Due to the crucial role of HIF-1α and CXCR4/CXCL12 in the metastatic process of colorectal cancer, we determined CXCR4 and CXCR7 gene expression in human colon carcinomas and their modulation by hypoxia and HIF-1α in colon cancer cell lines. The gene discussed is CXCR4; the disease is colon carcinoma.