Vitamin D receptor gene polymorphisms in patients with thyroid cancer

The association between vitamin D receptor (VDR) gene polymorphisms and some diseases such as colorectal cancer, breast cancer, osteoporosis and psoriasis has been extensively investigated during the past few years. This research was performed not only because of the role of vitamin D as an anticancer agent, but also because of the suppressing action of vitamin D on TSH, the major regulator of thyroid cell growth. In this case-control study, comprising 71 thyroid cancer patients and 82 healthy population controls, we investigated the association between altered thyroid cancer risk with four polymorphisms located at the 3' end of the VDR gene detectable by ApaI, TaqI, Tru9 and BsmI restriction enzymes and with a start codon polymorphism located at the 5' end characterized by restriction enzyme FokI. The individual genetic pattern for VDR was evaluated by DNA extraction followed by PCR amplification of the VDR gene and the digestion with the restriction enzymes. For the effect of existence of the mentioned polymorphisms and thyroid cancer the odds ratio and 95% CI were calculated. All the odds ratios were within their CI, representing no relationship between these polymorphisms and risk of thyroid cancer. These observations suggest that VDR gene polymorphisms may not commonly contribute to the risk of thyroid cancer.