Vitamin D Status and VDR Polymorphisms as Prognostic Factors in Differentiated Thyroid Carcinoma

Abstract

Background/Aim: Vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms are involved in a variety of biological processes including cell proliferation, apoptosis, and adhesion in malignant tumors. This study investigated whether vitamin D levels and genetic variations of VDR are risk factors for thyroid cancer. Patients and Methods: Patients who underwent surgery for differentiated thyroid carcinoma (n=113) and those with benign thyroid pathology (n=150) were genotyped for VDR gene polymorphisms (ApaI, TaqI, FokI, and BsmI) and their 25(OH)D levels were simultaneously measured. Demographic data and histopathologic reports were also acquired for all patients. Results: Vitamin D levels were significantly lower in the thyroid cancer group (p=0.03). FokI and TaqI polymorphisms were more frequent in the thyroid cancer patients (p<0.001). Compared to control, the proportion of the FokI Ff genotype was increased (p<0.0006) and the proportion of the TaqI Tt genotype was also higher among patients with thyroid cancer (p<0.0001). The Ff genotype of FokI was also associated with multifocality, invasive pattern, and risk for local metastasis. Conclusion: The VDR gene polymorphism FokI may be associated with the risk of thyroid cancer and its more aggressive forms.

Vitamin D-Related Genes and Thyroid Cancer—A Systematic Review

“…Of these, 33 were excluded for different reasons, as shown in Figure 3 . Ten studies met the inclusion criteria and are presented below [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

“…As expected, most of these studies (all but one) analyzed patients with a diagnosis of DTC. Only in one study were MTC patients enrolled, while there are no data about the anaplastic thyroid cancer [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Detailed characteristics of the studies included are presented in Table 1 .…”

“…In the latest study of the role of VDR polymorphism in the development of DTC, again a set of four SNPs was analyzed: rs2228570, rs7975232, rs1544410, and rs731236. The authors showed a potential predisposing role of Ff and FF genotypes of rs2228570 SNP and Tt heterozygote of rs731236 SNP in thyroid cancer pathogenesis [ 41 ].…”

“…A total of seven studies assessing VDR SNPs in thyroid cancer were found. Six different SNPs were involved: rs2228570, rs7975232, rs1544410, rs731236, rs757343, and rs11568820 [ 32 , 33 , 36 , 37 , 39 , 40 , 41 ]. In the case of one study, genotype and allele frequencies were not available [ 36 ].…”

“…Moreover, in the case of two SNPs, rs757343 and rs11568820, the number of studies presenting results was too low (two and one, respectively) [ 32 , 36 , 39 ]. Therefore, finally five different papers were included in the meta-analysis, with data on four different VDR SNPs (rs2228570, rs7975232, rs1544410, rs731236) [ 32 , 33 , 37 , 40 , 41 ].…”