A pathology report describes a tumor showing 'loss of heterozygosity at 17p13.1'. This finding implicates loss of function of which tumor suppressor?
- A TP53 ✓
- B RB1
- C VHL
- D APC
Correct answer: A. TP53
Explanation
TP53, the guardian of the genome, maps to chromosome 17p13.1. Loss of heterozygosity (LOH) at this locus combined with a point mutation in the other allele leads to complete p53 inactivation per Knudson's two-hit hypothesis. RB1 is at 13q14, VHL at 3p25, and APC at 5q21. Identifying LOH at 17p13.1 is a key finding in colorectal cancer progression (Vogelstein model, adenoma-carcinoma sequence).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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