A 42-year-old woman presents with vaginal bleeding and is diagnosed with endometrial adenocarcinoma. Vital signs are stable (BP 128/82, HR 78). Her father had colon cancer at age 45, and paternal aunt had ovarian cancer at age 48. Tumor testing reveals microsatellite instability with elevated tumor mutational burden. She denies prior chemotherapy. Which of the following molecular defects involving DNA repair mechanisms is most likely responsible for her malignancy?
- A)Defect in UMP synthase
- B)Mutation in a noncoding mitochondrial tRNA gene
- C)Mutation in a mismatch repair geneGABARITO
- D)Mutation in a nucleotide excision repair gene
- E)Trinucleotide repeat expansion
Explicação
This family history and tumor profile are typical of Lynch syndrome caused by defects in DNA mismatch repair genes such as MLH1, MSH2, MSH6, or PMS2. Mismatch repair failure leads to microsatellite instability and increased risk of colorectal, endometrial, and... Ver explicação completa e trilha adaptativa →