Question

Which of the following is the most common genetic mutation associated with hereditary non-polyposis colorectal cancer (HNPCC)?

• A. APC gene mutation
• B. MLH1/MSH2 mutation
• C. KRAS mutation
• D. TP53 mutation

Hint:

In hereditary colorectal cancers, distinguish between polyposis (APC) and non-polyposis (mismatch repair genes) syndromes.

Answer 1

The Correct Option is B

Step 1: Understanding the question.
The question asks for the common mutation in HNPCC, also known as Lynch syndrome, which involves mismatch repair genes.
Step 2: Analyzing the options.
(A) APC gene mutation: Associated with familial adenomatous polyposis, not HNPCC.
(B) MLH1/MSH2 mutation: Correct — These are the most common in mismatch repair deficiency in HNPCC.
(C) KRAS mutation: Seen in sporadic colorectal cancers.
(D) TP53 mutation: Common in many cancers but not specific to HNPCC.
Step 3: Conclusion.
The correct answer is (B) MLH1/MSH2 mutation, as it is the most common in hereditary non-polyposis colorectal cancer.