Mismatch Repair Protein Expression in Endometrioid Intraepithelial Neoplasia/Atypical Hyperplasia: Should We Screen for Lynch Syndrome in Precancerous Lesions?

Screening for Lynch syndrome (LS) is routinely performed in patients with endometrial carcinoma. Currently, no screening recommendations exist for LS in precancerous lesions. The study goal was to determine the incidence of abnormal protein expression in endometrioid intraepithelial neoplasia/atypical hyperplasia (EIN/AH). We analyzed mismatch repair (MMR) protein expression by immunohistochemistry in EIN/AH concurrent with MMR-deficient endometrial carcinomas, and in endometrial biopsy/curettage specimens with EIN/AH from an unselected group of patients. Of 63 patients with MMR-deficient endometrial carcinoma, 34 demonstrated loss of MLH1/PMS2 expression; 1 showed loss of PMS2 alone; 12 showed loss of MSH2/MSH6, and 15 had loss of MSH6 alone. Genetic testing identified deleterious mutations in 14 cases (LS). 15 tumors demonstrated MLH1 promoter hypermethylation. Abnormal MMR expression in EIN/AH and adjacent carcinoma was concordant in 100% of LS cases and 71% of MLH1 promoter hypermethylation cases. Of 118 patients from the unselected group with EIN/AH, 4 (3%) cases demonstrated absent expression of one or more MMR proteins. Of these, 2 patients were later confirmed to have deleterious mutations in subsequent specimens with endometrial carcinoma. The prevalence of abnormal MMR expression in EIN/AH adjacent to carcinoma and in the unselected group of patients with EIN/AH is similar to the reported prevalence of LS in endometrial carcinoma. Identifying patients at high risk f...
Source: International Journal of Gynecological Pathology - Category: Pathology Tags: Pathology of the Corpus: Original Articles Source Type: research

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Immunohistochemistry for mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 is an effective screen to detect individuals at risk for Lynch syndrome. College of American Pathologists guidelines stipulate that protein expression should be reported as present versus absent, as most patients with germline mutations in a mismatch repair gene have complete loss of protein expression in tumor cells. A similar approach is employed to screen for cancer patients eligible for immune checkpoint blockade. This “all or none” interpretive approach ignores substantial evidence that mismatch repair may be more finely regulated...
Source: International Journal of Gynecological Pathology - Category: Pathology Tags: PATHOLOGY OF THE CORPUS: ORIGINAL ARTICLES Source Type: research
CONCLUSIONS: The rate of MMR loss observed in UTUC was comparable to that in the established setting of colorectal and endometrial adenocarcinomas, supporting universal UTUC screening at our institution and others. PMID: 32789450 [PubMed - as supplied by publisher]
Source: American Journal of Clinical Pathology - Category: Pathology Authors: Tags: Am J Clin Pathol Source Type: research
CONCLUSION: This is the first report of the LS prevalence in EC screened by a universal approach in Brazil. Our findings contribute to a better understanding of the mutational landscape of this syndrome in Brazil, which is relevant for improved identification, genetic counseling, prevention and control of cancer in LS. PMID: 32694065 [PubMed - as supplied by publisher]
Source: Gynecologic Oncology - Category: Cancer & Oncology Authors: Tags: Gynecol Oncol Source Type: research
c Samuel Aguiar Junior Edenir Inez Palmero José Cláudio Casali-da-Rocha Dirce Maria Carraro Giovana Tardin Torrezan Lynch syndrome (LS) is a hereditary cancer-predisposing syndrome associated most frequently with epithelial tumors, particularly colorectal (CRC) and endometrial carcinomas (EC). The aim of this study was to investigate the relationship between sarcomas and LS by performing clinical and molecular characterization of patients presenting co-occurrence of sarcomas and tumors from the LS spectrum. We identified 27 patients diagnosed with CRC, EC, and other LS-associated tumors who had ...
Source: Cancers - Category: Cancer & Oncology Authors: Tags: Article Source Type: research
In this study, we present the clinicopathologic findings of 29 cases of LS patients that underwent risk-reducing gynecologic surgery at our institution over a period of 13 yr. Clinical-pathologic information was obtained from the patients’ charts and pathology reports. Significant pathologic abnormalities were identified in 17% (5/29) of cases, all showing endometrial hyperplasia. Four of them with atypical and 1 without atypical. All of our cases with endometrial pathology had significant findings on preoperative endometrial sampling. To further study the recommendation of in toto submission of the endometriu...
Source: International Journal of Gynecological Pathology - Category: Pathology Tags: PATHOLOGY OF THE UPPER TRACT: ORIGINAL ARTICLES Source Type: research
Lynch syndrome (LS) is an autosomal dominant disease caused by a germline mutation in DNA mismatch repair genes which increases the risk of several cancers such as endometrial and colorectal cancers. However, there are only a few reports of peritoneal malignancies in patients with LS. Herein, we report the first case of a primary peritoneal low-grade serous carcinoma in a woman with LS and provide a literature review of peritoneal malignancies in patients with LS. The patient was a 72-yr-old gravid 2 para 2 Japanese woman with a germline mutation in MLH1. She had a history of colon cancer and endometrial cancer and was tre...
Source: International Journal of Gynecological Pathology - Category: Pathology Tags: PATHOLOGY OF THE UPPER TRACT: CASE REPORTS Source Type: research
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 identifie...
Source: The American Journal of Surgical Pathology - Category: Pathology Tags: Original Articles Source Type: research
In conclusion, somatic mutational signatures suggest that conventional MMR status of tumor tissues is likely to underestimate the significance of the predisposing MMR defects as contributors to breast tumorigenesis in LS. PMID: 32292574 [PubMed]
Source: Oncotarget - Category: Cancer & Oncology Tags: Oncotarget Source Type: research
Endometrial carcinoma (EC), as described by Bokhman, has historically been classified as Type I (low-grade, hormone-dependant, young patients, good prognosis) or Type II (high-grade, hormone-independent, older patients, poor prognosis). This classification is no longer pragmatic, however, as EC is a much more heterogeneous disease. Four molecular subtypes of EC were identified by The Cancer Genome Atlas (TCGA), and subsequent studies have demonstrated its utility in predicting prognosis. While endometrial serous carcinoma (ESC), the prototypical Type II EC, largely occurs in older women, younger women with ESC were not acc...
Source: The American Journal of Surgical Pathology - Category: Pathology Tags: Original Articles Source Type: research
Mismatch repair deficiency (MMRD) is involved in the initiation of both hereditary and sporadic tumors. MMRD has been extensively studied in colorectal cancer and endometrial cancer, but not so in other tumors, such as ovarian carcinoma. We have determined the expression of mismatch repair proteins in a large cohort of 502 early-stage epithelial ovarian carcinoma entailing all the 5 main subtypes: high-grade serous carcinoma, endometrioid ovarian carcinoma (EOC), clear cell carcinoma (CCC), mucinous carcinoma, and low-grade serous carcinoma. We studied the association of MMRD with clinicopathologic and immunohistochemical ...
Source: The American Journal of Surgical Pathology - Category: Pathology Tags: Original Articles Source Type: research
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