if first tested by IHC, the 2013 criteria caused more equivocal HER2 IHC cases to be referred to Her2 FISH testing than the 2007 criteria. That decreased the false-negative rate of HER2 status and increased the detection rates of HER2 positivity in mucinous EOC.