A 50-year-old man is going to have a colonoscopy done as part of a normal checkup for colorectal cancer. He doesn't have any constipation, obvious blood in his stool, abdominal pain, altered stool consistency, or unexpected weight loss. He has no known family members who have had colon cancer. The surgery is straightforward, however a little mucosal lesion (less than 1 cm) is discovered in the patient's sigmoid colon. The image below shows the histology of the biopsy-found lesion. The pathogenesis of this patient's lesion most likely began with a mutation involving which of the following genes?

Question

A 50-year-old man is going to have a colonoscopy done as part of a normal checkup for colorectal cancer. He doesn't have any constipation, obvious blood in his stool, abdominal pain, altered stool consistency, or unexpected weight loss. He has no known family members who have had colon cancer. The surgery is straightforward, however a little mucosal lesion (less than 1 cm) is discovered in the patient's sigmoid colon. The image below shows the histology of the biopsy-found lesion.  The pathogenesis of this patient's lesion most likely began with a mutation involving which of the following genes?

Quizplus · Accepted Answer

Eductional Objective: The APC tumor suppressor gene is mutated in the majority of sporadic colon cancer cases and in every patient with familial adenomatous polyposis, marking the first stage in the traditional adenoma-to-carcinoma sequence. Mutations in DNA mismatch repair genes are the hallmark of the microsatellite instability pathway, which is linked to the occurrence of hereditary nonpolyposis colorectal cancer (Lynch syndrome).

A 50-Year-Old Man Is Going to Have a Colonoscopy Done