Women 50 Years Or Younger With Endometrial Cancer: The Argument for Universal Mismatch Repair Screening and Potential for Targeted Therapeutics

STNM1 in human cancers: role, function and potential therapy sensitizer

STMN1 belongs to the stathmin gene family, it encodes a cytoplasmic phosphorylated protein, stathmin1, which is commonly observed in vertebrate cells. STMN1 is a structural microtubule-associated protein (MAP) that binds to microtubule protein dimers rather than microtubules, with each STMN1 binding two microtubule protein dimers and preventing their aggregation, leading to microtubule instability. STMN1 expression is elevated in a number of malignancies, and inhibition of its expression can interfere with tumor cell division. Its expression can change the division of tumor cells, thereby arresting cell growth in the G2/M phase. Moreover, STMN1 expression affects tumor cell sensitivity to anti-microtubule drug analogs, including vincristine and paclitaxel. The research on MAPs is limited, and new insights on the mechanism of STMN1 in different cancers are emerging. The effective application of STMN1 in cancer prognosis and treatment requires further understanding of this protein. Here, we summarize the general characteristics of STMN1 and outline how STMN1 plays a role in cancer development, targeting multiple signaling networks and acting as a downstream target for multiple microRNAs, circRNAs, and lincRNAs. We also summarize recent findings on the function role of STMN1 in tumor resistance and as a therapeutic target for cancer.

MLH1/PMS2-deficient Endometrial Carcinomas in a Universally Screened Population: MLH1 Hypermethylation and Germline Mutation Status

MLH1/PMS2 loss due to epigenetic hypermethylation of the MLH1 promoter is the most common cause of mismatch repair deficiency in endometrial carcinoma, and typically provides reassurance against an associated germline mutation. To further characterize the genetic features of MLH1/PMS2-deficient endometrial cancers, the departmental database was searched for cases with dual MLH1/PMS2 loss and retained MSH2/6 expression which underwent MLH1 hypermethylation testing. Genetic testing results were obtained when available. One hundred seventeen endometrial cancers met inclusion criteria: 100 (85%) were MLH1-hypermethylated, 3 (3%) were low-level/borderline, 7 (6%) were nonmethylated, and 7 (6%) were insufficient for testing. Sixteen cases (12 MLH1-hypermethylated, 3 nonmethylated, and 1 insufficient for testing) underwent germline testing, 6 of which (37.5%) demonstrated germline variants of unknown significance (VUS) (MSH6, PMS2, POLD1, BRIP1, RAD51D, CHEK2) but no known deleterious mutations. Notably, however, the patients harboring the MSH6 and PMS2 germline VUS had clinical features concerning for Lynch syndrome. One nonmethylated, germline-normal case underwent somatic tumor testing, and demonstrated a somatic MLH1 mutation. In summary, MLH1-hypermethylation accounts for the vast majority of MLH1/PMS2-deficient cancers in a universally screened population, although MLH1 somatic and germline mutations can occur. Occasionally, patients with MLH1-hypermethlated tumors also bear germline VUS in other mismatch repair genes as well as genes implicated in other hereditary cancer syndromes, but their clinical relevance is unclear. Family and personal cancer histories must always be evaluated to determine the need for germline testing in women with loss of MLH1/PMS2, even in the setting of hypermethylation.

Mismatch Repair Deficiency in Uterine Carcinosarcoma: A Multi-institution Retrospective Review

Immunohistochemistry (IHC) for mismatch repair (MMR) proteins is recommended in endometrial carcinomas as a screening test for Lynch syndrome, and mismatch repair deficiency (MMRd) is reported in ∼30% of cases. However, few studies have evaluated the rate of MMR loss in uterine carcinosarcomas. A 5-year retrospective database search of uterine carcinosarcomas was performed at 3 academic institutions. The histologic diagnoses, type of carcinoma present, and MMR IHC interpretations were confirmed by a gynecologic pathologist. One hundred three cases of uterine carcinosarcomas with available MMR IHC results were identified. Ninety-nine cases (96%) showed intact expression and 4 cases (4%) showed loss of MLH1/PMS2. All MMRd carcinosarcomas identified in this series had an endometrioid carcinomatous component and wild-type p53 expression. In contrast, the majority of MMR intact carcinosarcomas had a serous morphology and aberrant p53 expression. Three additional cases initially diagnosed as carcinosarcoma also revealed MMRd; however, given the lack of clear mesenchymal differentiation, these cases were reclassified as dedifferentiated endometrial carcinomas and were subsequently excluded from the carcinosarcoma category. No cases of Lynch syndrome were identified among carcinosarcoma patients, as all 4 MMRd cases were due to somatic MLH1 hypermethylation. In summary, we found that the rate of MMRd is markedly lower in uterine carcinosarcoma when compared with endometrial carcinoma. In the setting of MMR loss, a diagnosis of dedifferentiated carcinoma should be considered as almost half of the MMRd tumors which were called carcinosarcomas initially were reclassified as dedifferentiated on review. However, given the interobserver variability in the classification of carcinosarcoma versus dedifferentiated carcinoma a universal screening approach that includes uterine carcinosarcoma is still recommended.

Clinicopathological and survival characteristic of mismatch repair status in ovarian clear cell carcinoma

BACKGROUND AND OBJECTIVES

We sought to explore the expression of mismatch repair (MMR) status and its correlation with clinicopathologic and survival characteristics in ovarian clear cell carcinoma (OCCC).

METHODS

Expression of four MMR proteins (MLH1, PMS, MSH2, and MSH6) were measured using tissue microarray-based immunohistochemistry in 120 OCCC patients. The associations of clinicopathologic parameters with recurrence-free survival (RFS) and overall survival (OS) were analyzed by the Kaplan-Meier method, and multivariate analysis was further performed by the Cox regression model.

RESULTS

Overall, 120 OCCC patients met the entry criteria, and their MMR status was detected, consisting of 24 patients with dMMR and 96 patients with proficient MMR (pMMR). Patients with dMMR were strongly associated with platinum-sensitive disease (P = .006) and large tumor volume (P = .038). Among all the patients who have received surgery, tumors with dMMR had a better RFS and OS than those with pMMR (hazard ratio [HR] for recurrence: 0.459 [95% confidence interval {95% CI} = 0.224-0.940], P = .029; HR for death: 0.381 [95% CI = 0.170-0.853], P = .015). In subgroup analysis, dMMR patients experienced a better trend of RFS (HR = 0.273; P = .055) and OS (HR = 0.165; P = .040) than pMMR cases among early stages (I-II), but this difference was not observed in advanced stage (III-IV) patients. Meanwhile, pMMR was associated with a more favorable trend of prognosis than dMMR in platinum-resistant patients (RFS: HR = 0.317, P = .051; OS: HR = 0.370, P = .046). Multivariate analysis revealed that only advanced stages (III-IV) were adverse independent prognosticators for both RFS (HR = 5.938 [95% CI = 2.804-12.574]; P < .001) and OS (HR = 6.209 [95% CI = 2.724-14.156]; P < .001).

CONCLUSION

Tumors with dMMR were related to better OS in OCCC on univariate analysis. Only the tumor stage was an independent prognosticator for both RFS and OS. MMR status is a potentially valuable prognostic index in OCCC patients, and larger prospective studies are required to validate its prognostic role.

The proportion of endometrial cancers associated with Lynch syndrome: a systematic review of the literature and meta-analysis

Purpose

Endometrial cancer (EC) is often the sentinel cancer in women with Lynch syndrome (LS). However, efforts to implement universal LS screening in EC patients have been hampered by a lack of evidence detailing the proportion of EC patients that would be expected to screen positive for LS.

Methods

Studies were identified by electronic searches of Medline, Embase, Cochrane CENTRAL and Web of Science. Proportions of test positivity were calculated by random and fixed-effects meta-analysis models. I² score was used to assess heterogeneity across studies.

Results

Fifty-three studies, including 12,633 EC patients, met the inclusion criteria. The overall proportion of endometrial tumors with microsatellite instability or mismatch repair (MMR) deficiency by immunohistochemistry (IHC) was 0.27 (95% confidence interval [CI] 0.25–0.28, I²: 71%) and 0.26 (95% CI 0.25–0.27, I²: 88%), respectively. Of those women with abnormal tumor testing, 0.29 (95% CI 0.25–0.33, I²: 83%) had LS-associated pathogenic variants on germline testing; therefore around 3% of ECs can be attributed to LS. Preselection of EC cases did increase the proportion of germline LS diagnoses.

Conclusion

The current study suggests that prevalence of LS in EC patients is approximately 3%, similar to that of colorectal cancer patients; therefore our data support the implementation of universal EC screening for LS.

Prevalence and prognostic role of mismatch repair gene defect in endometrial cancer patients

The study was to evaluate the prevalence of mismatch repair gene defect among Thai patients with endometrial cancer and its association with clinico-pathological features and survivals. The formalin fixed paraffin-embedded blocks of EMC tissue from hysterectomy specimens of patients having surgery in our institution between 1 Jan 1995 and 31 December 2016 were assessed for the immunohistochemical expression of 4 mismatch repair proteins (MLH1, PMS, MSH2, MSH 6). Mismatch repair gene defect was determined by a negative expression of at least 1 protein. Among 385 EMC patients included in the study, mean age was 57.3 ± 10.8 years with 62.3% aged ⩽ 60 years. The most frequent mismatch repair gene defect was MSH6 (38.7%), followed by PMS2 (34.3%), MLH1 (33.2%), and MSH2 (16.4%). Overall, 55.1% showed negative expression of at least one protein. We found significantly higher mismatch repair gene defect in patients aged ⩽ 60 years, with early stage disease, and negative lymph node status than the other comparative groups: 59.2% vs 48.3% for age (p = 0.037), 58.2% vs 45.2% (p = 0.027) for stage, and 58.1% vs 44.6% (p = 0.048) for nodal status. The 5-year progression-free survival, overall survival, and endometrial cancer-specific survival of patients with mismatch repair gene defect was higher than those without gene defect. The differences were statistically significant for only progression-free survival and endometrial cancer-specific survival: 87.7% (95% confidence interval = 83.0%-92.4%) vs 81.5% (95% confidence interval = 75.4%-87.6%) (p = 0.049) for progression-free survival and 91.0% (95% confidence interval = 86.9%-95.1%) vs 85.5% (95% confidence interval = 80.0%-91.0%) (p = 0.044) for endometrial cancer-specific survival, respectively. In conclusion, more than half of Thai endometrial cancer patients had mismatch repair gene defect. The patients with mismatch repair gene defect had significantly younger age (⩽ 60 years) and better prognosis in terms of early stage, negative nodal status, and longer survivals.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors

This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

PD-L1 Expression in Mismatch Repair-deficient Endometrial Carcinomas, Including Lynch Syndrome-associated and MLH1 Promoter Hypermethylated Tumors

Mismatch repair (MMR)-deficient endometrial carcinomas (ECs) bearing Lynch syndrome (LS)-associated germline mutations or sporadic MLH1 promoter hypermethylation (MLH1hm) are highly immunogenic and may represent excellent candidates for therapies targeting the programmed cell death (PD)/programmed cell death ligand-1 (PD-L1) immune checkpoint pathway. This study evaluates PD-L1 expression in MMR-deficient ECs including LS-associated and MLH1hm cases, in comparison with MMR-intact tumors. Immunohistochemistry for PD-L1/CD274 was performed on 38 MMR-deficient and 29 MMR-intact ECs. Staining was scored in the tumor and the peritumoral immune compartment. The majority of MMR-deficient tumors were PD-L1 positive (53%) in at least a subset of tumor cells. LS-associated tumors were more likely to be PD-L1 positive relative to MLH1hm tumors (70% vs. 33%, P=0.05). Only 10% of MMR-intact ECs demonstrated any tumoral PD-L1 expression; this was significantly lower than was observed in MMR-deficient tumors (P=0.0005). When reviewed by histologic grade, PD-L1 expression remained highest in LS-associated ECs followed by MLH1hm and MMR-intact carcinomas, respectively. The MMR immunohistochemical pattern most uniformly associated with PD-L1 expression was MSH6 loss. Immune PD-L1 expression was seen in 100% of MMR-deficient and 66% of MMR-intact cases. This study represents the first to characterize differences in PD-L1 expression between LS-associated and MLH1hm endometrial cancers. It demonstrates that tumoral PD-L1 expression is more common in LS-associated endometrial cancers relative to MLH1hm and MMR-intact tumors, although sporadic cancers often show PD-L1 positive immune staining. These data suggest that MMR deficiency may be a better predictor of response to PD-1/PD-L1 inhibitor therapy than tumor grade in EC, and that potential benefit may vary based on the molecular mechanism of MMR defects.

High stathmin expression is a marker for poor clinical outcome in endometrial cancer: An NRG oncology group/gynecologic oncology group study

OBJECTIVE

Gynecologic Oncology Group (GOG) 177 demonstrated that addition of paclitaxel to a backbone of adriamycin/cisplatin improves overall survival (OS) and progression-free survival (PFS) for patients with advanced or recurrent endometrial cancer. Using patient specimens from GOG-177, our objective was to identify potential mechanisms underlying the improved clinical response to taxanes. Stathmin (STMN1) is a recognized poor prognostic marker in endometrial cancer that functions as a microtubule depolymerizing protein, allowing cells to transit rapidly through mitosis. Therefore, we hypothesized that one possible mechanism underlying the beneficial effects of paclitaxel could be to counter the impact of stathmin.

METHODS

We analyzed the expression of stathmin by immunohistochemistry (IHC) in 69 specimens from patients enrolled on GOG-177. We also determined the correlation between stathmin mRNA expression and clinical outcomes in The Cancer Genome Atlas (TCGA) dataset for endometrial cancer.

RESULTS

We first established that stathmin expression was significantly associated with shorter PFS and OS for all analyzed cases in both GOG-177 and TCGA. However, subgroup analysis from GOG-177 revealed that high stathmin correlated with poor PFS and OS particularly in patients who received adriamycin/cisplatin only. In contrast, there was no statistically significant association between stathmin expression and OS or PFS in patients treated with paclitaxel/adriamycin/cisplatin.

CONCLUSIONS

Our findings demonstrate that high stathmin expression is a poor prognostic marker in endometrial cancer. Paclitaxel may help to negate the impact of stathmin overexpression when treating high risk endometrial cancer cases.

Lynch Syndrome Screening in the Gynecologic Tract: Current State of the Art

Lynch syndrome underlies approximately 5% of endometrial cancers and ∼1% of ovarian cancers. Gynecologic malignancies are often the presenting cancer in these patients. Therefore, there is considerable benefit to identifying these patients and enrolling them and affected family members in surveillance programs for secondary malignancies. The molecular basis for Lynch syndrome is a defect in the DNA mismatch repair (MMR) system. Tumors can be screened for these defects using immunohistochemistry to identify loss of MMR proteins or by enlisting polymerase chain reaction to identify the microsatellite instability that attends dysfunctional MMR. However, diagnostic confirmation of Lynch syndrome requires germline mutational testing. The algorithm for screening endometrial carcinomas for Lynch syndrome remains a subject of debate, with some studies supporting universal screening and others proposing a hybrid approach informed by clinicopathologic features. This review discusses the rationales and relative merits of current Lynch syndrome-screening approaches for endometrial and ovarian cancers and provides pathologists with an informed approach to Lynch syndrome testing in gynecologic cancers. It also addresses the clinical difficulties presented by cases with discordant screening and germline results (Lynch-like cancers) and emphasizes the critical role of strong communication with clinician and genetic counseling colleagues to ensure that the significance of a positive screening test is appropriately conveyed to patients. Finally, it discusses the need for more nuanced cost-effective analyses and the potential role for next-generation sequencing panels in future screening efforts.

Clinicopathologic Comparison of Lynch Syndrome-associated and "Lynch-like" Endometrial Carcinomas Identified on Universal Screening Using Mismatch Repair Protein Immunohistochemistry

Expanded testing for Lynch syndrome (LS) is increasingly recommended for patients with endometrial carcinomas, and immunohistochemistry (IHC) for tumor loss of mismatch-repair (MMR) protein expression is the most common primary screen. This has led to the recognition of MMR-IHC-deficient cases without identifiable mutations on directed germline sequencing. The clinical implications of such "Lynch-like" (LL) cancers are unclear. We here report the clinicopathologic features of putative familial endometrial carcinoma identified on universal MMR-IHC screening with attention to cases with discordant IHC and germline results. The files of the University of Virginia Pathology Department were retrospectively searched for all MMR-deficient endometrial carcinomas identified on screening. Cases were categorized as likely sporadic (MLH1/PMS2 loss, evidence of MLH1 promoter hypermethylation) or putative LS (PLS) (loss of MSH2/MSH6, MSH6, or PMS2). PLS cases were further subdivided into LS and LL groups on the basis of the presence or absence of a confirmatory mutation by germline testing, and the clinicopathologic features of these cases were compared. A deficiency of ≥1 MMR protein was observed in 31.4% (66/210) of endometrial carcinomas, including 26 PLS cases, 15 of which had germline testing. Directed germline sequencing confirmed LS in 46.7% (7/15); the remaining cases were classified as LL. High-grade and/or biphasic morphology was seen in 42.9% (3/7) of LS and 62.5% (5/8) of LL cases; the remaining cases showed low-grade, conventional endometrioid morphology. High level microsatellite instability was observed in 71.4% (5/7) of LL cases. The majority of cases from both groups (LS: 85.7% [6/7]; LL: 87.5% [7/8]) were low-stage (T1a/T1b). Endometrial carcinoma was the presenting malignancy in 85.7% (6/7) of LS patients and 87.5% (7/8) of LL patients. Family history was suggestive of LS in 28.5% (2/7) of LS patients and 12.5% (1/8) of LL patients. Screening algorithms based on age and cancer history would have failed to identify LS patients in 57.1% (4/7) of cases. Although universal MMR-IHC identifies endometrial carcinoma patients with LS who would have been missed using targeted screening algorithms, it also identifies cancers with discordant IHC and germline results for which the somatic versus germline origin of the MMR defect is unclear. Further study of this LL group is required before drawing definitive conclusions about their familial cancer risk.

The Significance of Mismatch Repair Deficiency in Young Patients With Endometrial Cancer

The objective of this study was to identify the tumor characteristics associated with mismatch repair deficiency in young patients with endometrial carcinoma. Young patients (45 yr old or younger) with endometrial carcinoma treated by hysterectomy in our institution between July 2001 and June 2009 were identified. The clinical and pathologic data were obtained by review of clinical records. Among the 122 cases identified, paraffin sections were available in 67 cases for immunohistochemical staining and frozen tissue available in 62 cases for microsatellite instability (MSI) analysis. Both paraffin sections and frozen tissue were available in 36 cases. Among the 67 cases with immunohistochemical staining, 22 (32.8%) showed loss of expression of at least 1 mismatch repair protein. Defective MLH1 or MSH2 expression was associated with poor prognostic factors, including a higher incidence of pelvic lymph nodes metastasis (P=0.018) and higher stage (P=0.022) for MLH1, and an increased risk of lymphovascular permeation (P=0.015) for MSH2. On the contrary, defective MSH6 protein expression was associated with a lower incidence of high-grade tumors (P=0.04). Among the 62 cases with MSI analysis, 12 (19.4%) tumors were classified as microsatellite-high (MSI-H), whereas 2 (3.2%) were classified as microsatellite-low (MSI-L). There was no difference in the pathologic characteristics between MSI-stable and MSI-H tumor. We concluded that defective mismatch repair expression is important in young patients with endometrial carcinoma, with MSH6 protein being most commonly affected. The phenotype resulting from defective MSH6 expression was different from that caused by MLH1 or MSH2 loss.

Targeted Screening With Combined Age- and Morphology-Based Criteria Enriches Detection of Lynch Syndrome in Endometrial Cancer

Endometrial cancer is associated with Lynch syndrome in 2% to 6% of cases. Adequate screening may prevent of a second cancer and incident cancers in family members via risk-reducing strategies. The goal of the study was to evaluate the detection rate of Lynch syndrome via a targeted screening approach. In 2009, we incorporated targeted Lynch syndrome screening via immunohistochemistry for MLH1, PMS2, MSH2, and MSH6, followed by MLH1 promoter hypermethylation, in select cases of endometrial carcinoma. Criteria for patient selection included (1) all patients <50 years; (2) patients of any age with tumors showing features of microsatellite instability (lower uterine segment-centered tumors, hard to classify carcinomas, increased peritumoral or tumor infiltrating lymphocytes and cases with synchronous ovarian carcinomas); (3) clinician's request based on family or personal history; and (4) ad hoc retrospective testing based on the established criteria on patients discovered on follow-up visits. By using a targeted screening approach in a 4.5-year period, approximately 2.1% of endometrial cancers (7 of 328) were potentially associated with Lynch syndrome. Therefore, targeted screening with combined age and morphology based criteria enriches detection of Lynch syndrome in endometrial cancer. However, the detection rate is lower than the rates from published series that offer universal screening.

Development of an integrated support system for hereditary cancer and its impact on gynecologic services

OBJECTIVE

Patients with hereditary cancer need an integrated support system. A recently launched project was evaluated in terms of its efficacy in screening patients with hereditary cancer at the gynecologic service.

METHODS

The project team comprised gynecologists, surgeons, medical geneticists, and certified genetic counselors (CGCs) in our hospital. At the gynecologic service, a newly developed self-administered family history questionnaire (SAFHQ) was given to patients with ovarian, endometrial, or breast cancer as well as a history of multiple cancers. After an interview, a CGC constructed a pedigree and evaluated the risk for hereditary cancer. Patients at risk were recommended by a gynecologist to receive further genetic counseling at the Department of Genetics according to the modified Bethesda criteria, Amsterdam II criteria, and National Comprehensive Cancer Network (NCCN) guidelines 2012 for breast-ovarian cancer syndrome (HBOC). The numbers of newly screened patients were compared before and after the project launch.

RESULTS

The SAFHQ was administered to 131 patients and 106 (81 %) pedigrees were constructed between August 2012 and July 2013. The number of newly screened patients according to the Bethesda criteria was 4 and 8 at 10 years before and 1 year after the project launch, respectively. Two and 31 patients met the NCCN criteria for HBOC excluding ovarian cancer alone, respectively, at these 2 time points. Of 54 patients who were recommended to undergo further counseling, 10 (19 %) visited the Department of Genetics.

CONCLUSION

After the launch of an integrated support system, the number of patients with hereditary cancers who were screened increased. The gynecologic service played a pivotal role in patient and family care.