Consistent with this, elevated expression of HIF-1α and HIF-2α protein has been observed in a broad array of human cancer cell types in the absence of hypoxia, and we have previously reported and confirmed here that whereas nonmalignant cells do not express HIFs under normoxic conditions, colon cancer cells coexpress HIF-1α and HIF-2α under these conditions [5]. This evidence concerns the gene HIF1A and malignant colon neoplasm.