Assessment of vitamin D and VDR gene expression in colorectal cancer patients

Abstract

Background: Vitamin D insufficiency may increase risk and/or progression of cancer. Vitamin D acts through a nuclear receptor (VDR) which binding to vitamin D response elements causes changes in many genes expression. The aim: to assess the serum concentration of 25-hydroxycholecalciferol (25(OH)D3) and tissue VDR expression in colorectal cancer patients in relation to disease stage, tumor localization and disease progression. Material & Methods: The study group consisted of 39 patients with colorectal cancer (mean age 65,5±6,8 yrs, 23/16 male/female) and a control group consisted of 25 patients (mean age 51,0±6,9 yrs; 8/17 male/female) without gastrointestinal disease and without neoplasm. Serum level of 25(OH)D3 was measured by HPLC/UV. RNA was isolated from homogenized normal colonic mucosa and tumor tissue then RT-PCR was performed. Results: The mean serum concentration of 25(OH)D3 was lower in the colorectal cancer patients as compared to the control group. The difference was significantly lower only for the patients with the early stages of the disease (p<0.02) and for the patients with tumor present in rectum (p<0.03). Higher VDR expression in tumor tissue than in normal colonic mucosa was observed. For the patients with the early stages of the disease (stage A, B1, B2) higher expression of VDR as compared to the patients with advanced stages (stage C1, C2, D) was noticed. Moreover, VDR expression was higher in tumor tissue obtained from disease-free patients as compared to the patients with disease progression noted one-year-follow-up (p<0.04). Conclusion: Antitumor effect of vitamin D depends on VDR expression in tumor tissue.