Our previous study showed that HIF-1α protein expression is correlated with MDR1/P-gp expression in colon carcinoma tissue and a colon cancer cell line, and mRNA expression levels of HIF-1α and MDR1 are significantly higher in the same type of cells in hypoxic conditions than in normoxic conditions [12]. This evidence concerns the gene ABCB1 and malignant colon neoplasm.