VHL and neoplasm: A comparison was made between tumors derived from 786-O cells expressing VHL with inactivated HIF1α degradation and tumors derived from 786-O cells expressing VHL with intact HIF1α degradation but inactivated collagen/fibronectin interaction; it indicated that the elevation of the angiogenic growth factor VEGF by stabilized HIF1α is not sufficient to generate the highly vascular tumor phenotype.