Aberrant expressions of HOX genes in colorectal and hepatocellular carcinomas.

HOX genes are known as master regulator genes which give cells positional information in embryogenesis. In this study, we compared the expression patterns of 39 HOX genes among human colorectal carcinomas from the right large intestine (cecum, ascending and transverse colon), those from the left large intestine (discending and sigmoid colon, and rectum) and hepatocellular carcinoma. The expression levels of each HOX gene were quantified by analysis based on the real-time RT-PCR. The expression patterns of HOX genes in colorectal and hepatocellular carcinoma tissues differed from those in their normal or non-cancerous tissues. Between the tumor tissues in the right-side large intestine and those in the left-side, different HOX genes were expressed in association with cancer. Further, the expression levels of HOXD8 in liver-metastatic tissues of colorectal carcinomas were as low as in non-cancerous liver tissues, and were significantly lower than those in the primary tissues. These results suggest that dysregulated expressions of HOX genes play an important role in carcinogenesis and malignant progression of colorectal and hepatocellular carcinomas.