Radioiodine therapy accelerates apoptosis in peripheral blood lymphocytes of patients with differentiated thyroid cancer.

Both apoptosis and micronuclei formation reflect cytogenetic damage in cells and could contribute to cell homeostasis. The aim of this study was to evaluate apoptosis in peripheral blood lymphocytes (PBLs) of patients with differentiated thyroid cancer (DTC) before and after 131-iodine (131-I)-therapy and its correlation with micronuclei (MN) frequency. The study population included 18 DTC patients and 18 healthy donors. Apoptotic cells were detected using the Annexin V-FITC/7-AAD kit and MN frequency by cytokinesis-block MN assay. The difference between early apoptosis in PBLs of DTC patients before therapy and controls (9.88 ± 4.99% vs. 6.64 ± 2.07%, p = 0.003) was significant, as well as between early apoptosis in PBLs of DTC patients before and after 131-I-therapy (9.88 ± 4.99% vs. 13.53 ± 6.57%, p = 0.008). The MN frequency and early apoptosis in PBLs of DTC patients was positively correlated before (r = 0.540, p= 0.021) and after 131-I-therapy (r = 0.585, p= 0.014). Thyroid cancer patients had a significantly increased early apoptosis in PBLs, which further increased after 131-I-therapy in association with MN frequency.