Single Nucleotide Polymorphism of rs1800247 in Promoter Region of Osteocalcin Gene in Patients with Medullary Thyroid Carcinoma

Medullary thyroid carcinoma is a malignant tumor originated from parafollicular cells. Osteocalcin (OC) is the most non-collagenous protein in bone and its gene is located on chromosome 1 (1q25-q31). Important polymorphism in promoter region of osteocalcin gene is located at 298nt (rs1800247), in which C base is converted to T base. In this study, to evaluate the presence of this polymorphism with existence of medullary thyroid carcinoma (MTC), the rs1800247 polymorphism in promoter region of osteocalcin was studied.

In a case-control study, we evaluated the single nucleotide polymorphism (SNP) of rs1800247 in osteocalcin gene promoter in 200 volunteers, including 100 cases and 100 controls, consist of 106 men and 94 women. The mean age was 35.0 ± 11.3 and 37.0 ± 13.8 years in patients and controls, respectively. Thyroid biopsies and pathology confirmation were considered as confirmation of the medullary thyroid carcinoma diagnosis. Genomic DNA was extracted from the leukocytes using the standard Salting Out/Proteinase K method. Polymorphism detection was performed by polymerase chain reaction-sequencing (PCR-sequencing) and direct DNA sequencing methods. Obtained results were statistically analyzed using logistic regression method. The confidence level considered at 95%.

In patients’ population, the genotype frequency was 7%, 48%, and 45% for CC, TT, and CT, respectively; these amounts were 8%, 55%, and 37% in controls, respectively. The frequency of C allele was 29.5% in patients 35.5% in controls; and the frequency of T allele frequency was 70.5%, and 64.5% in patients and controls, respectively. There was not any statistically significant difference between the groups in any of the cases.

There was no association between the single nucleotide polymorphism of rs1800247 in promoter region of osteocalcin gene in patients with medullary thyroid carcinoma compared with normal individuals. According to no difference between allelic and genotypic frequencies between patients and controls, the mentioned polymorphism is not suitable candidate for genetic diagnosis of medullary thyroid carcinoma.