Biology & Biochemistry of Cancer & Therapeutic Implications

Question 1

Which one of the following is not a general biochemical property of tumor cells?
A. increased glucose uptake
B. increased glutamine uptake
C. Increase isocitrate synthesis
D. Increase lactate production
E. Increased lipid synthesis

Answer 1

C. Increase isocitrate synthesis

Question 2

Activity of which one of the following is generally increased in tumor cells?
A. APC
B. HIF-alpha
C. RB
D. RP53
E. VHL

Answer 2

B. HIF-alpha

Tumors initially acquire their nutritional supply from the nearby existing vasculature. As the tumor expands, these vessels become incorporated, but they do not adequately meet the needs of the growing tumor. Hypoxia ensues, which results in the stabilization of the protein hypoxia-inducible factor-1α (HIF-1α).
Under hypoxic conditions, HIF-1α dimerizes with HIF-1β activate the transcription of the vascular endothelial growth factor (VEGF) and other angiogenic molecules, platelet-derived growth factor (PDGF) and transforming growth factor-α (TGF-α) which promote further tumor growth. Thus, HIF-1α functions as a master switch to induce expression of angiogenic and tumor growth factors.