Vitamin D receptor polymorphisms associate with the efficacy and toxicity of radioiodine-131 therapy in patients with differentiated thyroid cancer.

Background: Radioiodine-131 (I-131) therapy is the common postoperative adjuvant therapy for differentiated thyroid cancer (DTC) However, methods to evaluate the efficacy and toxicity of I-131 on DTC are still lacking.

Objective: To evaluate the association between vitamin D receptor (VDR) gene polymorphisms and the efficacy and toxicity of I-131 in DTC patients.

Methods: A total of 256 DTC patients who received I-131 therapy were enrolled. The patients were divided into effective group and ineffective group. 4 single nucleotide polymorphisms (SNPs) (rs7975232, rs731236, rs1544410 and rs10735810) of VDR were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) Cell counting kit-8 (CCK-8) and flow cytometry were used to detect the proliferation and apoptosis of thyroid cancer cells.

Results: Patients in effective group had more CC genotype of rs7975232 and GG genotype of rs10735810 compared with patients in ineffective group They were also independent factors for influencing the efficacy of I-131. PTC-1 and FTC-133 cells transfected with CC genotype of rs7975232 showed lower proliferative activity and higher apoptosis rate after being treated with I-131 In addition, patients with CC genotype at rs7975232 had fewer adverse reactions after I-131 treatment.

Conclusions: VDR gene polymorphisms may be associated with the efficacy and toxicity of I-131 in DTC patients, which will help to personalize the treatment for patients.