Cancer Biochemistry and Tumor Markers (Oncogenes, Warburg, Oncometabolites, Apoptosis) MCQs

Biochemistry · 17 free questions with answers & explanations.

1. The Warburg effect in cancer cells is characterised by preferential aerobic glycolysis even in the presence of oxygen. Which enzyme's upregulation is primarily responsible for the shift to lactate production rather than pyruvate entering the TCA cycle?
2. IDH1/IDH2 mutations found in glioma and AML produce the oncometabolite 2-hydroxyglutarate (2-HG). What is the primary mechanism by which 2-HG drives tumorigenesis?
3. AFP (alpha-fetoprotein) is elevated in which two malignancies where it is used as a tumor marker, and what is its molecular weight?
4. In the intrinsic pathway of apoptosis, cytochrome c released from mitochondria binds to which adaptor protein to form the apoptosome, leading to activation of which initiator caspase?
5. The Warburg effect in cancer cells describes aerobic glycolysis. Despite adequate oxygen, cancer cells preferentially convert pyruvate to lactate. What is the PRIMARY biochemical advantage of this metabolic reprogramming?
6. IDH1/IDH2 mutations in gliomas and AML produce 2-hydroxyglutarate (2-HG). How does 2-HG act as an oncometabolite?
7. During the intrinsic pathway of apoptosis, Bax/Bak form pores in the outer mitochondrial membrane. What is the DIRECT consequence that commits the cell to apoptosis?
8. PSA (prostate-specific antigen) is used as a tumor marker for prostate cancer. What is the biochemical nature of PSA and why can it be elevated in benign conditions?
9. Cancer cells preferentially use aerobic glycolysis rather than oxidative phosphorylation even in the presence of adequate oxygen (Warburg effect). Which of the following best explains the metabolic advantage of this strategy for rapidly proliferating cells?
10. IDH1/IDH2 mutations in gliomas and AML produce the oncometabolite 2-hydroxyglutarate (2-HG). What is the mechanism by which 2-HG promotes oncogenesis?
11. Cytochrome c release from mitochondria during intrinsic apoptosis leads to formation of the apoptosome. Which protein does cytochrome c bind to form this complex?
12. Alpha-fetoprotein (AFP) is elevated in hepatocellular carcinoma. Which other tumour typically produces very high AFP levels, and what is the biochemical basis for AFP production?
13. The Warburg effect refers to the observation that cancer cells preferentially use aerobic glycolysis even in the presence of oxygen. Which mitochondrial enzyme is characteristically DOWNREGULATED to favour this metabolic shift?
14. 2-Hydroxyglutarate (2-HG) is an oncometabolite produced by gain-of-function mutations in IDH1/IDH2. Which PRIMARY mechanism drives tumorigenesis?
15. Bcl-2 family proteins regulate apoptosis at the mitochondrial level. In the intrinsic pathway, cytochrome c release from the mitochondrial intermembrane space is facilitated by:
16. CEA (carcinoembryonic antigen) is elevated in colorectal cancer but is NOT used for diagnosis. Its MOST appropriate clinical role is:
17. The Philadelphia chromosome translocation t(9;22) creates a BCR-ABL fusion protein. The resulting constitutively active enzyme is BEST described as a: