Background/aim: Vitamin D receptor (VDR) expression has been shown to be upregulated in several tumors and is thought to represent an important endogenous response to tumor progression. Therefore, in order to evaluate the role of VDR-gene and of the 25(OH)-Vitamin D3 in thyroid cancer we analysed four polymorphisms in patients with thyroid cancer and healthy controls.
Patients and methods: Patients (n=136; 84 females and 52 males) with differentiated thyroid cancer (follicular or papillary) and healthy controls (n=210; 99 females and 111 males) were genotyped for the ApaI (rs7975232), BsmI (rs154410), TaqI (rs731236) and Fok I (rs10735820) polymorphisms within the VDR-gene in the German population by the PCR-RFLP method. In addition, the 25(OH)-Vitamin D3 serum levels in patients were measured using RIA.
Results: The genotype aa of the ApaI polymorphism was significantly less frequent (5.1 vs 18.6%; P<0.0003) while heterozygosity was more frequent in patients than in controls (62.5 vs 45.2%). No association between BsmI, TaqI and Fok I and thyroid cancer was observed. Furthermore, 74% of the patients showed low serum levels of 25(OH)-Vitamin D3 (<20 ng/ml).
Conclusion: Both genotypes (Apa I polymorphism) within the VDR-gene and low serum levels of 25(OH)-Vitamin D3 appear to be associated with differentiated thyroid cancer Germans. Nevertheless, additional work is necessary to define the extended genotype of VDR and other loci of the vitamin D system and their impact on the 25(OH)-Vitamin D3 levels as well as their possible clinical applications.
03 - 07 May 2008
European Society of Endocrinology