In endometrial carcinoma, Lynch syndrome (hereditary non-polyposis colorectal cancer) is caused by defects in which genes?

• A BRCA1 and BRCA2
• B MLH1, MSH2, MSH6, and PMS2 (mismatch repair genes) ✓
• C TP53 and PTEN
• D APC and KRAS

Explanation

Lynch syndrome results from germline mutations in DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6, and PMS2 (with MSH2 mutations also inactivating EPCAM). Affected women have a 40–60% lifetime risk of endometrial carcinoma, often presenting before age 50, and a 10–12% risk of ovarian cancer. BRCA1/2 mutations increase ovarian and breast cancer risk (not endometrial). PTEN mutations cause Cowden syndrome, which also increases endometrial cancer risk but via a different mechanism.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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