Cancer Biochemistry and Clinical Correlation MCQs

Biochemistry · 6 free questions with answers & explanations.

1. The Warburg effect in cancer cells describes aerobic glycolysis — glucose is converted to lactate even in the presence of oxygen. The metabolic advantage this provides to proliferating tumour cells (beyond ATP generation) is primarily:
2. Alpha-fetoprotein (AFP) is elevated in hepatocellular carcinoma and non-seminomatous germ cell tumours. The biochemical basis for AFP re-expression in HCC is:
3. Telomerase is reactivated in ~90% of malignant tumours. The biochemical mechanism by which telomere shortening without telomerase causes senescence/apoptosis, and the protein that detects critically short telomeres as 'DNA damage', is:
4. IDH1 and IDH2 mutations are found in >70% of low-grade gliomas and secondary glioblastomas. Wild-type IDH catalyses isocitrate → alpha-ketoglutarate (α-KG) in the TCA cycle. Mutant IDH (neomorphic activity) produces an oncometabolite that inhibits alpha-KG-dependent dioxygenases. This oncometabolite is:
5. Prostate-specific antigen (PSA) is a kallikrein-related serine protease. In prostate cancer, PSA is used as a tumour marker. PSA exists in two forms: free PSA and complexed PSA (bound to alpha-1-antichymotrypsin). The clinical utility of the free/total PSA ratio is:
6. BRCA1 and BRCA2 proteins are essential for homologous recombination (HR) repair of double-strand breaks. BRCA2 functions by loading which protein onto single-stranded DNA coated with RPA at DSB resection tails, initiating strand invasion of the sister chromatid?