Clinicopathologic and Genomic Analysis of TP53-Mutated Endometrial Carcinomas

Particles and Prejudice: Nanomedicine Approaches to Reducing Health Disparities in Endometrial Cancer

Endometrial cancer is the most common gynecological malignancy worldwide and unfortunately has a much higher mortality rate in Black women compared with White women. Many potential factors contribute to these mortality rates, including the underlying effects of systemic and interpersonal racism. Furthermore, other trends in medicine have potential links to these rates including participation in clinical trials, hormone therapy, and pre-existing health conditions. Addressing the high incidence and disparate mortality rates in endometrial cancer requires novel methods, such as nanoparticle-based therapeutics. These therapeutics have been growing in increasing prevalence in pre-clinical development and have far-reaching implications in cancer therapy. The rigor of pre-clinical studies is enhanced by the likeness of the model to the human body. In systems for 3D cell culture, for example, the extracellular matrix mimics the tumor more closely. The increasing emphasis on precision medicine can be applied to cancer using nanoparticle-based methods and applied to pre-clinical models by using patient-derived model data. This review highlights the intersections of nanomedicine, precision medicine, and racial disparities within endometrial cancer and provides insights into reducing health disparities using recent scientific advances on the nanoscale.

Concurrent POLE hotspot mutations and mismatch repair deficiency/microsatellite instability in endometrial cancer: A challenge in molecular classification

OBJECTIVE

Endometrial carcinoma (EC) has different molecular subtypes associated with varied prognosis. We sought to characterize the molecular features of ECs with POLE hotspot mutations and concurrent mismatch repair (MMR) deficiency/high microsatellite instability (MSI).

METHODS

We identified POLE-mutated (POLEmut), MMR-deficient (MMRd)/MSI-high (MSI-H), or combined POLEmut/MMRd ECs subjected to clinical tumor-normal panel sequencing between 2014 and 2023. Clonality of somatic mutations, MSI scoring, tumor mutational burden (TMB), proportion of somatic insertions and deletions (indels), and single base substitution (SBS) mutational signatures were extracted.

RESULTS

We identified 41 ECs harboring POLE exonuclease domain hotspot mutations, 138 MMRd and/or MSI-H ECs, and 14 POLEmut/MMRd ECs. Among the 14 POLEmut/MMRd ECs, 11 (79 %) exhibited clonal POLE hotspot mutations; 4 (29 %) had a dominant POLE-related mutational signature, 4 (29 %) displayed dominant MMRd-related signatures, and 6 (43 %) had mixtures of POLE, aging/clock, MMRd, and POLEmut/MMRd-related SBS mutational signatures. The number of single nucleotide variants was higher in POLEmut/MMR-proficient (MMRp) and in POLEmut/MMRd ECs compared to POLE wild-type (wt)/MMRd EC (both p < 0.001). Small indels were enriched in POLEwt/MMRd ECs (p < 0.001). TMB was highest in POLEmut/MMRd EC compared to POLEmut/MMRp and POLEwt/MMRd ECs (both p < 0.001). Of 14 patients with POLEmut/MMRd EC, 21 % had a recurrence, versus 10 % of those with POLEmut/MMRp EC. Similar findings were noted in 3 POLEmut ECs in patients with Lynch syndrome; akin to somatic POLEmut ECs, these tumors had high TMB.

CONCLUSION

POLEmut/MMRd ECs may be genetically distinct. Further studies are needed to assess the impact on outcomes and treatment response within this population.

p53 Abnormal (Copy Number High) Endometrioid Endometrial Carcinoma Has a Prognosis Indistinguishable From Serous Carcinoma

Among the 4 molecular subgroups of endometrial carcinoma, the p53 abnormal (copy number high) subgroup has the worst prognosis; however, the histologic characteristics of this subgroup are not well established. Also, it is not well established whether low-grade tumors can belong to the p53 abnormal molecular subgroup and if so, what is the prognostic significance of the p53-mutated molecular subgroup in low-grade tumors. In the current study, we included 146 p53-mutated endometrial carcinomas and performed molecular subgrouping either based on a combination of immunohistochemical studies for p53 and MMR protein expression and POLE mutation testing (81 cases) or based on array-based and sequencing-based technologies (65 cases). We excluded cases that belonged to the POLE mutant or MSI molecular subgroups and only studied p53 abnormal (molecular subgroup) endometrial carcinomas (125 cases). In 71 cases, the molecular subgroup was determined by a combination of immunohistochemical studies and POLE mutation testing, and in 54 cases by array-based and sequencing-based methods. We reviewed 1 to 2 representative digital slides from each case and recorded the morphologic characteristics as well as clinical, treatment, and survival follow-up data. Overall, 47 cases were classified as endometrioid carcinoma, 55 serous carcinoma, and 23 other histotypes. Eight cases were FIGO 1, 21 were FIGO 2, and 91 were FIGO 3. A significant proportion of the cases (24.2%) were histologically classified as low-grade (FIGO 1 or 2) endometrioid carcinoma. There was no morphologic characteristic that showed prognostic implication. There was no significant difference in survival among different histotypes (P=0.60). There was no significant difference in survival among low-grade endometrioid (FIGO 1 or 2) versus high-grade (FIGO 3) tumors (P=0.98). Early-stage (stage I), low-grade tumors showed no significant survival advantage over early-stage, high-grade tumors (P=0.16) and this was more evident in FIGO 2 tumors. Although not statistically significant, the FIGO 2 tumors showed a trend toward worse survival than FIGO 3 tumors. Among the cases with available treatment data, more patients with early-stage high-grade tumors received adjuvant treatment, compared to patients with early-stage low-grade tumors, possibly explaining this trend (P=0.03). In conclusion, the findings of our study suggest that low-grade p53 abnormal endometrioid endometrial carcinomas (especially FIGO 2 tumors) have an aggressive course, with a prognosis similar to high-grade tumors. Furthermore, our study suggests that patients who had early-stage low-grade p53 abnormal disease might have been undertreated because of the "low-grade" histotype.

Copy number variations in endometrial cancer: from biological significance to clinical utility

The molecular basis of endometrial cancer, which is the most common malignancy of the female reproductive organs, relies not only on onset of mutations but also on copy number variations, the latter consisting of gene gains or losses. In this review, we introduce copy number variations and discuss their involvement in endometrial cancer to determine the perspectives of clinical applicability. We performed a literature analysis on PubMed of publications over the past 30 years and annotated clinical information, including histological and molecular subtypes, adopted molecular techniques for identification of copy number variations, their locations, and the genes involved. We highlight correlations between the presence of some specific copy number variations and myometrial invasion, lymph node metastasis, advanced International Federation of Gynecology and Obstetrics (FIGO) stage, high grade, drug response, and cancer progression. In particular, type I endometrial cancer cells have few copy number variations and are mainly located in 8q and 1q, while type II, high grade, and advanced FIGO stage endometrial cancer cells are aneuploid and have a greater number of copy number variations. As expected, the higher the number of copy number variations the worse the prognosis, especially if they amplify CCNE1, ERBB2, KRAS, MYC, and PIK3CA oncogenes. Great variability in copy number and location among patients with the same endometrial cancer histological or molecular subtype emerged, making them interesting candidates to be explored for the improvement of patient stratification. Copy number variations have a role in endometrial cancer progression, and therefore their detection may be useful for more accurate prediction of prognosis. Unfortunately, only a few studies have been carried out on the role of copy number variations according to the molecular classification of endometrial cancer, and even fewer have explored the correlation with drugs. For these reasons, further studies, also using single cell RNA sequencing, are needed before reaching a clinical application.

Body mass index and adiposity influence responses to immune checkpoint inhibition in endometrial cancer

BACKGROUNDObesity is the foremost risk factor in the development of endometrial cancer (EC). However, the impact of obesity on the response to immune checkpoint inhibitors (ICI) in EC remains poorly understood. This retrospective study investigates the association among BMI, body fat distribution, and clinical and molecular characteristics of EC patients treated with ICI.METHODSWe analyzed progression-free survival (PFS) and overall survival (OS) in EC patients treated with ICI, categorized by BMI, fat-mass distribution, and molecular subtypes. Incidence of immune-related adverse events (irAEs) after ICI was also assessed based on BMI status.RESULTS524 EC patients were included in the study. Overweight and obese patients exhibited a significantly prolonged PFS and OS compared with normal BMI patients after treatment with ICI. Multivariable Cox's regression analysis confirmed the independent association of overweight and obesity with improved PFS and OS. Elevated visceral adipose tissue (VAT) was identified as a strong independent predictor for improved PFS to ICI. Associations between obesity and OS/PFS were particularly significant in the copy number-high/TP53abnormal (CN-H/TP53abn) EC molecular subtype. Finally, obese patients demonstrated a higher irAE rate compared with normal BMI individuals.CONCLUSIONObesity is associated with improved outcomes to ICI in EC patients and a higher rate of irAEs. This association is more pronounced in the CN-H/TP53abn EC molecular subtype.FUNDINGNIH/NCI Cancer Center; MSK Gerstner Physician Scholars Program; National Center for Advancing Translational Sciences (NCATS); Cycle for Survival; Breast Cancer Research Foundation.

Body mass index and adiposity influence responses to immune checkpoint inhibition in endometrial cancer

Background

Obesity is the foremost risk factor in the development of endometrial cancer (EC). However, the impact of obesity on the response to immune checkpoint inhibitors (ICI) in EC remains poorly understood. This retrospective study investigates the association between body mass index (BMI), body fat distribution, and clinical and molecular characteristics of EC patients treated with ICI.

Methods

We analyzed progression-free survival (PFS) and overall survival (OS) in EC patients treated with ICI, categorized by BMI, fat mass distribution, and molecular subtypes. Incidence of immune-related adverse events (irAE) after ICI was also assessed based on BMI status.

Results

524 EC patients were included in the study. Overweight and obese patients exhibited a significantly prolonged PFS and OS compared to normal BMI patients after treatment with ICI. Multivariable Cox regression analysis confirmed the independent association of overweight and obesity with improved PFS and OS. Elevated visceral adipose tissue (VAT) was identified as a strong independent predictor for improved PFS to ICI. Associations between obesity and OS/PFS were particularly significant in the copy number-high/TP53abnormal (CN-H/TP53abn) EC molecular subtype. Finally, obese patients demonstrated a higher irAE rate compared to normal BMI individuals.

Conclusion

Obesity is associated with improved outcomes to ICI in EC patients and a higher rate of irAEs. This association is more pronounced in the CN-H/TP53abn EC molecular subtype.

Funding

NIH/NCI Cancer Center Support Grant P30CA008748 (MSK). K08CA266740 and MSK Gerstner Physician Scholars Program (J.C.O). RUCCTS Grant #UL1 TR001866 (N.G-B and C.S.J). Cycle for survival and Breast Cancer Research Foundation grants (B.W).

Value of Molecular Typing Combined with Integrated Positron Emission Tomography/Magnetic Resonance Imaging in Risk Stratification of Endometrial Cancer

Objective

In this study, we investigated the value of molecular typing combined with integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) semi-quantitative indices in endometrial cancer risk stratification.

Methods

A retrospective study was conducted on 86 patients who were pathologically diagnosed with endometrial cancer and underwent surgical treatment after curettage at the Department of Obstetrics and Gynecology, Xuanwu Hospital, Capital Medical University between January 2017 and March 2023. Prior to surgery, each patient underwent integrated PET/MRI examination. The postoperative samples were subjected to pathological diagnosis, immunohistochemistry, and POLE gene sequencing. The differences in clinicopathological features between the four molecular subtypes and the differences in integrated PET/MRI semi-quantitative indexes (SUV max, ADC min) between the four molecular subtypes were analyzed. The cutoff value of molecular typing combined with integrated PET/MRI semi-quantitative indices for endometrial cancer risk stratification was determined.

Results

There were statistically significant differences in pathological types and tumor grades among the four molecular subtypes of endometrial cancer. The values of the four integrated PET/MRI semi-quantitative indices (SUV max and ADC min) of the molecular subtypes were statistically different. The SUV max was greater in the p53abn mutation group than in the POLE mutation group (P < 0.05). The ADC minimum of the POLE mutation group and the MMR-d group was lower than the NSMP group (P < 0.05). Molecular typing combined with the integrated PET/MRI semi-quantitative SUV max index can predict the low/medium risk group of endometrial cancer and the medium-high/high risk group, and the cut-off value of SUV max for predicting the risk of early endometrial cancer was 14.72 (sensitivity 66.7%, specificity 68.7%).

Conclusion

Molecular typing combined with integrated PET/MRI semi-quantitative indicators is useful to achieve risk stratification in patients diagnosed with endometrial cancer and guide individualized treatment.

Molecular and pathologic data to guide selection of patients with endometrioid endometrial cancer for ovarian preservation

OBJECTIVES

To investigate the association of molecular and pathologic factors with concurrent or recurrent ovarian disease to guide ovarian preservation in endometrioid endometrial cancer.

METHODS

Patients with endometrial cancer ≤50 years of age at diagnosis were grouped by elective oophorectomy versus ovarian preservation at staging (January 2010 to June 2021). Tumors were stratified by molecular sub-type and CTNNB1 mutational status with next generation sequencing and immunohistochemistry. Germline data identified patients with Lynch syndrome. Associations between molecular/pathologic features and concurrent ovarian disease in patients electing oophorectomy were compared with the Wilcoxon rank-sum and Fisher's exact tests. Associations with isolated ovarian recurrences in patients who chose ovarian preservation were examined using survival analyses.

RESULTS

Among 317 patients with endometrial cancer who underwent bilateral oophorectomy, 27 (9%) had malignant ovarian tumors, of whom 11 (41%) had no gross ovarian involvement on intra-operative survey. For patients with sequencing, concurrent malignant ovarian tumors were diagnosed in 0/14 (0%) POLE, 2/48 (4%) copy number-low/no specific molecular profile, 10/22 (45%) microsatellite instability-high, and 3/6 (50%) copy number-high/TP53abnormal patients (p<0.001). Concurrent malignant ovarian tumors were present in 1/30 (3%) hotspot CTNNB1-mutated versus 10/60 (17%) wildtype/CTNNB1 non-hotspot mutated endometrial cancer patients (p=0.11) and 7/28 (25%) Lynch versus 7/74 (9%) non-Lynch syndrome patients (p=0.06). Concurrent malignant ovarian tumors were present in patients with higher grade endometrial cancer (5% grade 1 vs 20% grade 2 and 24% grade 3; p<0.001), present versus absent lymphovascular space invasion (20% vs 6%; p=0.004), positive versus negative pelvic washings (28% vs 7%; p=0.016), and ≥50% versus <50% myoinvasion (24% vs 7%; p=0.004). Of 103 patients who chose ovarian preservation, four had isolated ovarian recurrences (two had high-risk pathologic features and two had high-risk molecular features).

CONCLUSIONS

The integration of molecular and pathologic data may improve risk stratification of pre-menopausal patients with endometrial cancer and enhance candidate selection for ovarian preservation.

The comparison of pure uterine serous carcinoma and mixed tumor with serous component: a single-institution review of 91 cases

BACKGROUND

Pure uterine serous carcinoma (p-USC) and mixed tumors with serous component (m-USC) are aggressive subtypes of endometrial cancer associated with high mortality rates. This retrospective study aimed to compare clinicopathologic features and outcomes of p-USC and m-USC in a single center.

METHODS

This study retrospectively reviewed patients diagnosed with USC at Peking University People's Hospital between 2008 and 2022. T-tests and chi-square tests were used to compare clinicopathological characteristics between p-USC and m-USC. Kaplan-Meier survival curve and Cox regression analysis were used to analyze the impact of clinical and pathological variables on OS and PFS.

RESULTS

Among the 91 patients who underwent surgery, 65.9% (n = 60) were p-USC, and 34.1% (n = 31) were m-USC. Patients with p-USC had earlier menopause (P = 0.0217), a lower rate of progesterone receptor(PR) expression (P < 0.001), and were more likely to have positive peritoneal cytology (P = 0.0464). After a median follow-up time of 40 months, 28 (46.7%) p-USC and 9 (29%) m-USC patients had progression disease, 18 (30%) and 8 (25.8%) patients died of their disease. 5-year PFSR were 51.2% and 75.3%, respectively, and 5-year OS rates were 66% and 67.4%. Kaplan-Meier survival analysis showed that p-USC was more likely to relapse than m-USC (P = 0.034), but there was no significant difference in OS. Cox regression analysis showed that lymph node metastasis and surgical approach were risk factors for OS, and myoinvasion depth ≥ 1/2 was an independent risk factor for PFS.

CONCLUSIONS

p-USC was more likely to relapse than m-USC, but there was no significant difference in OS between the two subtypes.

Moving into the modern era of molecular classification for endometrial cancer

The molecular subtypes of endometrial carcinoma (EC) were first described by The Cancer Genome Atlas (TCGA) a decade ago. Using surrogate approaches, the molecular classification has been demonstrated to be prognostic across EC patients and to have predictive implications. Starting in 2020, the molecular classification has been incorporated into multiple guidelines as part of the risk assessment and most recently into the International Federation of Gynecology and Obstetrics (FIGO) staging. This review article discusses the implementation of the EC molecular classification into clinical practice, the therapeutic implications, and the molecular and clinical heterogeneity of the EC molecular subtypes.

HER2 Status Assessment in Endometrial Serous Carcinoma: Comparative Analysis of Two Proposed Testing and Interpretation Algorithms

HER2 status is now routinely assessed in endometrial serous carcinoma (ESC) due to the reported predictive value of HER2 protein overexpression and/or gene amplification. Herein the authors compare 2 proposed testing and interpretation guidelines for HER2 in ESC. Forty-three consecutive cases of ESC that had been dually tested by both HER2 immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were interpreted using 2 sets of guidelines. Guideline set 1 (GS1) is the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines for breast cancer. Guideline set 2 (GS2) is a recent proposal that is a slight modification of the enrollment criteria for the clinical trial (NCT01367002) that demonstrated a survival benefit for anti-HER2 therapy in ESC. By IHC, GS1 and GS2, respectively classified 39.5% (17/43) and 28% (12/43) of ESC as HER2-negative, 37.2% (16/43) and 53.4% (23/43) as HER2 equivocal, and 23.2% (10/43) and 18.6% (8/43) as HER2-positive ( P > 0.05 for all). IHC and FISH were highly concordant at the extremes using either set of guidelines, as no cases were found to be IHC3+/FISH-negative or IHC 0-1+/FISH-positive. GS1 and GS2 were comparable regarding the proportion of IHC equivocal cases that were HER2 amplified by FISH (19% vs 23% respectively; [ P = 0.71]). GS1 and GS2 displayed 98% (42/43) concordance regarding the final (IHC and/or FISH-based) classification of tumors as being HER2-positive or negative, and the same 13 cases were ultimately classified as HER2 amplified using either GS1 or GS2. One "discordant" case was classified as HER2-positive using GS2 but HER2-negative using GS1 (HER2 IHC score 2+ using both guidelines, HER2:CEP17 signal ratio of 3, HER2 signal number of 3.4). Six (14%) of the 43 cases (FISH Groups: 2, 3, and 4) would require IHC results to interpret the FISH findings using GS1. Because GS1 requires that the HER2 IHC staining be observed within a homogeneous and contiguous invasive cell population, and this is not a requirement in GS2, GS2 may be better suited for ESC given its frequently heterogeneous staining pattern. Additional studies may be required on the optimal interpretation of problematic dual-probe FISH scenarios in GS2 and the necessity for IHC correlation in such scenarios. Using either set of guidelines, our findings support a reflex testing strategy of restricting FISH testing to cases that are IHC equivocal.

TERT promoter mutations and gene amplification in endometrial cancer

OBJECTIVE

To assess the clinicopathologic, molecular profiles, and survival outcomes of patients with endometrial carcinomas (ECs) harboring telomerase reverse transcriptase (TERT) hotspot mutations or gene amplification.

METHODS

ECs harboring somatic TERT promoter hotspot mutations or gene amplification (TERT-altered) were identified from 1944 ECs that underwent clinical tumor-normal sequencing from 08/2016-12/2021. Clinicopathologic variables, somatic mutation profiles, and survival outcomes of TERT-alt and TERT-wild-type EC were assessed.

RESULTS

We identified 66 TERT-altered ECs (43 TERT-mutated and 23 TERT-amplified), representing 3% of the unselected ECs across histologic subtypes. Most TERT-altered ECs were of copy number (CN)-high/TP53abn molecular subtype (n = 40, 60%), followed by microsatellite-unstable (MSI-H) or CN-low/no specific molecular profile (NSMP)(n = 13, 20% each). TERT-amplified and TERT-mutated ECs were molecularly distinct, with TERT-amplified ECs being more genomically instable and more frequently harboring TP53 and PPP2R1A alterations (q < 0.1). Compared to TERT-wild-type ECs, TERT-altered ECs were more commonly of CN-H/TP53abn molecular subtype (31% vs 57%, p = 0.001), serous histology (10% vs 26%, p = 0.004), and were significantly enriched for TP53, CDKN2A/B, and DROSHA somatic genetic alterations (q < 0.1). Median progression-free survival was 18.7 months (95% CI 11.8-not estimable [NE]) for patients with TERT-altered EC and 80.9 months (65.8-NE) for patients with TERT-wild-type EC (HR 0.33, 95% CI 0.21-0.51, p < 0.001). Similarly, median overall survival was 46.7 months (95% CI 30-NE) for TERT-altered EC patients and not reached for TERT-wild-type EC patients (HR 0.24, 95% CI 0.13-0.44, p < 0.001).

CONCLUSION

TERT-altered ECs, although rare, are enriched for CN-high/TP53abn tumors, TP53, CDKN2A/B and DROSHA somatic mutations, and independently predict worse survival outcomes.

Molecular subtyping in endometrial cancer: A promising strategy to guide fertility preservation

OBJECTIVES

To investigate the association of molecular subtype with progesterone response in patients with endometrial cancer (EC) or atypical endometrial hyperplasia (AEH).

METHODS

Premenopausal patients aged ≤48 years with tumor-normal sequencing data who received progesterone for EC/AEH from 1/1/2010-6/30/2021 were identified. Tumors were classified as POLE-ultramutated, microsatellite instability-high (MSI-H), copy number-high (CN-H), or copy number-low (CN-L) molecular subtype. Best response to progesterone was compared by subtype. Appropriate statistical tests were performed.

RESULTS

Of 20 patients, 7 (35%) had AEH and 13 (65%) had EC. Sixteen tumors (80%) were CN-L, 3 (15%) were MSI-H, and 1 (5%) was POLE-ultramutated. Median time on progesterone was 22 months (range, 3-115). Ten patients (50%) had complete response (CR); median time to CR was 9 months (range, 3-32). Four patients (20%) had stable disease (SD) and 6 (30%) had progressive disease (PD). For CN-L tumors, 10 patients (62%) had CR, 3 (19%) had SD, and 3 (19%) had PD. For MSI-H tumors, 1 patient (33%) had SD and 2 (66%) had PD. For POLE-ultramutated tumors, 1 patient had PD. Median follow-up was 48 months (range, 12-123). Four of 10 patients (40%) with CR recurred; median time from CR to recurrence was 16 months (range, 5-102).

CONCLUSION

Molecular subtype may be associated with progesterone response in patients with EC/AEH. CN-L tumors had the best response, and MSI-H tumors had the poorest. Recurrence after CR is common, and close surveillance is warranted. Larger studies investigating the role of molecular classification in medical management of EC/AEH are needed.

Clinical Behavior and Molecular Landscape of Stage I p53-Abnormal Low-Grade Endometrioid Endometrial Carcinomas

PURPOSE

The clinical significance of the p53-abnormal (p53abn) molecular subtype in stage I low-grade endometrioid endometrial carcinoma (EEC) is debated. We aimed to review pathologic and molecular characteristics, and outcomes of stage I low-grade p53abn EEC in a large international cohort.

EXPERIMENTAL DESIGN

Previously diagnosed stage I p53abn EC (POLE-wild-type, mismatch repair-proficient) low-grade EEC from Canadian retrospective cohorts and PORTEC-1&2 trials were included. Pathology review was performed by six expert gynecologic pathologists blinded to p53 status. IHC profiling, next-generation sequencing, and shallow whole-genome sequencing was performed. Kaplan-Meier method was used for survival analysis.

RESULTS

We identified 55 stage I p53abn low-grade EEC among 3,387 cases (2.5%). On pathology review, 17 cases (31%) were not diagnosed as low-grade EEC by any pathologists, whereas 26 cases (47%) were diagnosed as low-grade EEC by at least three pathologists. The IHC and molecular profile of the latter cases were consistent with low-grade EEC morphology (ER/PR positivity, patchy p16 expression, PIK3CA and PTEN mutations) but they also showed features of p53abn EC (TP53 mutations, many copy-number alterations). These cases had a clinically relevant risk of disease recurrence (5-year recurrence-free survival 77%), with pelvic and/or distant recurrences observed in 12% of the patients.

CONCLUSIONS

A subset of p53abn EC is morphologically low-grade EEC and exhibit genomic instability. Even for stage I disease, p53abn low-grade EEC are at substantial risk of disease recurrence. These findings highlight the clinical relevance of universal p53-testing, even in low-grade EEC, to identify women at increased risk of recurrence.

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.

Molecular Characterization of Endometrial Carcinomas in Black and White Patients Reveals Disparate Drivers with Therapeutic Implications

Although the incidence of endometrial carcinoma (EC) is similar in Black and White women, racial disparities are stark, with the highest mortality rates observed among Black patients. Here, analysis of 1,882 prospectively sequenced ECs using a clinical FDA-authorized tumor-normal panel revealed a significantly higher prevalence of high-risk histologic and molecular EC subtypes in self-identified Black (n = 259) compared with White (n = 1,623) patients. Clinically actionable alterations, including high tumor mutational burden/microsatellite instability, which confer benefit from immunotherapy, were less frequent in ECs from Black than from White patients. Ultramutated POLE molecular subtype ECs associated with favorable outcomes were rare in Black patients. Results were confirmed by genetic ancestry analysis. CCNE1 gene amplification, which is associated with aggressive clinical behavior, was more prevalent in carcinosarcomas occurring in Black than in White patients. ECs from Black and White patients display important differences in their histologic types, molecular subtypes, driver genetic alterations, and therapeutic targets.

SIGNIFICANCE

Our comprehensive analysis of prospectively clinically sequenced ECs revealed significant differences in their histologic and molecular composition and in the presence of therapeutic targets in Black versus White patients. These findings emphasize the importance of incorporating diverse populations into molecular studies and clinical trials to address EC disparities. This article is featured in Selected Articles from This Issue, p. 2293.

HER2 Genetic Intratumor Heterogeneity Is Associated With Resistance to Trastuzumab and Trastuzumab Emtansine Therapy in Recurrent High-Grade Endometrial Cancer

Anti-HER2 targeted therapies have recently demonstrated clinical activity in the treatment of high-grade endometrial carcinomas (ECs), particularly serous carcinomas with HER2 amplification and/or overexpression. Intratumor heterogeneity of HER2 amplification or HER2 genetic intratumor heterogeneity (G-ITH) has been associated with resistance to anti-HER2 therapies in breast and gastroesophageal cancers; however, its clinical relevance in EC is unknown. To characterize HER2 G-ITH in EC, archival specimens from a clinically annotated cohort of 57 ECs treated with trastuzumab or trasutuzmab emtansine in the recurrent (n = 38) or adjuvant (n = 19) setting were subjected to central pathology review, HER2 assessment by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), and next-generation sequencing. HER2 G-ITH, defined as HER2 amplification in 5% to 50% of tumor cells examined by FISH, was identified in 36% (19/53) of ECs and was associated with lower HER2 copy number and levels of protein expression. HER2 IHC revealed spatially distinct areas of strong expression juxtaposed with areas of low/absent expression in tumors with the "cluster" pattern of G-ITH, whereas the "mosaic" pattern was typically associated with a diffuse admixture of cells with variable levels of HER2 expression. HER2 G-ITH was frequently observed in cases with IHC/FISH or FISH/next-generation sequencing discrepancies and/or with an equivocal/negative FISH result (9/13, 69%). Although the objective response rate to anti-HER2 therapy in recurrent ECs was 52% (13/25) for tumors lacking HER2 G-ITH, none (0%, 0/10) of the patients with HER2 G-ITH achieved a complete or partial response (P = .005). HER2 G-ITH was significantly associated with worse progression-free survival (hazard ratio, 2.88; 95% CI, 1.33-6.27; P = .005) but not overall survival. HER2 IHC score, HER2/CEP17 ratio, HER2 copy number, histologic subtype, and other genetic alterations, including PIK3CA hotspot mutations, were not significantly associated with therapeutic response or survival outcomes. Treatment responses were not restricted to serous carcinomas, supporting consideration of anti-HER2 therapy in patients with HER2-positive high-grade ECs of non-serous histology. Our results demonstrate that HER2 G-ITH is an important determinant of response to trastuzumab and trastuzumab emtansine in EC, providing a rationale for the development of novel therapeutic strategies to target HER2-nonamplified resistant tumor subpopulations, such as HER2 antibody-drug conjugates with bystander effects.

Distinct histological and clinical features associated with pure uterine serous carcinoma: A single institution experience

AIM

To ascertain the clinicopathological features, survival, and prognostic factors of pure uterine serous carcinoma (pUSC) and compare its clinicopathological characteristics with those of serous-like grade-3 endometrioid endometrial carcinoma (G3-EEC).

METHOD

Consecutive patients with pUSC and p53 abnormal (p53abn) G3-EEC were retrospectively selected between 2014 and 2022. Histological and immunohistochemical features were reviewed, clinical information was collected, and survival analyses were performed.

RESULTS

Eighty-five pUSC patients (mean age: 61.6 years) were included. Histologically, pUSC showed a predominantly glandular growth pattern (80.0 %) with high-grade nuclear atypia and obvious nucleoli and 53 cases showed admixtures of architectural patterns. The p53 aberrant expression rate was 98.8 %. 41.5 %, 53.7 %, and 67.5 % of cases were classified as negative for ER, PR, and WT1, respectively. Six (12.3 %) of 49 cases had a HER2 score of 3+ by immunohistochemistry (IHC). The overall survival and progression-free survival rates were 72.9 % and 63.5 %, respectively. Advanced stage, no adjuvant therapy, and lymph node metastasis were independent risk factors for poor survival in pUSC. Twenty-five p53abn G3-EEC patients were assessed. Women with p53abn G3-EEC were on average, younger than those with pUSC (53.4 vs. 61.6 years, P < 0.001). Papillary structures were observed more commonly in pUSC (16 % vs. 36.5 %, P = 0.042). Positive PR expression was significantly associated with p53abn G3-EEC (P = 0.009). Survival did not differ significantly between the subgroups in univariate and multivariate analyses.

CONCLUSION

In this contemporary series, we affirm the suboptimal prognosis associated with pUSC, and that the survival associated with pUSC and p53abn G3-EEC are not significantly different. pUSC and p53abn G3-EEC have distinct morphological and immunohistochemical characteristics.

Nuclear β-Catenin Expression in the Context of Abnormal p53 Expression Indicates a Nonserous Histotype in Endometrial Carcinoma

The interobserver reproducibility is poor for histotyping within the p53-abnormal molecular category of endometrial carcinomas (ECs); therefore, biomarkers that improve histologic classification are useful. β-catenin has been proposed to have prognostic significance in specific clinicopathologic and molecular contexts. The diagnostic utility for β-catenin expression patterns in determining the histotype of p53-abnormal ECs has not been well studied. We identified ECs molecularly classified as "p53-abnormal." The p53-abnormal classification was assigned when (1) no POLE exonuclease domain hotspot mutations identified, (2) mismatch-repair protein expression was retained, and (3) abnormal p53 expression (null or overexpression) was present. Morphology was re-reviewed and β-catenin immunohistochemistry was scored as abnormal (nuclear) or normal (membranous, non-nuclear). Eighty ECs were identified in the "p53-abnormal" category; 27 (33.75%) were uterine serous carcinomas, and 53 were of nonserous histotype: 28 uterine carcinosarcomas (35%), 16 endometrioid carcinomas (20%), 2 clear cell carcinomas (2.5%), and 7 high-grade EC with ambiguous morphology (8.75%). All 27 uterine serous carcinomas demonstrated membranous β-catenin staining. Of the 53 nonserous ECs, 11 (21%) showed abnormal β-catenin expression: 6 endometrioid carcinomas, 4 uterine carcinosarcoma, and 1 high-grade EC with ambiguous morphology. The specificity of abnormal β-catenin expression for nonserous EC is high (100%) but the sensitivity is low (21%) with positive and negative predictive values of 100% and 60%, respectively. Our data shows that abnormal β-catenin expression in the context of p53-abnormal EC is highly specific, but not sensitive, for nonserous ECs and may be of value as part of a panel in classifying high-grade EC, particularly to exclude uterine serous carcinoma when nuclear staining is present.

Opposing Roles of SPOP Mutations in Human Prostate and Endometrial Cancers

PURPOSE

Recurrent gene mutations in speckle-type POZ protein (SPOP), the substrate-binding component of E3 ubiquitin ligase, are associated with tumor progression in prostate and endometrial cancers. Here, we characterized SPOP mutations in these cancers and explored their association with molecular and immune signatures and patient outcomes.

METHODS

There were 7,398 prostate cancer and 19,188 endometrial cancer samples analyzed for clinical and molecular profiles at Caris Life Sciences. Overall survival (OS) was analyzed using Kaplan-Meier survival curves. Statistical significance was determined using chi-square and Mann-Whitney U tests, with P values adjusted for multiple comparisons.

RESULTS

SPOP mutations were identified in 9.2% of prostate and 4.3% of endometrial cancers. Mutations clustered in the SPOP meprin and TRAF-C homology domain, with no significant overlap between cancer types. SPOP mutation was associated with differential comutation profiles and opposing tumor immune microenvironment signatures for each cancer, with greater immune infiltration in SPOP-mutated endometrial cancer. SPOP-mutated prostate and endometrial cancers displayed altered epigenetic gene expression, including opposite regulation of BRD2 transcripts. In SPOP-mutant prostate cancer, higher expression of androgen receptor-regulated transcripts and improved OS after treatment with hormonal agents were observed. In endometrial cancer, hormone receptor expression was significantly lower in SPOP-mutated tumors and differences in OS were highly dependent on the particular hotspot mutation and histologic subtype.

CONCLUSION

These data indicate that SPOP mutations drive opposing molecular and immune landscapes in prostate and endometrial cancers-suggesting a loss-of-function mechanism in prostate cancer and gain-of-function mechanism in endometrial cancer-and provide a rationale for tailored therapeutic approaches.

Integration of clinical sequencing and immunohistochemistry for the molecular classification of endometrial carcinoma

PURPOSE

Using next generation sequencing (NGS), The Cancer Genome Atlas (TCGA) found that endometrial carcinomas (ECs) fall under one of four molecular subtypes, and a POLE mutation status, mismatch repair (MMR) and p53 immunohistochemistry (IHC)-based surrogate has been developed. We sought to retrospectively classify and characterize a large series of unselected ECs that were prospectively subjected to clinical sequencing by utilizing clinical molecular and IHC data.

EXPERIMENTAL DESIGN

All patients with EC with clinical tumor-normal MSK-IMPACT NGS from 2014 to 2020 (n = 2115) were classified by integrating molecular data (i.e., POLE mutation, TP53 mutation, MSIsensor score) and MMR and p53 IHC results. Survival analysis was performed for primary EC patients with upfront surgery at our institution.

RESULTS

Utilizing our integrated approach, significantly more ECs were molecularly classified (1834/2115, 87%) as compared to the surrogate (1387/2115, 66%, p < 0.001), with an almost perfect agreement for classifiable cases (Kappa 0.962, 95% CI 0.949-0.975). Discrepancies were primarily due to TP53 mutations in p53-IHC-normal ECs. Of the 1834 ECs, most were of copy number (CN)-high molecular subtype (40%), followed by CN-low (32%), MSI-high (23%) and POLE (5%). Histologic and genomic variability was present amongst all molecular subtypes. Molecular classification was prognostic in early- and advanced-stage disease, including early-stage endometrioid EC.

CONCLUSIONS

The integration of clinical NGS and IHC data allows for an algorithmic approach to molecularly classifying newly diagnosed EC, while overcoming issues of IHC-based genetic alteration detection. Such integrated approach will be important moving forward given the prognostic and potentially predictive information afforded by this classification.

Germline drivers of gynecologic carcinosarcomas

OBJECTIVES

To describe the prevalence of germline pathogenic variants (gPVs) in endometrial and ovarian carcinosarcomas and determine if gPVs are drivers of carcinosarcoma.

METHODS

Patients with endometrial or ovarian carcinosarcomas who underwent clinical tumor-normal sequencing from 1/1/2015 to 6/1/2021 and consented to germline assessment of ≥76 cancer predisposition genes were included. In patients with gPVs, biallelic inactivation was identified through analysis of loss of heterozygosity and somatic pathogenic alterations.

RESULTS

Of 216 patients identified, 167 (77%) were diagnosed with endometrial carcinosarcoma and 49 (23%) with ovarian carcinosarcoma. Overall, 33 gPVs were observed in 29 patients (13%); 20 gPVs (61%) had biallelic loss in tumors. The rate of high-penetrance gPVs overall was 7% (16 of 216); 88% of high-penetrance gPVs had biallelic loss. In the endometrial carcinosarcoma cohort, 22 gPVs were found in 19 (11%) of 167 patients; 12 gPVs (55%) had biallelic loss in tumors, including 8 (89%) of 9 in high-penetrance gPVs. Among the ovarian carcinosarcoma cohort, 11 gPVs were found in 10 (20%) of 49 patients; 8 gPVs (73%) had biallelic loss in tumors, and all evaluable high-penetrance gPVs (n = 6) had biallelic loss. All gPVs in homologous recombination (BRCA1, BRCA2, RAD51C) and Lynch syndrome (MSH2, MSH6) genes had biallelic loss in tumors (n = 15).

CONCLUSIONS

gPVs in genes affecting homologous recombination- or Lynch-associated mismatch repair exhibited biallelic inactivation within tumors, suggesting likely drivers of gynecologic carcinosarcoma. Our data support germline testing for patients with gynecologic carcinosarcomas, given implications for treatment and risk-reduction in patients and at-risk family members.

Feasibility of shape-sensing robotic-assisted bronchoscopy for biomarker identification in patients with thoracic malignancies

OBJECTIVE

Molecular diagnostic assays require samples with high nucleic acid content to generate reliable data. Similarly, programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) requires samples with adequate tumor content. We investigated whether shape-sensing robotic-assisted bronchoscopy (ssRAB) provides adequate samples for molecular and predictive testing.

METHODS

We retrospectively identified diagnostic samples from a prospectively collected database. Pathologic reports were reviewed to assess adequacy of samples for molecular testing and feasibility of PD-L1 IHC. Tumor cellularity was quantified by an independent pathologist using paraffin-embedded sections. Univariable and multivariable linear regression models were constructed to assess associations between lesion- and procedure-related variables and tumor cellularity.

RESULTS

In total, 128 samples were analyzed: 104 primary lung cancers and 24 metastatic lesions. On initial pathologic assessment, ssRAB samples were deemed to be adequate for molecular testing in 84% of cases; on independent review of cellular blocks, median tumor cellularity was 60% (interquartile range, 25%-80%). Hybrid capture-based next-generation sequencing was successful for 25 of 26 samples (96%), polymerase chain reaction-based molecular testing (Idylla; Biocartis) was successful for 49 of 52 samples (94%), and PD-L1 IHC was successful for 61 of 67 samples (91%). Carcinoid and small cell carcinoma histologic subtype and adequacy on rapid on-site evaluation were associated with higher tumor cellularity.

CONCLUSIONS

The ssRAB platform provided adequate tissue for next-generation sequencing, polymerase chain reaction-based molecular testing, and PD-L1 IHC in >80% of cases. Tumor histology and adequacy on intraoperative cytologic assessment might be associated with sample quality and suitability for downstream assays.

Construction of the novel immune risk scoring system related to CD8+ T cells in uterine corpus endometrial carcinoma

BACKGROUND

Uterine corpus endometrial carcinoma (UCEC) is a gynecological malignant tumor with high incidence and poor prognosis. Although immunotherapy has brought significant survival benefits to advanced UCEC patients, traditional evaluation indicators cannot accurately identify all potential beneficiaries of immunotherapy. Consequently, it is necessary to construct a new scoring system to predict patient prognosis and responsiveness of immunotherapy.

METHODS

CIBERSORT combined with weighted gene co-expression network analysis (WGCNA), non-negative matrix factorization (NMF), and random forest algorithms to screen the module associated with CD8⁺ T cells, and key genes related to prognosis were selected out by univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analyses to develop the novel immune risk score (NIRS). Kaplan-Meier (K-M) analysis was used to compare the difference of survival between high- and low- NIRS groups. We  also explored the correlations between NIRS, immune infiltration and immunotherapy, and three external validation sets were used to verify the predictive performance of NIRS. Furthermore, clinical subgroup analysis, mutation analysis, differential expression of immune checkpoints, and drug sensitivity analysis were performed to generate individualized treatments for patients with different risk scores. Finally, gene set variation analysis (GSVA) was conducted to explore the biological functions of NIRS, and qRT-PCR was applied to verify the differential expressions of three trait genes at cellular and tissue levels.

RESULTS

Among the modules clustered by WGCNA, the magenta module was most positively associated with CD8⁺ T cells. Three genes (CTSW, CD3D and CD48) were selected to construct NIRS after multiple screening procedures. NIRS was confirmed as an independent prognostic factor of UCEC, and patients with high NIRS had significantly worse prognosis compared to those with low NIRS. The high NIRS group showed lower levels of infiltrated immune cells, gene mutations, and expression of multiple immune checkpoints, indicating reduced sensitivity to immunotherapy. Three module genes were identified as protective factors positively correlated with the level of CD8⁺ T cells.

CONCLUSIONS

In this study, we constructed NIRS as a novel predictive signature of UCEC. NIRS not only differentiates patients with distinct prognoses and immune responsiveness, but also guides their therapeutic regimens.

A cost-effective, machine learning-based new unified risk-classification score (NU-CATS) for patients with endometrial cancer

INTRODUCTION

Treatment for endometrial cancer (EC) is increasingly guided by molecular risk classifications. Here, we aimed at using machine learning (ML) to incorporate clinical and molecular risk factors to optimize risk assessment.

METHODS

The Cancer Genome Atlas-Uterine Corpus Endometrial Carcinoma (n = 596), Memorial Sloan Kettering-Metastatic Events and Tropisms (n = 1315) and the American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange (n = 4561) datasets were used to identify genetic alterations and clinicopathological features. Software packages including Keras, Pytorch, and Scikit Learn were tested to build artificial neural networks (ANNs) with a binary output as either intra-abdominal metastatic progression ('1') vs. non-metastatic ('0').

RESULTS

Black patients with EC have worse prognosis than White patients, adjusting for TP53 or POLE mutation status. Over 75% of Black patients carry TP53 mutations as compared to approximately 40% of White patients. Older age is associated with an increasing likelihood of TP53 mutation, high risk histology, and distant metastasis. For patients above age 70, 91% of Black and 60% of White EC patients carry TP53 mutations. A ML-based New Unified classifiCATion Score (NU-CATS) that incorporates age, race, histology, mismatch repair status, and TP53 mutation status showed 75% accuracy in prognosticating intra-abdominal progression. A higher NU-CATS is associated with an increasing risk of having positive pelvic or para-aortic lymph nodes and distant metastasis. NU-CATS was shown to outperform Leiden/TransPORTEC model for estimating risk of FIGO Stage I/II disease progression and survival in Black EC patients.

CONCLUSION

The NU-CATS, a ML-based, cost-effective algorithm, incorporates diverse clinicopathologic and molecular variables of EC and yields superior prognostication of the risk of nodal involvement, distant metastasis, disease progression, and overall survival.

Novel insights into tumorigenesis and prognosis of endometrial cancer through systematic investigation and validation on mitophagy-related signature

In-depth studies on the pathogenesis of endometrial cancer (EC) are critical because of the increasing global incidence of EC. Mitophagy, a mitochondrial quality control process, plays an important role in carcinogenesis and tumor progression. This study aimed to develop a novel mitophagy-based signature to predict the tumorigenesis and prognosis of EC. Data was downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases, and 29 mitophagy-related genes were downloaded from the Pathway Unification Database. EC patients were classified into two risk groups based on the two-key- gene signature, TOMM40 and MFN1, which were constructed using Cox regression analysis. A better prognosis was noted in the low-risk group. The model was validated for four aspects: clinical features, mutation status, clinical therapeutic response, and immune cell infiltration status. Moreover, according to the contribution to the risk model, TOMM40 was selected for further in vitro experiments. The silencing of TOMM40 inhibited mitochondrial degradation; suppressed cell proliferation; induced cell apoptosis and G1 phase cell cycle arrest; inhibited migration, invasion, and epithelial-mesenchymal transition; and suppressed cell stemness. In conclusion, the mitophagy-related risk score provides a novel perspective for survival and drug selection during the individual treatment of EC patients. TOMM40 serves as an oncogene in EC and promotes tumor progression via a mitophagy-related pathway. Thus, TOMM40 is a potential therapeutic target in EC.

Comprehensive analysis of germline drivers in endometrial cancer

BACKGROUND

We sought to determine the prevalence of germline pathogenic variants (gPVs) in unselected patients with endometrial cancer (EC), define biallelic gPVs within tumors, and describe their associations with clinicopathologic features.

METHODS

Germline assessment of at least 76 cancer predisposition genes was performed in patients with EC undergoing clinical tumor-normal Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) sequencing from January 1, 2015, to June 30, 2021. In patients with gPVs, biallelic alterations in ECs were identified through analysis of loss of heterozygosity and somatic PVs. Clinicopathologic variables were compared using nonparametric tests.

RESULTS

Of 1625 patients with EC, 216 (13%) had gPVs, and 15 patients had 2 gPVs. There were 231 gPVs in 35 genes (75 [32%] high penetrance; 39 [17%] moderate penetrance; and 117 [51%] low, recessive, or uncertain penetrance). Compared with those without gPVs, patients with gPVs were younger (P = .002), more often White (P = .009), and less obese (P = .025) and had differences in distribution of tumor histology (P = .017) and molecular subtype (P < .001). Among 231 gPVs, 74 (32%) exhibited biallelic inactivation within tumors. For high-penetrance gPVs, 63% (47 of 75) of ECs had biallelic alterations, primarily affecting mismatch repair (MMR) and homologous recombination related genes, including BRCA1,BRCA2, RAD51D, and PALB2. Biallelic inactivation varied across molecular subtypes with highest rates in microsatellite instability-high (MSI-H) or copy-number (CN)-high subtypes (3 of 12 [25%] POLE, 30 of 77 [39%] MSI-H, 27 of 60 [45%] CN-high, 9 of 57 [16%] CN-low; P < .001).

CONCLUSIONS

Of unselected patients with EC, 13% had gPVs, with 63% of gPVs in high-penetrance genes (MMR and homologous recombination) exhibiting biallelic inactivation, potentially driving cancer development. This supports germline assessment in EC given implications for treatment and cancer prevention.

Landscape of chromatin remodeling gene alterations in endometrial carcinoma

OBJECTIVE

Chromatin remodeling genes (CRGs) encode components of epigenetic regulatory mechanisms and alterations in these genes have been identified in several tumor types, including gynecologic cancers. In this study, we sought to investigate the prevalence and clinicopathological associations of CRG alterations in endometrial carcinoma (EC).

METHODS

We performed a retrospective analysis of 660 ECs sequenced using a clinical massively parallel sequencing assay targeting up to 468 genes, including 25 CRGs, and defined the presence of somatic CRG alterations. Clinicopathologic features were obtained for all cases. Immunohistochemical interrogation of ARID1A and PTEN proteins was performed in a subset of samples.

RESULTS

Of the 660 ECs sequenced, 438 (66.4%) harbored CRG alterations covered by our panel. The most commonly altered CRG was ARID1A (46%), followed by CTCF (21%), KMT2D (18%), KMT2B (17%), BCOR (16%), ARID1B (12%) and SMARCA4 (11%). We found that ARID1A genetic alterations were preferentially bi-allelic and often corresponded to altered ARID1A protein expression in ECs. We further observed that ARID1A alterations were often subclonal when compared to PTEN alterations, which were primarily clonal in ECs harboring both mutations. Finally, CRG alterations were associated with an increased likelihood of myometrial and lymphovascular invasion in endometrioid ECs.

CONCLUSION

CRG alterations are common in EC and are associated with clinicopathologic features and likely play a crucial role in EC.

Impact of immune infiltration signatures on prognosis in endometrial carcinoma is dependent on the underlying molecular subtype

OBJECTIVES

Increased numbers of tumor infiltrating lymphocytes (TIL) in endometrial cancer (EC) are associated with improved survival, but it is unclear how this prognostic significance relates to the underlying EC molecular subtype. In this explorative hypothesis-generating study, we sought to define the immune signatures associated with the molecular subtypes of EC (i.e., POLE-mutated, microsatellite unstable (MSI-high), copy number (CN)-low, and CN-high) and to determine their correlation with patient outcomes.

METHODS

RNA-sequencing and molecular subtype data of 232 primary ECs were obtained from The Cancer Genome Atlas. Deconvolution of bulk gene expression data was performed using single sample Gene Set Enrichment Analysis (ssGSEA) and Cell type Identification By Estimating Relative Subsets Of known RNA Transcripts (CIBERSORT). The association of the resultant immune signatures with overall survival was determined across molecular subtypes.

RESULTS

Statistically significant differences in enrichment were identified in 16/30 and 6/23 immune gene sets by ssGSEA and CIBERSORT, respectively. Signature of CD8+ cells in ECs of CN-high molecular subtype was associated with improved overall survival by ssGSEA (p = 0.0108), while CD8 signatures did not appear to be prognostic in MSI-high (p = 0.74) or CN-low EC molecular subtypes (p = 0.793). Of all molecular subtypes, CN-high ECs exhibited the lowest levels of CD8+ T cell infiltration. Consistent with antigen-induced T cell activation and exhaustion, enrichment for immunomodulatory receptors was predominantly observed in ECs of MSI-high and POLE-mutated molecular subtypes.

CONCLUSIONS

Deconvolution of bulk gene expression data can be used to identify populations of immune infiltrated endometrial cancers with improved survival. These data support the existence of unique mechanisms of immune resistance within molecular subgroups of the disease.

Metabolic reprogramming and interventions in endometrial carcinoma

Cancer cells are usually featured by metabolic adaptations that facilitate their growth, invasion, and metastasis. Thus, reprogramming of intracellular energy metabolism is currently one of the hotspots in the field of cancer research. Whereas aerobic glycolysis (known as the Warburg effect) has long been considered a dominant form of energy metabolism in cancer cells, emerging evidence indicates that other metabolic forms, especially oxidative phosphorylation (OXPHOS), may play a critical role at least in some types of cancer. Of note, women with metabolic syndromes (MetS), including obesity, hyperglycemia, dyslipidemia, and hypertension, have an increased risk of developing endometrial carcinoma (EC), suggesting a close link between metabolism and EC. Interestingly, the metabolic preferences vary among EC cell types, particularly cancer stem cells and chemotherapy-resistant cells. Currently, it is commonly accepted that glycolysis is the main energy provider in EC cells, while OXPHOS is reduced or impaired. Moreover, agents specifically targeting the glycolysis and/or OXPHOS pathways can inhibit tumor cell growth and promote chemosensitization. For example, metformin and weight control not only reduce the incidence of EC but also improve the prognosis of EC patients. In this review, we comprehensively overview the current in-depth understanding of the relationship between metabolism and EC and provide up-to-date insights into the development of novel therapies targeting energy metabolism for auxiliary treatment in combination with chemotherapy for EC, especially those resistant to conventional chemotherapy.

Utility of molecular subtypes and genetic alterations for evaluating clinical outcomes in 1029 patients with endometrial cancer

BACKGROUND

We investigated the utility of a molecular classifier tool and genetic alterations for predicting prognosis in Japanese patients with endometrial cancer.

METHODS

A total of 1029 patients with endometrial cancer from two independent cohorts were classified into four molecular subtype groups. The primary and secondary endpoints were relapse-free survival (RFS) and overall survival (OS), respectively.

RESULTS

Among the 265 patients who underwent initial surgery, classified according to immunohistochemistry, patients with DNA polymerase epsilon exonuclease domain mutation had an excellent prognosis (RFS and OS), patients with no specific molecular profile (NSMP) and mismatch repair protein deficiency had an intermediate prognosis, and those with protein 53 abnormal expression (p53abn) had the worst prognosis (P < 0.001). In the NSMP group, mutant KRAS and wild-type ARID1A were associated with significantly poorer 5-year RFS (41.2%) than other genomic characteristics (P < 0.001). The distribution of the subtypes differed significantly between patients with recurrence/progression and classified by sequencing (n = 764) and patients who underwent initial surgery (P < 0.001). Among patients with recurrence/progression, 51.4% had the opportunity to receive molecular targeted therapy.

CONCLUSIONS

A molecular classifier is a useful tool for determining prognosis and eligibility for molecularly targeted therapy in patients with endometrial cancer.

Molecular Profiling of Endometrial Cancer From TCGA to Clinical Practice

Molecular classification provides an objective, reproducible framework for categorization of endometrial cancers (ECs), informing prognosis and selection of therapy. Currently, the uptake of molecular classification, integration in to EC management algorithms, and enrollment in molecular subtype-specific clinical trials lags behind what it could be. Access to molecular testing is not uniform, and subsequent management (surgical, adjuvant therapy) is unacceptably variable. We are in the midst of a critical landscape change in this disease site, with increasing emphasis on the integration of molecular features in EC care that can potentially improve standard of care globally. This article summarizes the rationale for molecular classification of ECs, strategies for implementation in low and high resource settings, and actionable opportunities based on this information.

High-Sensitivity Mutation Analysis of Cell-Free DNA for Disease Monitoring in Endometrial Cancer

PURPOSE

We sought to determine whether sequencing analysis of circulating cell-free DNA (cfDNA) in patients with prospectively accrued endometrial cancer captures the mutational repertoire of the primary lesion and allows for disease monitoring.

EXPERIMENTAL DESIGN

Peripheral blood was prospectively collected from 44 newly diagnosed patients with endometrial cancer over a 24-month period (i.e., baseline, postsurgery, every 6 months after). DNA from the primary endometrial cancers was subjected to targeted next-generation sequencing (NGS) of 468 cancer-related genes, and cfDNA to a high-depth NGS assay of 129 genes with molecular barcoding. Sequencing data were analyzed using validated bioinformatics methods.

RESULTS

cfDNA levels correlated with surgical stage in endometrial cancers, with higher levels of cfDNA being present in advanced-stage disease. Mutations in cfDNA at baseline were detected preoperatively in 8 of 36 (22%) patients with sequencing data, all of whom were diagnosed with advanced-stage disease, high tumor volume, and/or aggressive histologic type. Of the 38 somatic mutations identified in the primary tumors also present in the cfDNA assay, 35 (92%) and 38 (100%) were detected at baseline and follow-up, respectively. In 6 patients with recurrent disease, changes in circulating tumor DNA (ctDNA) fraction/variant allele fractions in cfDNA during follow-up closely mirrored disease progression and therapy response, with a lead time over clinically detected recurrence in two cases. The presence of ctDNA at baseline (P < 0.001) or postsurgery (P = 0.014) was significantly associated with reduced progression-free survival.

CONCLUSIONS

cfDNA sequencing analysis in patients with endometrial cancer at diagnosis has prognostic value, and serial postsurgery cfDNA analysis enables disease and treatment response monitoring. See related commentary by Grant et al., p. 305.

[Assessment of HER2 status of carcinomas of various localizations]

A detailed description of the methodological aspects of the evaluation of HER2-status in carcinomas of such localizations as the mammary gland, pancreas, salivary glands, stomach, colon, endometrium, bladder, lungs is presented. Approaches and criteria for assessing HER2 status from methodological and clinical points of view are analyzed. The data are systematized in tables for use in practical diagnostic work.

Gastric-type adenocarcinoma of the cervix: Clinical outcomes and genomic drivers

OBJECTIVES

Gastric-type endocervical adenocarcinoma (GEA) is a rare form of cervical cancer not associated with human papilloma virus (HPV) infection. We summarize our experience with GEA at a large cancer center.

METHODS

Clinical and demographic information on all patients diagnosed with GEA between June 1, 2002 and July 1, 2019 was obtained retrospectively from clinical charts. Kaplan-Meier survival analysis was performed to describe progression-free survival (PFS) and overall survival (OS). Tumors from a subset of patients underwent next generation sequencing (NGS) analysis.

RESULTS

A total of 70 women with GEA were identified, including 43 who received initial treatment at our institution: of these 4 (9%) underwent surgery alone, 15 (35%) underwent surgery followed by adjuvant therapy, 10 (23%) were treated with definitive concurrent chemoradiation (CCRT), 7 (16%) with chemotherapy alone, and 3 (7%) with neoadjuvant CCRT and hysterectomy with or without chemotherapy. One-third (n = 14) of patients experienced disease progression, of whom 86% (n = 12) had prior CCRT. The median PFS and OS for patients with stage I GEA were 107 months (95% CI 14.8-199.2 months) and 111 months (95% CI 17-205.1 months) respectively, compared to 17 months (95% CI 5.6-28.4 months) and 33 months (95% CI 28.2-37.8 months) for patients with stages II-IV, respectively. On NGS, 4 patients (14%) had ERBB2 alterations, including 2 patients who received trastuzumab.

CONCLUSIONS

GEA is an aggressive form of cervical cancer with poor PFS and OS when diagnosed at stage II or later. Further investigation is needed to identify the optimal management approach for this rare subtype.

Uterine choriocarcinoma arising from serous carcinoma in a postmenopausal woman: an analysis of next-generation sequencing and PD-L1 immunochemistry

Background

Uterine somatic choriocarcinoma is a rare, clinically aggressive malignant tumor. They frequently concur with other cancer. However, the molecular pathogenesis between somatic choriocarcinoma and the concurrent carcinoma has rarely been addressed to date.

Case presentation

We report a 68-years old Chinese woman with a uterine choriocarcinoma arising from serous carcinoma. The patient underwent radical surgery including total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy and pelvic lymph node resection. She received 10 courses of post-operative chemotherapy. She died of disease 13 months after her surgery. Microscopically, the tumor showed a biphasic pattern of choriocarcinoma and serous carcinoma. The choriocarcinomatous component showed a combination of cytotrophoblast, intermediate trophoblast and syncytiotrophoblast with hemorrhage and necrosis. The component of serous carcinoma was characterized by solid sheets of small cells with marked nuclear atypia and occasional glandular and papillary formation. PD-L1 was exclusively expressed in the choriocarcinomatous component. Next-generation sequencing revealed that the genetic abnormalities were overlapping between the two components.

Microsatellite Instability-High Endometrial Cancers with MLH1 Promoter Hypermethylation Have Distinct Molecular and Clinical Profiles

PURPOSE

Microsatellite instability-high (MSI-H) endometrial carcinomas are underpinned by distinct mechanisms of DNA mismatch repair deficiency (MMR-D). We sought to characterize the clinical and genetic features of MSI-H endometrial cancers harboring germline or somatic mutations in MMR genes or MLH1 promoter hypermethylation (MLH1ph).

EXPERIMENTAL DESIGN

Of > 1,100 patients with endometrial cancer that underwent clinical tumor-normal sequencing, 184 had MSI-H endometrial cancers due to somatic MMR mutations or MLH1ph, or harbored pathogenic germline MMR mutations. Clinicopathologic features, mutational landscape, and tumor-infiltrating lymphocyte (TIL) scores were compared among MMR-D groups using nonparametric tests. Log-rank tests were used for categorical associations; Kaplan-Meier method and Wald test based on Cox proportional hazards models were employed for continuous variables and survival analyses.

RESULTS

Compared with patients with germline (n = 25) and somatic (n = 39) mutations, patients with MLH1ph endometrial cancers (n = 120) were older (P < 0.001), more obese (P = 0.001) and had more advanced disease at diagnosis (P = 0.025). MLH1ph endometrial cancers were enriched for JAK1 somatic mutations as opposed to germline MMR-D endometrial cancers which showed enrichment for pathogenic ERBB2 mutations. MLH1ph endometrial cancers exhibited lower tumor mutational burden and TIL scores compared with endometrial cancers harboring germline or somatic MMR mutations (P < 0.01). MLH1ph endometrial cancer patients had shorter progression-free survival (PFS) on univariate analysis, but in multivariable models, stage at diagnosis remained the only predictor of survival. For stage I/II endometrial cancer, two-year PFS was inferior for patients with MLH1ph endometrial cancers compared with germline and somatic MMR groups (70% vs. 100%, respectively).

CONCLUSIONS

MLH1ph endometrial cancers likely constitute a distinct clinicopathologic entity compared with germline and somatic MMR-D ECs with potential treatment implications.

Risk Stratification of Stage I Grade 3 Endometrioid Endometrial Carcinoma in the Era of Molecular Classification

PURPOSE

The role of adjuvant therapy in stage I grade 3 endometrioid endometrial carcinoma (EEC) is debatable. We sought to define the agreement between Post Operative Radiation Therapy in Endometrial Carcinoma 1 (PORTEC-1) high-intermediate risk (HIR) and Gynecologic Oncology Group (GOG)-99 HIR criteria, assess their concordance with The Cancer Genome Atlas molecular subtypes, and evaluate oncologic outcomes in this population.

METHODS

We identified patients with stage I grade 3 EECs who underwent surgical staging at our institution from January 2014 to January 2020. Patients were stratified into PORTEC-1 HIR, GOG-99 HIR, and The Cancer Genome Atlas molecular subtypes. Adjuvant treatment, and progression-free survival (PFS), and overall survival (OS) were analyzed.

RESULTS

Seventy-five patients were included. The agreement between PORTEC-1 and GOG-99 HIR classification was 68% (95% CI, 56.2 to 78.3), with a kappa of 0.36 (P = .001). There was no agreement between PORTEC-1 or GOG-99 HIR classification and a dichotomized molecular classification (copy number-high [CN-H] v other subtypes), with a kappa of 0.03 (P = .39) and -0.03 (P = .601), respectively. There was no difference in PFS between PORTEC-1 HIR and non-HIR (HR, 10.9; 95% CI, 0.28 to 4.21) or between GOG-99 HIR and non-HIR (HR, 1.22; 95% CI, 0.32 to 4.6) stage I grade 3 EECs. Patients with CN-H compared with non-CN-H EEC had worse PFS (HR, 5.67; 95% CI, 1.73 to 18.63) and OS (HR, 5.05; 95% CI, 1.13 to 22.5).

CONCLUSION

In surgically staged patients with stage I grade 3 EEC, PORTEC-1 and GOG-99 HIR criteria were not prognostic and did not identify CN-H patients. Patients with CN-H EEC had worse PFS and OS compared with those with other molecular subtypes. The integration of the molecular classification with recognized clinicopathologic factors may identify patients with higher-risk stage I grade 3 EEC who benefit from additional therapy.

Genomic landscape of endometrial carcinomas of no specific molecular profile

Endometrial carcinomas (ECs) classified by The Cancer Genome Atlas (TCGA) as copy number-low (also referred to as "no specific molecular profile" [NSMP]) have a prognosis intermediate between POLE-mutated and copy number-high ECs. NSMP-ECs are a heterogeneous group, however, comprising both relatively indolent and aggressive ECs. We identified a total of 472 NSMP-ECs among 1,239 ECs that underwent clinical sequencing of 410-468 cancer-related genes. Somatic mutation and copy number alteration data were subjected to unsupervised hierarchical clustering, which identified three genomic clusters. Random sampling with stratification was used to choose ~80 endometrioid ECs from each cluster, resulting in a study size of 240 endometrioid ECs as well as an additional 44 non-endometrioid NSMP-ECs. Cluster 1 (C1, n = 80) consisted primarily of NSMP-ECs with PTEN and PIK3R1 mutations, Cluster 2 (C2, n = 81) of tumors with PTEN and PIK3CA mutations and Cluster 3 (C3, n = 79) of NSMP-ECs with chromosome 1q high-level gain and lack of PTEN mutations. The majority (72.7%) of non-endometrioid NSMP-ECs mapped to C3. NSMP-ECs from C3 were more likely to be FIGO grade 3 (30%), estrogen receptor-negative/weak (54.5%) and FIGO stages III or IV. In multivariate analysis, molecular clusters were associated with worse overall survival outcomes with C3 tumors having the worst (hazard ratio: 4) and C1 tumors having the best outcome. In conclusion, NSMP-ECs are a heterogenous group of tumors and comprise both aggressive and clinically low-risk ECs that can be identified based on mutation and copy number data.

Association of immunohistochemical profiles with histotypes in endometrial carcinomas

OBJECTIVE

Although a large number of endometrial cancer patients are cured with surgery alone, there are significant numbers of patients with more aggressive variants of endometrial carcinoma for whom the prognosis remains poor. We investigated the effects of prevalence, histotypes, and immunohistochemical profiles on prognostic value in a hospital-based population.

MATERIALS AND METHODS

A retrospective study of surgically resected primary endometrial carcinoma was included. Immunohistochemical stains were performed on formalin-fixed paraffin-embedded tissue microarray sections for β-Catenin, estrogen receptor (ER), progesterone receptor (PR), HER-2, MLH1, MSH2, MSH6, PMS2, and p53.

RESULTS

Loss of mismatch repair expression was detected in 25.4% of samples (29/114, mean age 57 years) of the tumors. The following loss of expression was observed in patients: MLH1/PMS2 in 16.6% of patients, MSH6 in 7.0% of patients, MLH1 in 0.9% of patients, and MSH6/PMS2/MLH1 in 0.9% of patients. Immunohistochemistry of p53 was analyzed for 111 patients. A total of 13 patients (11.7%, mean age 64 years) had p53-abnormal expression (absent, cytoplasmic or diffuse strong positive patterns), and more than half (9/13, 69.2%) had endometrioid histotype. Abnormalities in p53 were significantly associated with histotype (p = 0.001), advanced tumor stage (p = 0.038), death of disease (p = 0.002), PR percentage (p = 0.002), and HER-2 expression (p = 0.018). Immunohistochemical nuclear localization of β-Catenin was detected in 7.1% of the cohort. The combination of p53 and nuclear β-Catenin expressions was not significantly predictive of disease-free or overall survival.

CONCLUSION

The results of this study are useful for management of endometrial cancer in patients with DNA mismatch repair, abnormal p53 expression, or nuclear localization of β-Catenin.

Histopathologic features and molecular genetic landscape of HER2-amplified endometrial carcinomas

HER2 is an established therapeutic biomarker in advanced or recurrent endometrial serous carcinoma. Current clinical guidelines recommend HER2 testing exclusively in this endometrial carcinoma (EC) subtype; however, the full spectrum of ECs harboring HER2 amplification remains ill-defined. The present study characterizes the clinicopathologic and molecular features of HER2-amplified ECs across all histologic subtypes. Retrospective analysis of our institutional cohort of 2,042 ECs subjected to targeted clinical massively parallel sequencing identified 77 (3.8%) cases with HER2 amplification, a group comprised of serous (n = 29), endometrioid (low-grade, n = 2, high-grade, n = 1) and clear cell (n = 4) carcinomas, carcinosarcomas (n = 18) and high-grade ECs with ambiguous features (HGEC, n = 23). A co-existing TP53 mutation was identified in 94% (72/77) of HER2-amplified ECs. Other recurrent genetic alterations included amplification of CCNE1 (22%) and ERBB3 (10%), FBXW7 mutations or deletions (13%), and mutations in PIK3CA (40%) and PPP2R1A (13%). The HER2 immunohistochemistry score was 2+ or 3+ for all evaluable cases (n = 61). Apart from carcinosarcomas, which often showed lower HER2 expression, particularly in the sarcomatous component, HER2 immunohistochemical staining pattern and intensity were similar across EC subtypes. Intratumor heterogeneity in HER2 expression was common and correlated with genetic heterogeneity as detected by fluorescence in-situ hybridization. These results demonstrate the frequent co-occurrence of HER2 amplification with TP53 mutation and high-grade histology, rather than being specific to serous carcinoma, per se. Overall, these findings suggest that HER2 targeted therapy may be more broadly applicable to all high-grade EC histotypes and consideration should be given to expanding therapeutic eligibility.

Endometrial cancer

Endometrial cancer is the most common gynaecological cancer in high income countries and its incidence is rising globally. Although an ageing population and fewer benign hysterectomies have contributed to this trend, the growing prevalence of obesity is the major underlying cause. Obesity poses challenges for diagnosis and treatment and more research is needed to offer primary prevention to high-risk women and to optimise endometrial cancer survivorship. Early presentation with postmenopausal bleeding ensures most endometrial cancers are cured by hysterectomy but those with advanced disease have a poor prognosis. Minimally invasive surgical staging and sentinel-lymph-node biopsy provides a low morbidity alternative to historical surgical management without compromising oncological outcomes. Adjuvant radiotherapy reduces loco-regional recurrence in intermediate-risk and high-risk cases. Advances in our understanding of the molecular biology of endometrial cancer have paved the way for targeted chemotherapeutic strategies, and clinical trials will establish their benefit in adjuvant, advanced, and recurrent disease settings in the coming years.

Mesonephric Adenocarcinoma of the Vagina Harboring TP53 Mutation

Mesonephric adenocarcinoma (MA) of the female genital tract is a rare but distinct entity, exhibiting unique morphological, immunophenotypical, and molecular characteristics. Vaginal MA is hypothesized to arise from the mesonephric remnants located in the lateral vaginal wall. A 52-year-old woman presented with vaginal bleeding. Physical examination revealed a protruding mass in the left vaginal wall. Pelvic magnetic resonance imaging revealed a 2.5-cm mass arising from the left upper vagina and extending posterolaterally to the extravaginal tissue. The punch biopsy was diagnosed as poorly differentiated adenocarcinoma. She received radical surgical resection. Histologically, the tumor displayed various architectural patterns, including compactly aggregated small tubules, solid cellular sheets, endometrioid-like glands and ducts, intraluminal micropapillae, cribriform structure, and small angulated glands accompanied by prominent desmoplastic stroma. The tubules and ducts possessed hyaline-like, densely eosinophilic intraluminal secretions. The tumor extended to the subvaginal soft tissue and had substantial perineural invasion. Immunostaining revealed positivity for the mesonephric markers, including GATA3, TTF1, and PAX2, while showing very focal and weak positivity for estrogen receptor and negativity for progesterone receptor. Additionally, we observed a complete absence of p53 immunoreactivity. Targeted sequencing analysis revealed that the tumor harbored both activating KRAS p.G12D mutation and truncating TP53 p.E286* mutation. A thorough review of the previous literature revealed that 4.5% (3/67) of vaginal/cervical MAs and 0.9% (1/112) of uterine/ovarian mesonephric-like adenocarcinomas harbor TP53 mutations, indicating that this is very uncommon in malignant mesonephric lesions. In summary, we presented a rare case of vaginal MA uniquely harboring pathogenic TP53 mutation, resulting in p53 aberration.

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

This review provides an update on immunohistochemistry applications-diagnostic, prognostic, and predictive-in the pathology evaluation of gynecologic carcinomas. The 5th edition of the WHO Classification of Female Genital Tumors introduced important changes in the diagnostic classification of lower genital tract, endometrial, and ovarian carcinomas, with major influence on the routine pathology practice. Lower genital tract carcinomas and their precursor lesions are now classified based on their human papillomavirus (HPV)-associated and HPV-independent pathogenesis, reflecting the clinically significant prognostic differences and impacting the therapeutic decision-making. Immunohistochemical markers have an increasing role in the pathology evaluation of endometrial carcinomas: in addition to their traditional use in the differential diagnosis and histologic subtyping, they have also been recently advocated for prognostic classification as surrogates for the TCGA (The Cancer Genome Atlas) molecular groups. New entities - mesonephric-like adenocarcinoma and gastric (gastrointestinal)-type mucinous adenocarcinoma of the endometrium - have also been added and often require immunostains for diagnostic confirmation. Ovarian carcinomas frequently show overlapping morphologic patterns and heterogeneous appearance within the same tumor, necessitating immunohistochemical work-up. Beyond diagnostic applications, there is increasing clinical demand for screening of inherited cancer syndromes, prediction of prognosis and guiding targeted therapy. Practical issues and pitfalls related to mismatch repair protein immunohistochemistry, HER2, and PD-L1 testing are also discussed.

The emerging role of molecular pathology in directing the systemic treatment of endometrial cancer

Following the discovery of the four molecular subtypes of endometrial cancer (EC) by The Cancer Genome Atlas (TCGA) in 2013, subsequent studies used surrogate markers to develop and validate a clinically relevant EC classification tool to recapitulate TCGA subtypes. Molecular classification combines focused sequencing (POLE) and immunohistochemistry (mismatch repair and p53 proteins) to assign patients with EC to one of four molecular subtypes: POLEmut, MMRd, p53abn and NSMP (no specific molecular profile). Unlike histopathological evaluation, the molecular subtyping of EC offers an objective and reproducible classification system that has been shown to have prognostic value and therapeutic implications. It is an exciting time in EC care where we have moved beyond treatment based on histomorphology alone, and molecular classification will now finally allow assessment of treatment efficacy within biologically similar tumours. It is now recommended that molecular classification should be considered for all ECs, and should be performed routinely in all high grade tumours. It is also recommended to incorporate molecular classification into standard pathology reporting and treatment decision-making algorithms. In this review, we will discuss how the molecular classification of EC can be used to guide both conventional and targeted therapy in this new molecular era.

Performance of a HER2 testing algorithm specific for p53-abnormal endometrial cancer

Aims

Human epidermal growth factor receptor 2 (HER2) amplification in endometrial cancer (EC) is almost completely confined to the p53‐abnormal (p53abn) molecular subtype and independent of histological subtype. HER2 testing should therefore be molecular subtype‐directed. However, the most optimal approach for HER2 testing in EC has not been fully established. Therefore, we developed an EC‐specific HER2 immunohistochemistry (IHC) scoring method and evaluated its reproducibility and performance to establish an optimal diagnostic HER2 testing algorithm for p53abn EC.

Methods and results

HER2 IHC slides of 78 p53abn EC were scored by six gynaecopathologists according to predefined EC‐specific IHC scoring criteria. Interobserver agreement was calculated using Fleiss’ kappa and the first‐order agreement coefficient (AC1). The consensus IHC score was compared with HER2 dual in‐situ hybridisation (DISH) results. Sensitivity and specificity were calculated. A substantial interobserver agreement was found using three‐ or two‐tiered scoring [κ = 0.675, 95% confidence interval (CI) = 0.633–0.717; AC1 = 0.723, 95% CI = 0.643–0.804 and κ = 0.771, 95% CI = 0.714–0.828; AC1 = 0.774, 95% CI = 0.684–0.865, respectively]. Sensitivity and specificity for the identification of HER2‐positive EC was 100 and 97%, respectively, using a HER2 testing algorithm that recommends DISH in all cases with moderate membranous staining in >10% of the tumour (IHC+). Performing DISH on all IHC‐2+ and ‐3+ cases yields a sensitivity and specificity of 100%.

Conclusions

Our EC‐specific HER2 IHC scoring method is reproducible. A screening strategy based on IHC scoring on all cases with subsequent DISH testing on IHC‐2+/‐3+ cases has perfect test accuracy for identifying HER2‐positive EC.