Question

Most common mutation in Papillary cell CA?

• A. BRAF V600E
• B. RET
• C. MET
• D. RAS

Hint:

Papillary thyroid cancer is a MAPK-pathway tumour — the single most frequent driver is a V600E kinase point mutation.

Answer 1

The Correct Option is A

Step 1: Identify the tumour. "Papillary cell CA" here refers to papillary thyroid carcinoma (PTC), the most common malignancy of the thyroid, arising from follicular epithelial cells. It is recognised by branching papillae and nuclear features (Orphan-Annie eye nuclei, nuclear grooves, pseudo-inclusions).

Step 2: Recall its driver mutations. PTC is driven by activation of the MAPK signalling pathway. The single most common genetic alteration is the BRAF V600E point mutation, found in roughly 40-60% of papillary thyroid cancers, and it is associated with more aggressive behaviour.

Step 3: Select the answer. Therefore the most common mutation in papillary thyroid carcinoma is BRAF V600E - Option A.

Step 4: Why the others are wrong. (B) RET rearrangement: RET/PTC rearrangements do occur in PTC (notably radiation-induced cases) but are far less frequent than BRAF; germline point mutation of RET instead causes medullary thyroid carcinoma/MEN-2. (C) MET mutations are characteristic of other cancers (e.g., papillary renal cell carcinoma), not thyroid PTC. (D) RAS mutations are seen but are more typical of follicular thyroid carcinoma and the follicular variant, and are less common than BRAF in classic PTC.

Final Answer: Option A - BRAF V600E.