Immunohistochemistry for mismatch repair protein deficiency in endometrioid endometrial carcinoma yields equivalent results when performed on endometrial biopsy/curettage or hysterectomy specimens

Cold ischemia time and formalin fixation time in endometrial cancer: Should breast cancer guidelines for preanalytical variables be applied to hysterectomy specimens?

OBJECTIVES

The American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) recommend cold ischemia time (cIT) be <60 min, and formalin fixation time (FFT) 6-72 h, to optimize immunohistochemistry (IHC) based on breast cancer data. We assessed whether cIT and FFT impact IHC in endometrial cancer (EC), and determined which factors affect cIT and FFT.

METHODS

Surgical EC cases from 2019 to 2023 were reviewed. cIT was calculated by subtracting time of tissue devascularization intra-operatively from time the specimen was placed in formalin. Demographics, clinicopathologic and peri-operative factors, and IHC for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and mismatch repair (MMR) proteins were compared between patients with cIT <60 min versus ≥60 min (prolonged), and compliant FFT (6-72 h) versus non-compliant FFT (<6 or > 72 h). Categorical variables were compared using χ2 tests.

RESULTS

941 patients were included in the analysis. Median cIT was 33 min. Prolonged cIT occurred in 95 (10 %) cases. African American/Black race (p < 0.001), advanced stage (p < 0.001), mini-laparotomy (p < 0.001), performance of surgical procedures beyond standard EC staging (p < 0.001), longer surgical length (p < 0.001), and increased uterine weight (p < 0.001) were independently associated with prolonged cIT. There were no significant differences in ER, PR, HER2, or MMR protein expression based on cIT or FFT.

CONCLUSION

Prolonged cIT was not associated with differences in biomarker expression via IHC at time of surgical staging for EC. Despite variability in cIT, which is largely due to non-modifiable factors, tumor molecular features remain consistent and can reliably be utilized for prognostic and therapeutic decision-making.

Excellent concordance of the molecular classification between preoperative biopsy and final hysterectomy in endometrial carcinoma

OBJECTIVE

The 2023 International Federation of Gynecology and Obstetrics classification with molecular classification shows superior discriminatory ability compared to staging systems lacking molecular data. However, the accuracy of endometrial biopsy data in molecular classification remains uncertain. This study aimed to assess the concordance of molecular classifications between preoperative biopsy and hysterectomy to predict prognosis before surgical staging.

METHODS

Endometrial biopsies and corresponding hysterectomy specimens were collected at the National Cancer Center Hospital between 2012 and 2023. Immunohistochemistry for p53 and mismatch repair (MMR) proteins and next-generation sequencing of all exons of polymerase epsilon (POLE) were performed. Given the limited number of POLE mut cases in prior studies, we prepared a POLE mut-enriched cohort. Cohen's kappa estimates were used to determine concordance for molecular and clinicopathological subgroup assignments.

RESULTS

Among 70 patients classified into four molecular subtype groups, 33 exhibited POLE mutations, 15 showed loss of MMR protein expression, 13 had p53-abnormality, and 9 had no specific molecular profile. Concordance between biopsy and hysterectomy specimens was 100% (κ = 1.000). In contrast, histological types and grades between biopsy and surgical specimens showed moderate and substantial agreement (κ = 0.420 and κ = 0.780, respectively).

CONCLUSIONS

Molecular subtypes were completely consistent with those derived from surgical specimens, demonstrating high concordance between preoperative and postoperative molecular classifications. This suggests that endometrial biopsies could reliably predict prognosis. Future studies should investigate how biopsy-based molecular profiling influences treatment planning and patient outcomes.

Colombian consensus for the molecular diagnosis of endometrial cancer

Objective: The Cancer Genome Atlas research program (TCGA) developed the molecular classification for endometrial cancer with prognostic and therapeutic utility, which was replaced by the ProMisE (Proactive Molecular Risk Classifier for Endometrial Cancer) classification by consensus and international guidelines due to its high cost. This article aims to present national recommendations from an expert consensus that allows unification and implementation of the molecular classification for women with endometrial cancer nationwide, with a rational use of resources and technology. Methods: Consensus of 36 experts in clinical oncology, oncological gynecology, pathology, and genetics, with clinical practice in the national territory. The leader group performed a literature review and structuring of questions rated 1 to 9 points. A modified nominal group technique was used. There was a face-to-face meeting with master presentations, deliberative dialogue, and Google Forms (Google LLC, Mountain View, CA, USA) questionnaire voting with analysis and discussion of responses. The non-consensual responses led to a second round of voting. The final manuscript was finally prepared and revised. Results: Seven recommendations were formulated integrating the panelist responses based on evidence, but adjusted to the Colombian context and reality. Recommendation 1. The molecular classification is recommended in all the endometrial cancers using the immunohistochemistry markers as subrogated results from the molecular profile initially proposed in the TCGA classification. Recommendation 2. The sequential test strategy is recommended, starting with the immunohistochemistry markers (p53, MLH1, MSH 2, MSH6, PMS2) simultaneously in all the patients, defining to request POLE (DNA polymerase epsilon) (if available) according to the risk classification based on the surgical piece. Recommendation 3. It is recommended, that the gynecologist oncologist should be the one to request the POLE (if available) according to the final pathology report. This test must be requested for all endometrial cancers stage I-II, except in low risk (stage IA low grade endometrioid histology without linfovascular invasion normal p53) and, stages III-IV without residual disease, without affecting the request of subrogated immunohistochemistry molecular markers upon histology. The consensus proposes that the POLE is requested after the immunohistochemistry and according to the categories in the risk classification established by the 2020 ESGO/ESTRO/ESP guidelines. Recommendation 4. It is recommended to perform immunohistochemistry for hormonal receptors for all women with endometrial cancer and the HER2 in patients with p53abn, simultaneously with the others immunohistochemistry markers. Recommendation 5. It is recommended to perform the immunohistochemistry markers (p53, MLH1, MSH2, MSH6 y PMS2) in an initial endometrial biopsy or curettage when the specimen is adequate and available. In case the initial immunohistochemistry is inconclusive, or there are histological discrepancies between the initial and definitive pathology, it is recommended to repeat the molecular profile in the surgical pathology. The immunohistochemistry markers must be reported in the pathology report according to the CAP (College of American Pathologists) recommendations, independently of the type of sample. Recommendation 6. It is recommended to perform MLH1 promoter methylation testing in patients who exhibit loss of expression of MLH1 in immunohistochemistry whether it is accompanied or not with loss of expression of PMS2. All the patients with deficient MMR (mismatch repair), should be sent for genetic counseling to rule out Lynch syndrome. Recommendation 7. It is recommended to consider the molecular classification in addition to the classical histopathological criteria when making adjuvant judgments, as incorporated by the classification of prognostic groups of the 2020 ESGO/ESTRO/ESP guidelines. Conclusions: It is necessary to implement the molecular classification of endometrial cancer in clinical practice in accordance to the Colombian context, due to its prognostic and probably predictive value. This will enable the characterization of the Colombian population in order to offer individualized guided treatments. This is an academic and nonregulatory document.

Can mismatch repair status be added to sentinel lymph node mapping algorithm in endometrioid endometrial cancer?

OBJECTIVE

To evaluate the relation between mismatch repair (MMR) status and the risk of lymph node metastasis in endometrial cancer, and whether this additional data can be incorporated to current SLN (sentinel lymph node) algorithm.

METHODS

We included a series of 332 women that underwent SLN mapping ± systematic lymphadenectomy from January 2013 to December 2021. Protein expressions of MLH1, MSH2, MSH6, PMS2 were examined by immuno-histochemistry and considered MMRd (deficient) when at least one protein was not expressed.

RESULTS

MMRd was noted in 20.8% of cases and correlated to grade 3 (p = 0.018) and presence of lymphovascular space invasion (p = 0.032). Moreover, MMRd was an independent risk factor for lymph node metastasis (OR 2.76, 95% CI 1.36-5.62). Notably, 21.7% (15/69) cases with MMRd had lymph node metastasis compared to 9.5% (25/263) of cases with MMRp (proficient) (p = 0.005). The overall and bilateral SLN detection rates were 91.9% and 75.9%, respectively. Of the 80 (24%) cases of non-bilateral SLN detection, 66.2% had low-grade tumors (G1/G2) and myometrial invasion <50%. Considering MMR status an independent prognostic factor for lymph node metastasis, a systematic lymphadenectomy (side specific or bilateral) would forgo in 53.7% (43/80) of cases with non-bilateral detection, representing 13% (43/332) of all endometroid tumors.

CONCLUSION

MMR status was independently related to lymph node metastasis in endometrioid EC. Moreover, MMR status may help to select patients that can forgo systematic lymphadenectomy in case of undetected SLN.

Epigenetic MMR defect identifies a risk group not accounted for through traditional risk stratification algorithms in endometrial cancer

Purpose

We sought to evaluate the contribution of mismatch repair (MMR) status to traditional risk stratification algorithms used to predict nodal involvement and recurrence in a large single-institution cohort.

Methods

Endometrioid endometrial cancer (EC) cases from 2014-2020 were evaluated. MMR immunohistochemistry (IHC) was performed universally. Uterine factors assessed in the Mayo criteria were used to retrospectively classify patients as low or high risk for lymphatic spread. Patients were classified according to risk for recurrence using GOG 99 and PORTEC criteria. Associations were evaluated using chi-square and t-tests and contributing factors assessed using logistic regression models.

Results

1,514 endometrioid EC were evaluated; 392 (25.9%) were MMR (MMR) deficient of which 80.4% of MMR defects were associated with epigenetic silencing of MLH1. Epigenetic MMR defects were significantly more likely to be high risk for lymph node (LN) metastasis based on Mayo criteria (74.9% vs 60.6%, p=<0.001) and with the presence of LN metastasis (20.3 vs 10.5%, p=0.003) compared to MMR proficient tumors. Tumors with epigenetic MMR defects were significantly more likely to be classified as high or high intermediate risk using GOG99 and PORTEC criteria. Furthermore, cases with epigenetic MMR defects classified as low or low intermediate risk were significantly more likely to recur (GOG99 p=0.013; PORTEC p=0.008) and independently associated with worse disease-free survival (DFS). MMR status was found to be independently associated with worse DFS (HR 1.90; 95% CI 1.34-2.70; p=0.003) but not overall survival.

Conclusion

While MMR deficient EC has been associated with poor prognostic features in prior reports; we demonstrate that only epigenetic MMR defects have poorer outcomes. Epigenetic MMR defect were independently associated with lymph node metastasis after controlling for risk criteria. Epigenetic MMR deficiency was found to be an independent predictor of recurrence beyond the factors considered in traditional risk stratification algorithms. Traditional uterine-based risk stratification algorithms may not fully reflect the risk for recurrence in MMR deficient tumors. Consideration should be given to implementing MMR status and MLH1 hypermethylation alongside traditional risk stratification algorithms. Performing MMR IHC on preoperative pathologic specimens may aid in risk stratification and patient counseling.

Endometrial Cancer Following Levonorgestrel-Releasing Intrauterine System Insertion in Young Women with Atypical Hyperplasia: Two Case Reports and Literature Review

Levonorgestrel-releasing intrauterine system (LNG-IUS) insertion is the first-line treatment for atypical hyperplasia (AH) in young women who wish to retain their fertility. However, the procedure is not always effective, and may allow AH to progress to endometrioid endometrial cancer (EEC). Two young women with AH who wished to preserve their fertility developed EEC following 52-mg LNG-IUS in insertion at our institution. One was a 34-year-old woman diagnosed with endometrial cancer 2 years after LNG-IUS insertion. The second was a 30-year-old woman diagnosed 17 months after LNG-IUS insertion. Proactive molecular risk classification for endometrial cancer (ProMisE) classification revealed that the first and second patients had p53-abnormal (p53abn) EEC and mismatch repair deficient (MMR-d) EEC, respectively. MMR-d and p 53abn were frequently observed in both AH and EEC specimens. Studies suggest that MMR-d and p53abn are predictors of the occurrence adverse effects after fertility-preserving treatment for EEC. AH is a precursor of EEC. Therefore, p53 and mismatch repair (MMR) mutation may be used to identify women with AH who will not likely benefit from progestin therapy. Molecular assays in women with AH will likely be useful for identifying novel predictive biomarkers of progestin resistance and to improve the safety of conservative treatment. Combined assessment of progesterone receptor (PR) with these predictive molecular markers may improve the predictive ability.

Prevalence of DNA Mismatch Repair Deficiency in Endometrial Cancer Using Immunohistochemistry

Background: Endometrial cancer (EC) is known as the most common malignancy of the female reproductive system, suggested to be associated with hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome (LS). Objectives: Therefore, the aim of the present study was to screen for LS in patients with EC using immunohistochemistry (IHC). Methods: In this retrospective cross-sectional study, the patients with EC, referred to Qaem Hospital, Mashhad, Iran, from 2015 - 2019, were enrolled. Paraffin-embedded tissue blocks were then examined via IHC for the expression of four mismatch repair (MMR) proteins, including MLH1, MSH2, MSH6, and PMS2. The demographic and tumor-related data were also extracted from medical records and pathology reports. The data were consequently analyzed at the significance level of P < 0.05. Results: A total number of 100 patients with EC were evaluated using IHC, and 12 (12%) cases were found suspected. As well, no significant relationship was observed between LS and age, tumor site, tumor histology, tumor size, tumor grade, tumor-infiltrating lymphocytes (TILs), and a family/personal history of malignancies. Conclusions: The prevalence of LS based on the IHC expression of the MMR proteins (MLH1, MSH2, MSH6, and PMS2) was 12% in the patients with EC. There was also no significant relationship between the cases suspected and the demographic and tumor-related data.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

Identifying patients with Lynch syndrome using a universal tumor screening program in an integrated healthcare system

INTRODUCTION

Lynch syndrome (LS) is associated with an increased risk of colorectal (CRC) and endometrial (EC) cancers. Universal tumor screening (UTS) of all individuals diagnosed with CRC and EC is recommended to increase identification of LS. Kaiser Permanente Northwest (KPNW) implemented a UTS program for LS among individuals newly diagnosed with CRC in January 2016 and EC in November 2016. UTS at KPNW begins with immunohistochemistry (IHC) of tumor tissue to determine loss of mismatch repair proteins associated with LS (MLH1, MSH2, MSH6, and PMS2)., IHC showing loss of MLH1 is followed by reflex testing (automatic testing) to detect the presence of the BRAF V600E variant (in cases of CRC) and MLH1 promoter hypermethylation to rule out likely sporadic cases.

MATERIALS AND METHODS

Individuals newly diagnosed with CRC and EC were identified between the initiation of the respective UTS programs and July 2018. Electronic medical records were reviewed to extract patient data related to UTS, including IHC and reflex testing results, date of referrals to the genetics department, and results of germline genetic testing for LS.

RESULTS

313 out of 362 individuals diagnosed with CRC and 61 out of 64 individuals diagnosed with EC who were eligible were screened by IHC for LS. Most (47/52 or 90%, including 46/49 CRC and 1/3 EC) individuals that were not screened by IHC only had a biopsy sample available. Fourteen individuals (3.7% overall, including 13/313 CRC and 1/61 EC) received an abnormal result after reflex testing and were referred for genetic counseling. Of these, 10 individuals (71% overall, including 9/13 CRC and 1/1 EC) underwent germline genetic testing for LS. Five individuals diagnosed with CRC were found to have pathogenic variants. in PMS2 (n = 3), MLH1 (n = 1), and MSH6 (n = 1). No pathogenic variants were identified in individuals diagnosed with EC.

CONCLUSIONS

UTS identified individuals at risk for LS. Most individuals who screened positive for LS had follow-up germline genetic testing for LS. The consistent use of biopsy samples is an opportunity to improve UTS.

Evaluation of a nationwide Dutch guideline to detect Lynch syndrome in patients with endometrial cancer

OBJECTIVE

In the Netherlands a nationwide guideline was introduced in 2016, which recommended routine Lynch syndrome screening (LSS) for all women with endometrial cancer (EC) <70 years of age. LSS consists of immunohistochemical (IHC) staining for loss of mismatch repair (MMR) protein expression, supplemented with MLH1 methylation analysis if indicated. Test results are evaluated by the treating gynaecologist, who refers eligible patients to a clinical geneticist. We evaluated the implementation of this guideline.

METHODS

From the nation-wide pathology database we selected all women diagnosed with EC < 70 years of age, treated from 1.6.2016-1.6.2017 in 14 hospitals. We collected data on the results of LSS and follow up of cases with suspected LS.

RESULTS

In 183 out of 204 tumours (90%) LSS was performed. In 41 cases (22%) MMR protein expression was lost, in 25 cases due to hypermethylation of the MLH1 promotor. One patient was known with a pathogenic MLH1 variant. The option of genetic counselling was discussed with 12 of the 15 remaining patients, of whom three declined. After counselling by the genetic counsellor nine patients underwent germline testing. In two no pathogenic germline variant was detected, two were diagnosed with a pathogenic PMS2 variant, and five with a pathogenic MSH6 variant, in concordance with the IHC profiles.

CONCLUSION

Coverage of LSS was high (90%), though referral for genetic counselling could be improved. Gynaecologists ought to be aware of the benefits and possible drawbacks of knowing mutational status, and require training in discussing this with their patients.

Evaluating Mismatch Repair/Microsatellite Instability Status Using Cytology Effusion Specimens to Determine Eligibility for Immunotherapy

CONTEXT.—

The approval of pembrolizumab for treatment of patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) advanced cancers has led to increased requests for MSI and/or MMR immunoperoxidase (IPOX) testing. Diagnoses for patients with advanced-stage cancer are frequently made from cytology specimens.

OBJECTIVE.—

To investigate the feasibility of using cell block (CB) preparations of effusions for MMR IPOX evaluation.

DESIGN.—

Surgical pathology cases of colorectal and endometrial carcinomas with known MMR/MSI status and matched effusions with available CBs were identified. Cell block sections were evaluated for adequacy and stained with MMR IPOX (MSH2, MSH6, MLH1, and PMS2). The CBs were reviewed, the number of tumor cells quantified, and MMR IPOX was interpreted as retained, lost, suboptimal, or noncontributory.

RESULTS.—

We identified 748 cases with MMR/MSI testing on surgical specimens having matched effusions. Of these, 131 cases (17.5%) had an available CB and 53 were deemed adequate for MMR IPOX staining. MMR IPOX results between effusion CBs and surgical pathology specimens were concordant in 45 of 53 (85%), inconclusive in 6 of 53 (11%), and discordant in 2 of 53 (4%) cases.

CONCLUSIONS.—

There was high concordance of MMR IPOX testing between cytologic and surgical specimens, with no false-positive and 2 false-negative CB results. Limited tumor cells, staining in cells indefinite as tumor, tumor staining heterogeneity, and lack of internal control staining were problematic in some cases. Our findings indicate that cytologic effusion specimens may be suitable substrates for MMR IPOX biomarker testing; however, inconclusive cases need to be interpreted with caution.

Utility of the immunohistochemical analysis of DNA mismatch-repair proteins in endometrial hyperplasia

The utility of the expression lack of DNA mismatch-repair (MMR) proteins in the detection of Lynch syndrome in endometrial hyperplasia as precursor lesion of endometrial carcinoma has not been well-established. The study investigated the immunoexpression pattern of MMR proteins in endometrial hyperplasia from Tunisian patients. We carried out a retrospective study of 60 endometrial hyperplasias diagnosed among Tunisian patients. Expression of MLH1, MSH2, MSH6, and PMS2 proteins was performed by immunohistochemistry on whole-slide sections of archival tissues. Analysis of MLH1 promoter methylation and microsatellite alterations was conducted in appropriate cases. Microsatellite instability screening was assessed using the Bethesda panel, including BAT25, BAT26, D17S250, D2S123, and D5S346 markers. Expression of MMR proteins was observed in all hyperplasias without atypia as well as in 27 out of 29 atypical hyperplasias. Only two atypical hyperplasias exhibited expression loss of MMR proteins. A single case revealed MSH6 expression lack. Expression loss of MLH1 and PMS2 was identified in another atypical hyperplasia and was associated with hypermethylation of MLH1 promoter. This patient had no familial history of endometrial cancer at the diagnostic time. The two deficient MMR cases showed microsatellite stable pattern. In conclusion, only two endometrial hyperplasias displayed an altered pattern of MMR expression. Our results suggest the limited utility of the immunohistochemical analysis of MMR protein in the early detection of Lynch syndrome in Tunisian patients diagnosed with endometrial hyperplasias. Multicenter studies with larger sample size are needed to more explore these findings.

Current Systemic Treatment Landscape of Advanced Gynecologic Malignancies

Developments in systemic therapies beyond traditional cytotoxic chemotherapy have resulted in an unparalleled number of US Food and Drug Administration approvals in the past 5 years for ovarian, endometrial, and cervical cancer. In this review, we highlight registration trials leading to recent Food and Drug Administration approvals for targeted systemic therapies in advanced gynecologic malignancies, encompassing three classes of agents: the antiangiogenic anti-vascular endothelial growth factor antibody bevacizumab in ovarian and cervical cancer, poly (ADP-ribose) polymerase inhibitors in ovarian cancer, and the immune checkpoint inhibitor pembrolizumab in cervical and endometrial cancer. The addition of bevacizumab to chemotherapy has been approved in frontline and relapsed advanced ovarian cancer, in both platinum-resistant and platinum-sensitive settings. Three poly (ADP-ribose) polymerase inhibitors are approved for women with ovarian cancer. Olaparib and rucaparib are utilized in recurrent germline or somatic BRCA mutated ovarian cancer. Along with a third poly (ADP-ribose) polymerase inhibitor, niraparib, they are also Food and Drug Administration approved as maintenance therapy regardless of BRCA mutation status for patients with recurrent ovarian cancer in complete or partial response to platinum-based chemotherapy. More recently, olaparib was approved as maintenance therapy for BRCA mutated ovarian cancer following first-line platinum-based chemotherapy. Pembrolizumab has been approved for relapsed cervical cancer with programmed death ligand 1 positivity and relapsed solid tumors with mismatch repair deficiency, which applies to 30% of endometrial cancers. Together, these therapies represent the advent of personalized medicine in gynecologic malignancies. Additional information is required to determine cost-effective strategies for incorporating these therapies and rational means of sequencing these agents.

Immunohistochemical Markers With Potential Diagnostic, Prognostic, and Therapeutic Significance in Uterine Carcinosarcoma: A Clinicopathologic Study of 43 Cases

Uterine carcinosarcomas (UCS) are rare and highly aggressive tumors. Although it is currently accepted that the majority of UCS are metaplastic carcinomas, their aggressive behavior is unparalleled to that of any other high-grade endometrial neoplasms. Therefore, the search for the distinct immunohistochemical and molecular features that could help in the development of new treatment strategies continues. We evaluated the expression of PDL-1, growth hormone releasing hormone receptor, p53, WT1, PAX-8, estrogen receptor, HNF-1, and mismatch repair proteins in 43 UCS. Tumors were selected from the archives of the Magee-Womens Hospital University of Pittsburgh Medical Center Department of Pathology. Seventeen were stage I, 4 were stage II, 15 were stage III, and 7 were stage IV. The median age was 67 yr and median overall survival was 3.2 yr. Immunostaining for PAX8, HNF-1, and estrogen receptor showed statistically significant difference between epithelial and stromal components. Expression of p53 was significantly associated with clinical high stage, but other markers did not correlate with stage or survival. Immunostaining for programmed death ligand-1 was strongly positive in 30 UCS (70%), including 24 cases with tumor cell positivity, 12 cases with tumor cell and tumor-infiltrating immune cell positivity, and 6 cases with tumor-infiltrating immune cell positivity only. Of 27 tumors tested for mismatch repair expression, 12 (44%) showed loss of expression, 7 of which were PDL-1 positive. Growth hormone releasing hormone receptor was positive in 38 tumors (88%) and predominantly expressed in the epithelial component. The range of positivity for programmed death ligand-1 and growth hormone releasing hormone receptor suggests a possible potential adjuvant treatment that may be considered for UCS.

Incidence of Mismatch Repair Protein Deficiency and Associated Clinicopathologic Features in a Cohort of 104 Ovarian Endometrioid Carcinomas

Patients with Lynch syndrome have up to a 24% risk of developing ovarian carcinoma, but universal mismatch repair (MMR) protein testing of ovarian carcinomas is not standard practice in most institutions. We reviewed 104 unselected ovarian endometrioid carcinomas (OEC) for various clinicopathologic features to determine if any are predictive of MMR loss. Immunohistochemistry for all 4 MMR proteins was performed followed by MLH1 promoter methylation analysis when indicated. Overall, patients had a mean age of 55 years and tumors averaged 12 cm. Most (72%) patients had stage I tumors, 63% were grade 1, and 30% had a synchronous stage IA endometrial endometrioid carcinoma. Peritumoral lymphocytes and intratumoral stromal inflammation were rare, but tumor-infiltrating lymphocytes averaged 47/10 high-power fields. Endometriosis was noted in 71%, adenofibromatous background in 14%, and both in 14% of tumors. Metaplastic changes were common and included squamous metaplasia (63%), clear cell change (32%), mucinous differentiation (24%), and sex cord-like elements (13%). When follow-up was available (n=99), 78% of patients were alive and well, 12% died from disease, 6% died from other causes, and 4% were alive with disease. Unmethylated, MMR-deficient OECs were identified in 7% of the cohort and included MSH2/MSH6 (n=4), MSH6 (n=2), and PMS2 (n=1). All these tumors were stage I, 71% grade 1, and 57% had a synchronous endometrial endometrioid carcinoma. Among patients in this group with follow-up (n=5), all were alive without evidence of disease (mean 150 mo). Given that no clinicopathologic features were associated with MMR deficiency on univariate analysis, this study highlights the importance of universal MMR screening in OECs.

Quantitative next-generation sequencing-based analysis indicates progressive accumulation of microsatellite instability between atypical hyperplasia/endometrial intraepithelial neoplasia and paired endometrioid endometrial carcinoma

Atypical hyperplasia/endometrial intraepithelial neoplasia is an accepted precursor to endometrioid-type endometrial carcinoma. Mismatch repair-deficient endometrial carcinomas are also known to be a biologically and clinically distinct subset of tumors. However, the development of microsatellite instability in endometrial carcinogenesis has not yet been evaluated by novel next-generation sequencing-based methods. We examined 17 mismatch repair-deficient endometrioid endometrial carcinomas and their paired atypical hyperplasia/endometrial intraepithelial neoplasia precursors using a next-generation sequencing panel with quantitative microsatellite instability detection at 336 loci. Findings were compared to histological features, polymerase chain reaction-based microsatellite instability testing, immunohistochemical expression of mismatch repair proteins, and tumor mutational burden calculations. All 17 endometrial carcinomas and 8/17 atypical hyperplasia/endometrial intraepithelial neoplasia showed microsatellite instability by next-generation sequencing-based testing. Endometrial carcinoma specimens showed significantly more unstable microsatellite loci than paired atypical hyperplasia/endometrial intraepithelial neoplasia (mean: 40.0% vs 19.9 unstable loci, respectively). Out of nine microsatellite-stable atypical hyperplasia/endometrial intraepithelial neoplasia specimens, four showed mismatch repair loss by immunohistochemistry. All atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens with microsatellite instability were also mismatch repair-deficient by immunohistochemistry. Tumor mutational burden was significantly greater in endometrial carcinoma than in paired atypical hyperplasia/endometrial intraepithelial neoplasia specimens, and tumor mutational burden was significantly correlated with percent unstable microsatellite loci. Paired atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens show progressive accumulation of unstable microsatellite loci following loss of mismatch repair protein expression. Comprehensive next-generation sequencing-based testing of endometrial carcinomas offers new insights into endometrial carcinogenesis and opportunities for improved tumor surveillance, diagnosis, and management.

Molecular classification of endometrial carcinoma applied to endometrial biopsy specimens: Towards early personalized patient management

BACKGROUND

The current risk stratification systems used to guide management of endometrial cancer are based on irreproducible post surgical pathological information, hence the need for more reliable classification systems. Using microarray and sequencing technologies, TCGA recently identified four prognostically significant endometrial carcinoma subtypes, which subsequently proved reproducible using clinically applicable surrogate tests. Using these tests, we sought to determine the level of concordance between endometrial biopsies and subsequent hysterectomy specimens in assessing the molecular classification of endometrial carcinoma.

MATERIALS AND METHODS

Fifty biopsies with corresponding hysterectomy specimens for endometrial carcinomas were collected. Additionally, 10 cases of biopsy proven atypical hyperplasia/EIN who were found to have endometrial carcinoma on resection were included. IHC for mismatch repair (MMR) proteins (MLH1, PMS2, MSH2 and MSH6) and P53 was performed. Microsatellite instability analysis was performed by PCR and Sanger sequencing was performed to detect mutations in exons 9 and 13 of the POLE gene. The level of concordance for tumor grade, histologic subtype, immunohistochemical and molecular profile in both specimens was determined using Cohen's kappa estimates.

RESULTS

A high level of concordance was achieved for MMR-loss, MSI-high, P53-wild and abnormal types. In contrast, grade and histologic subtype showed only moderate levels of agreement. POLE gene mutation was detected in two patients. For both cases, mutations were detected only in resection specimens. When comparing atypical hyperplasia/EIN with subsequent hysterectomy tumor, the profile was identical to that of endometrial carcinoma.

CONCLUSION

In our cohort of endometrial carcinoma, a high level of concordance was achieved between biopsy and hysterectomy specimens for MMR-loss, MSI-high, P53-wild and abnormal types, superior to that of grade and histologic subtype, providing earlier and more reliable prognostic information to inform management. Similar concordance could not be achieved for POLE mutation, given the low frequency of this mutation in our study.

Aurora-A Induces Chemoresistance Through Activation of the AKT/mTOR Pathway in Endometrial Cancer

Endometrial cancer (EC) is the most common gynecological tumor all over the world, and advanced/metastatic EC remains a malignancy with poor survival outcome due to highly resistant to conventional chemotherapeutic treatment. Here, we report that Aurora-A, a serine-threonine kinase, plays a vital role in chemoresistance of EC. Aurora-A is overexpressed in EC tissues, compared with normal endometrium and Aurora-A expression is associated with decreased overall survival. Overexpression of Aurora-A in EC cell lines (Ishikawa and HEC-1B cells) promotes cell proliferation and induced paclitaxel- and cisplatin-resistance. Furthermore, Aurora-A activating AKT-mTOR pathway further induces chemoresistance in vitro, consistent with a positive correlation between Aurora-A and phosphorylated AKT/4E-BP1 expression in EC tissues. In summary, our study provides the strong evidence that Aurora-A controls the sensitivity of EC cell lines to chemotherapy via AKT/mTOR pathway, indicating that pharmacologic intervention of Aurora-A and AKT/mTOR in combination with chemotherapy may be considered for the targeted therapy against EC with overexpression of Aurora-A.

Interpretation of Mismatch Repair Protein Immunohistochemistry in Endometrial Carcinoma Should Consider Both Lynch Syndrome Screening and Immunotherapy Susceptibility: An Illustrative Case Report

We present an instructive case of FIGO grade 1 endometrioid endometrial carcinoma with a biphasic morphology, corresponding to subclonal loss of mismatch repair proteins (MMRP) MLH1 and PMS2 by immunohistochemistry and subclonal microsatellite instability. A pulmonary metastasis represented only the tumor component with retention of MMRPs. This case illustrates the need for pathologists to recognize and report heterogenous expression of MMRPs in endometrial carcinoma, to consider tumor heterogeneity when selecting foci for molecular studies, and to re-evaluate MMRP expression in tumor metastases, when clinically indicated. These considerations are particularly important as the relevance of MMRP expression in endometrial cancer expands beyond Lynch syndrome screening, into a new role as a predictive marker for immunotherapy.