Question:medium
Most common mutation in Papillary cell CA?
Most common mutation in Papillary cell CA?
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Papillary thyroid cancer is a MAPK-pathway tumour — the single most frequent driver is a V600E kinase point mutation.
Updated On: Jun 22, 2026
- BRAF V600E
- RET
- MET
- RAS
Show Solution
The Correct Option is A
Solution and Explanation
Pathway-centred view.
Papillary thyroid carcinoma is a MAPK-pathway disease: nearly every case is driven by a mutually exclusive lesion that switches on RAS→RAF→MEK→ERK signalling. The candidates are BRAF, RET/PTC fusions and RAS - the trick is ranking them by frequency.
Ranking by prevalence in classic PTC:
1. $BRAF\ V600E$ - the dominant single mutation, present in about $40\text{-}60\%$ of cases; a constitutively active serine/threonine kinase that drives ERK signalling and confers a more aggressive phenotype.
2. RET/PTC rearrangement - second, enriched in radiation-exposed and paediatric tumours.
3. RAS - more linked to follicular-pattern thyroid tumours than classic PTC.
So the "most common" answer is BRAF V600E - Option A.
Disqualifying the rest with disease-association cues:
• RET as a germline POINT mutation → medullary carcinoma / MEN-2, a different tumour.
• MET → think hereditary papillary RENAL cell carcinoma, not thyroid.
• RAS → follicular carcinoma / follicular-variant PTC, lower frequency in classic PTC.
Final: BRAF V600E is the commonest mutation of papillary thyroid carcinoma.
Papillary thyroid carcinoma is a MAPK-pathway disease: nearly every case is driven by a mutually exclusive lesion that switches on RAS→RAF→MEK→ERK signalling. The candidates are BRAF, RET/PTC fusions and RAS - the trick is ranking them by frequency.
Ranking by prevalence in classic PTC:
1. $BRAF\ V600E$ - the dominant single mutation, present in about $40\text{-}60\%$ of cases; a constitutively active serine/threonine kinase that drives ERK signalling and confers a more aggressive phenotype.
2. RET/PTC rearrangement - second, enriched in radiation-exposed and paediatric tumours.
3. RAS - more linked to follicular-pattern thyroid tumours than classic PTC.
So the "most common" answer is BRAF V600E - Option A.
Disqualifying the rest with disease-association cues:
• RET as a germline POINT mutation → medullary carcinoma / MEN-2, a different tumour.
• MET → think hereditary papillary RENAL cell carcinoma, not thyroid.
• RAS → follicular carcinoma / follicular-variant PTC, lower frequency in classic PTC.
Final: BRAF V600E is the commonest mutation of papillary thyroid carcinoma.
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