A 33-year-old man with a family history of hemangioblastomas presents with hematuria. Vital signs show BP 145/92, HR 88, RR 16, temp 37°C, SpO2 98%. CT abdomen reveals a 4-cm clear cell renal cell carcinoma with increased vascularity; hemoglobin 10.2 g/dL. He denies constitutional symptoms. Genetic testing confirms VHL gene loss. Which downstream molecular effect most directly explains this tumor's marked angiogenesis?
- A)Accumulation of hypoxia inducible factor with increased VEGF transcriptionGABARITO
- B)Suppression of beta catenin signaling
- C)Impaired homologous recombination repair
- D)Increased degradation of hypoxia inducible factor
- E)Reduced expression of glucose transporter proteins
Explicação
VHL normally targets hypoxia inducible factor for degradation. When VHL is lost, HIF accumulates and upregulates VEGF and other hypoxia response genes, promoting angiogenesis and the highly vascular phenotype of clear cell renal cell carcinoma and hemangioblas... Ver explicação completa e trilha adaptativa →