[DNA double-strand breaks repair capacity and risk of differentiated thyroid cancer: a case-control study]

Objective: To study the influencing factors of DNA double-strand breaks (DSB) repair capacity and relationship with differentiated thyroid cancer (DTC). Methods: A total of 140 patients with thyroid diseases admitted to the Henan Cancer Hospital from January 2020 to March 2020 were retrospectively analyzed, including 26 males and 114 females, aged from 18 to 78 years old. According to the pathological results, the patients were divided into DTC group (90 cases) and control group or benign thyroid nodules (BTN) group (50 cases). The DSB repair ability of peripheral blood T lymphocytes was measured by flow cytometry. The data of two groups were compared by Wilcoxon rank sum test to evaluate the relationship between DSB repair ability and the risk of DTC. According to the median repair ability of DSB in BTN group, the repair ability of DSB was divided into high and low categories, and the factors influencing the repair ability of DSB were analyzed by Logistic regression method. SPSS 22.0 software was used to analyze the data. Results: The DSB repair capacity was 27.87% in DTC group and 36.75% in BTN group, with significant difference (Z=-3.999,P<0.05). Logistic regression analysis suggested that patients with thyroid cancer had lower DSB repair capacity than patients without cancer (OR=2.245; 95%CI: 1.067-4.725; P=0.033), and patients with a history of radiation exposure had a reduced DSB repair capacity (OR=2.698; 95%CI: 1.271-5.725, P=0.010). Conclusion: The risk of DTC increases in patients with low DSB repair capacity. Radiation exposure is a risk factor for the reduction of DSB repair capacity.