Immunohistochemistry in gynecologic carcinomas: Practical update with diagnostic and clinical considerations based on the 2020 WHO classification of tumors

Performance of HER2 DAKO HercepTest and Ventana 4B5 immunohistochemical assays on detecting HER2 gene-amplification in uterine serous carcinomas

We compared the performance of two commonly-used HER2 immunohistochemistry (IHC) assays in uterine serous carcinomas (USC), correlating with HER2 gene amplification by fluorescence in-situ hybridization (FISH). Sixty-five USCs were stained by both HercepTest™ and PATHWAY 4B5 assays. FISH was performed by HER2 IQFISH pharmDx. Consensus HER2 IHC scoring was performed, and HER2 testing results were evaluated using USC-specific criteria. Complete concordance between HercepTest and 4B5 assays was achieved in 44/65 tumors (68%). The overall HER2 IHC/FISH concordance was 94% (45/48) by HercepTest and 91% (42/46) by 4B5. All HER2 IHC 3+ cases with HercepTest (n = 6) and 4B5 (n = 4) were gene-amplified, corresponding to specificities of 100%. For cases with IHC 2+, 41% (7/17) by HercepTest and 42% (8/19) by 4B5 had HER2 gene amplification. The sensitivity for HercepTest and 4B5 were 38% and 25%, respectively, at a cut-off of IHC 3+ (P = 0.50), and were 81% and 75%, respectively, at a cut-off of IHC 2+ (P > 0.99). Among HER2 IHC 0-1+ cases, 3/42 cases by HercepTest and 4/42 cases by 4B5 showed amplified FISH results, corresponding to overall false negative rates of 19% for HercepTest and 25% for 4B5. By using USC-specific IHC scoring criteria, both HercepTest and 4B5 assays showed high specificities (100%) for HER2 gene amplification in IHC 3+ cases, high IHC/FISH concordance, and comparable sensitivity for detecting HER2 gene amplification. The notable false negative rates using IHC 2+ as a cut-off for reflexing FISH analysis may warrant consideration for performing FISH in IHC 1+ cases until more data become available.

Practical Updates and Diagnostic Challenges in Endometrial Carcinoma

CONTEXT.—

Clinical management of endometrial carcinoma largely depends on the morphologic parameters ascertained based on the pathologic evaluation of surgical resection specimens. However, there are numerous controversial and nonstandardized aspects of both the macroscopic and microscopic assessment of surgical specimens, including grossing, adequate sampling, diagnosis, staging, reporting, and ancillary testing.

OBJECTIVE.—

To provide a comprehensive practical review of standardized grossing, key morphologic findings for reporting and staging, and diagnostic and prognostic use of ancillary testing in endometrial carcinomas.

DATA SOURCES.—

The existing literature, recommendations of the International Society of Gynecological Pathologists, and specialty consensus guidelines.

CONCLUSIONS.—

This review article summarizes important aspects of the grossing and sampling of surgical resection specimens for microscopic examination, key morphologic parameters that are required for reporting and staging, and morphologic features and immunoprofiles helpful in the differential diagnosis of low-grade and high-grade endometrial carcinomas, as well as the current status of the molecular classification of endometrial carcinoma and human epidermal growth factor receptor 2 testing in serous carcinoma. The information presented herein can be helpful in overcoming diagnostic challenges and issues related to the pathology reporting of endometrial carcinoma to practicing anatomic pathologists.

Correlative Assessment of p53 Immunostaining Patterns and TP53 Mutation Status by Next-Generation Sequencing in High-Grade Endometrial Carcinomas

TP53 mutations are frequently identified in the copy number-high molecular subgroup of endometrial carcinomas (ECs). P53 immunohistochemistry (IHC) is a widely used surrogate marker reflecting the mutational status of TP53 , and recent reports have shown ~95% concordance between the two methods in ECs. While these results are promising, studies evaluating the correlation between different p53 IHC staining patterns and comprehensive next-generation sequencing results are still limited. We compared the p53 IHC staining patterns, scored as wild-type, diffuse nuclear overexpression, null/complete absence, and cytoplasmic, to next-generation sequencing results reported by FoundationOneCDx in 43 high-grade ECs: 20 serous ECs, 9 mixed ECs with a serous component, 4 carcinosarcomas with a serous component, and 10 grade 3 endometrioid ECs. The concordance of p53 IHC and TP53 mutation status was 100% (43/43) overall, including 100% (33/33) concordance in tumors with a serous component and 100% (10/10) in endometrioid ECs. Among the 35 tumors with aberrant p53 expression the most commonly observed pattern was diffuse nuclear overexpression seen in 69% (24/35), followed by cytoplasmic staining in 17% (6/35), and complete absence of staining (null) in 14% (5/35) of tumors. Of the 6 tumors with cytoplasmic staining, 4 corresponded to missense mutations within the DNA binding domain (V157F in 2 tumors, and S127P and R280S, in 2 tumor each), while 2 corresponded to nonsense mutations in the tetramerization domain (p.E339*). Our results further support that p53 IHC can serve as an accurate predictor of TP53 alterations in ECs to aid the molecular-based tumor classification and the distinction between tumor histotypes, both of which play an important role in the assessment of clinical prognosis and therapeutic decision making. In addition, our data suggest, that the type and position of TP53 mutation may not directly correlate with the observed p53 IHC pattern in all tumors, and that there may be alternative mechanisms for cytoplasmic localization (other than mutations involving the nuclear localization domain), possibly due to conformational changes or posttranslational modifications of the aberrant p53 protein.

Budget impact analysis of molecular subtype profiling in endometrial cancer

OBJECTIVE

This study evaluated the costs associated with four approaches to classifying endometrial cancer (EC), including histomorphological, histomorphological with ancillary immunohistochemical assays, histomolecular and selective molecular classification.

METHODS

Direct costs were determined per EC sample from the hospital's perspective. A budget impact analysis and sensitivity analysis were conducted to estimate the mean, minimum and maximum costs per sample and annual institutional costs in adjusted 2022 Canadian dollars. A provincial cost forecast was projected based on expected 2022 EC biopsies.

RESULTS

In 2018, our institution performed 190 EC biopsies. The mean cost per biopsy was $158 ($156-$212) for histomorphological classification, $384 ($360-$514) for histomorphological classification with immunohistochemistry and $1297 ($1265-1833) for histomolecular classification. Total annual institutional cost for histomorphological classification was $29,980 and $72,950 with immunohistochemistry. For histomolecular classification, the first year cost was $246,521, accounting for initial educational learning curve, and $233,461 thereafter, assuming a consistent number of biopsies per year. Targeted implementation of histomolecular classification among high-grade, p53 abnormal and/or MMR-deficient ECs (56% of cases) cost $169,688 in the first year and $162,418 annually thereafter. With a projected 3400 EC biopsies in Ontario in 2022, histomorphological classification would annually cost $537,078 and $1,305,677 with immunohistochemistry. Histomolecular classification would cost $4,410,203 in the first year and $4,176,737 annually once established. Selective molecular classification would lead to a cost of $3,044,178 in the first year and $2,913,443 thereafter.

CONCLUSIONS

The study highlights the need for informed decision-making when implementing molecular classification in clinical practice, given the substantial incremental healthcare costs associated with these approaches.

Molecular pathology and clinical treatment of independent HPV primary serous carcinoma of the uterine cervix (USCC): A case report

On October 23, 2020, a 69-year-old Chinese female patient was admitted to Yuncheng Hospital due to a history of postmenopausal bleeding and lower abdominal pain for 5 months. The HPV test and pathology results indicated the presence of independent HPV in primary serous carcinoma of the uterine cervix. The genetic testing identified variants of uncertain significance (PAX8 p.Tyr 410 Ter and TP53 p.Asn 247 Ile), microsatellite instability stable (MSI-S), tumor mutational burden (TMB) 7.33Muts/Mb, and an elevated tumor neoantigen burden. Before undergoing radical hysterectomy treatment, the patient exhibited a positive response to three cycles of intravenous docetaxel (100 mg/3 h) and carboplatin (450 mg/1 h). Following the surgery, she received an additional three cycles of docetaxel (100 mg/3 h) and carboplatin (500 mg/1 h), accompanied by 25 cycles of radiation therapy (DT 46Gy/2Gy/23f). Concurrently, cisplatin (450 mg/1 h) was administered. As of now, the patient has achieved 20 months of disease-free survival.

Androgen receptor amplification in mesonephric remnants

Mesonephric remnants (MRs) are embryonic vestiges most commonly found in female pathology specimens from the lateral wall of the cervix. The highly regulated genetic programme of mesonephric duct development has been well characterised in animals based on traditional surgical castration and knockout mouse experiments. However, the process is incompletely understood in humans. MRs are believed to give rise to mesonephric neoplasms, which are rare tumours with uncertain pathophysiology. There is a dearth of molecular studies on mesonephric neoplasms in part due to their rarity. Here, we report the results of next-generation sequencing of MR, which identified amplification of the androgen receptor gene for the first time to the best of our knowledge and discuss the potential implications in the context of the literature.

Determination of the Cancer Genome Atlas (TCGA) Endometrial Cancer Molecular Subtypes Using the Variant Interpretation and Clinical Decision Support Software MH Guide

BACKGROUND

The Cancer Genome Atlas (TCGA) network (United States National Cancer Institute) identified four molecular endometrial cancer (EC) subtypes using an extensive multi-method approach. The aim of this study was to determine the four TCGA EC molecular subtypes using a single-method whole-exome sequencing (WES)-based approach provided by MH Guide (Molecular Health, Heidelberg, Germany).

METHODS

WES and clinical data of n = 232 EC patients were obtained from TCGA. The four TCGA EC molecular subtypes designated as (i) Mutated Polymerase ε (POLE), (ii) Microsatellite Instability (MSI), (iii) Copy Number (CN) low and, (iv) CN-high were determined using the MH Guide software. The prognostic value of the subtypes determined by MH Guide were compared with the TCGA classification.

RESULTS

Analysis of WES data using the MH Guide software led to the precise identification of the four EC molecular subtypes analogous to the TCGA classification. Both approaches displayed high concordance in terms of prognostic significance.

CONCLUSIONS

The multi-method-based TCGA EC molecular subtypes can reliably be reproduced by the single-method-based MH Guide approach. The easy-to-implement single-method MH Guide approach represents a promising diagnostic tool.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with endometrial cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with endometrial cancer was published in 2022. It was therefore decided, by both the ESMO and the Indian Society of Medical and Paediatric Oncology (ISMPO), to convene a virtual meeting in July 2022 to adapt the ESMO 2022 guidelines to take into account the variations in the management of endometrial cancer in Asia. These guidelines represent the consensus opinion of a panel of Asian experts representing the oncological societies of China (CSCO), India (ISMPO), Indonesia (ISHMO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO). Voting was based on scientific evidence and was conducted independently of the current treatment practices and treatment access constraints in the different Asian countries, which were discussed when appropriate. The aim of this guideline manuscript is to provide guidance for the optimisation and harmonisation of the management of patients with endometrial cancer across the different regions of Asia, drawing on the evidence provided by Western and Asian trials whilst respecting the variations in clinical presentation, diagnostic practices including molecular profiling and disparities in access to therapeutic options, including drug approvals and reimbursement strategies.

Comprehensive Approach to Genomic and Immune Profiling: Insights of a Real-World Experience in Gynecological Tumors

Gynecological cancer accounts for an elevated incidence worldwide requiring responsiveness regarding its care. The comprehensive genomic approach agrees with the classification of certain tumor types. We evaluated 49 patients with gynecological tumors undergoing high-throughput sequencing to explore whether identifying alterations in cancer-associated genes could characterize concrete histological subtypes. We performed immune examination and analyzed subsequent clinical impact. We found 220 genomic aberrations mostly distributed as single nucleotide variants (SNV, 77%). Only 3% were classified as variants of strong clinical significance in BRCA1 and BRCA2 of ovarian high-grade serous (HGSC) and uterine endometrioid carcinoma. TP53 and BRCA1 occurred in 72% and 28% of HGSC. Cervical squamous cell carcinoma was entirely HPV-associated and mutations occurred in PIK3CA (60%), as well as in uterine serous carcinoma (80%). Alterations were seen in PTEN (71%) and PIK3CA (60%) of uterine endometrioid carcinoma. Elevated programmed death-ligand 1 (PD-L1) was associated with high TILs. Either PD-L1 augmented in deficient mis-matched repair (MMR) proteins or POLE mutated cases when compared to a proficient MMR state. An 18% received genotype-guided therapy and a 4% immunotherapy. The description of tumor subtypes is plausible through high-throughput sequencing by recognizing clinically relevant alterations. Additional concomitant assessment of immune biomarkers identifies candidates for immunotherapy.