The effect of TP53 and P21 gene polymorphisms on papillary thyroid carcinoma susceptibility and clinical/pathological features

Papillary thyroid cancer (PTC) is the most common thyroid malignancy. Genetic polymorphisms of the TP53 and P21 genes are the candidate variants in various cancers development. This study investigated whether the polymorphisms in TP53 (rs1042522) and P21 (rs1059234 and rs1801270) affect the risk of PTC and whether such the genotype of these polymorphisms is associated with pathological and clinical characteristics of PTC. A case-control study was conducted with 286 Iranian people, including 131 PTC cases and 155 healthy controls. The genetic polymorphisms were investigated by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Our results suggested that TP53-rs1042522 CC genotype was significantly associated with protection against PTC, in the dominant, recessive and allelic models (OR = 0.4, 95%CI: 0.2-0.8, P = .008; OR = 0.5, 95%CI: 0.3-0.9, P = .01; OR = 0.6, 95%CI: 0.4-0.8, P = .002, respectively). The rs1042522 was associated with PTC patients with tumor size greater than 1 cm in dominant and recessive models (OR = 0.2, 95%CI = 0.04-0.9, P = .04 and OR = 0.3, 95%CI = 0.1-0.7, P = .009, respectively) and was associated with vascular invasion in dominant model (OR = 0.3, 95%CI = 0.1-0.7, P = .01). No correlation was identified between P21 rs1059234 and rs1801270 polymorphisms and risk of PTC and pathological and clinical characteristics of PTC. Genetic variations in rs1042522 might alter the PTC risk, which could affect tumor size and cause lower incidence of vascular invasion in PTC cases. This was the first report suggesting that no correlation was found between P21 rs1059234 and rs1801270 polymorphisms and PTC risk. Thus, more studies with a larger population size and different ethnic groups and functional assays are needed to confirm our results.