RESUMO
Programmed death-1 (PD-1) negatively regulates the immune response. The aims of this study were to assess the association of two single nucleotide polymorphisms in the PD-1 gene, PD-1.5 (+7785 C/T-rs2227981) and PD-1.3 (+7146 G/A- rs11568821), with benign and malignant brain tumors. Patients with brain tumors (96 patients with benign and 56 with malignant brain tumors) and 150 healthy control individuals were included. PCR-RFLP was performed for genotyping. It was revealed that the genotype and allele frequencies of PD-1.5 C/T polymorphism were significantly different between all brain tumor patients and the control group. The frequencies of the CT genotype and T allele were higher in brain tumor patients. In contrast, the frequency of PD-1.3 G/A genotypes and alleles showed no significant difference between all brain tumor patients and controls. Patients were then divided into malignant and benign groups. The results revealed a significant difference in both patients groups compared with the controls only at PD-1.5 C/T position. Arlequin analysis showed the GC haplotype was the most frequent haplotype in the whole group of patients and controls, and the GT haplotype was significantly different between patient and control groups. In conclusion, we demonstrate that PD-1.5 C/T polymorphism, but not PD-1.3 G/A, is associated with brain tumors in Iranian patients.
