Many studies have established critical roles for HIF-1α in tumor cell survival and malignancy: i) HIF-1α is involved in repression of hypoxia-induced apoptosis in HCT116 and RKO cells in vitro[26]; ii) HIF-1α is required for VEGF-deficient tumor cell survival under hypoxic conditions in vivo[20], and iii) HIF-1α supports spheroid formation [18]. This evidence concerns the gene HIF1A and neoplasm.