VHL and squamous cell carcinoma: To determine how cells from different tissue origins respond to hypoxia in terms of HIF levels and activities, we examined 5 6U-HBR carcinomas cell lines, namely, 786+VHL from renal cell adenocarcinoma, A549 from lung carcinoma, ME180 from epidermoid carcinoma in cervix, U251 from glioma, and HeLa from cervical adenocarcinoma.