Vitamin D receptor expression is associated with colon cancer in ulcerative colitis

Since the 1970s, it has been well known that long-standing ulcerative colitis (UC) disposes to the development of colorectal adenocarcinoma (CRC). To date, CRC associated with UC is thought to arise along a pathway of dysplasia, however, primary factors for developing of UC-related dysplasia and cancer are unclear. Vitamin D, which works through binding the vitamin D receptor (VDR) has an important role in cancer progression and immune response. In this study, we investigated the impact of VDR expression on UC as well as colon cancer. We examined retrospectively the expression of VDR in extraction specimens of UC (n=124) patients by immunohistochemistry. We counted VDR positive cells in at least 10 fields in each case to evaluate the frequency of VDR positive cells in ductal epithelium. In addition, effect of VDR expression on inflammation was analyzed. On a normal mucosa, the expression of VDR was recognized in 58.8% of ductal cells. In UC patient, the expression of VDR was considerably decreased compared to normal mucosa, VDR positive rate was only 3.4+/-9.0%. Importantly, dysplasia and UC-CRC patients showed lower rate of VDR expression compared to non-colon cancer patients, whose expression rates were 0.6+/-1.3% and 3.8+/-10%, respectively. Moreover, long-term UC patients (more than ten years) who were at high-risk of developing CRC showed significantly lower VDR expression than short-term patients. We did not detect direct association of VDR expression with inflammation and clinical stage of UC. These findings suggested that correlation seems to exist between the level of VDR expression and carcinogenesis in UC. VDR could be a possible marker to detect dysplasia and cancer in ulcerative colitis.