Gastric Cancer — SCE Medical Oncology MCQ
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Correct answer: B — PIK3CA mutation, CpG-island hypermethylation and JAK2–PD-L1–PD-L2 amplification
Explanation lettering: C = shown as A · A = shown as B · B = shown as C · E = shown as D · D = shown as E
A is correct. EBV-positive gastric cancer is enriched for PIK3CA mutation, marked CpG-island methylation and amplification of 9p24.1 containing JAK2, CD274 and PDCD1LG2. MLH1 silencing and very high mutation burden characterise the MSI subgroup. CDH1 and RHOA alterations typify the genomically stable subgroup, while TP53 mutation, aneuploidy and receptor-tyrosine-kinase amplification typify chromosomal instability. APC-driven WNT biology is more characteristic of colorectal tumorigenesis. EBV status is biologically informative but does not by itself replace licensed biomarker and commissioning criteria for immunotherapy.
Reference: TCGA molecular characterisation of gastric adenocarcinoma: https://pubmed.ncbi.nlm.nih.gov/25079317/