The loss of function of the VHL protein in renal cell carcinoma is mediated by which of the following?
A. Bcl-2Answer B
Hypoxia inducible factors are transcription factors that respond to a decrease in oxygen levels on the cellular environment. Inactivation of the VHL protein leads to upregulation of HIF-2 alpha, which in turn leads to upregulation of VEGF, erythropoietin and PEGF. VEGF binds to a tyrosine kinase enzyme (VEGFR-2) on endothelial cells promoting tumour angiogenesis.