Polymorphic Variants and Thyroid Disease, Kazakhstan

Thyroid tumors, variants in the RET and RAS signaling pathways, and DNA repair associated with fallout in Kazakhstan

Genetic factors, in addition to ionizing radiation exposure, may play a role in the risk of thyroid cancer. Thyroid nodules represent an intermediate endpoint related to thyroid cancer. Several polymorphisms potentially relevant to thyroid tumorigenesis were evaluated among individuals with high nodule prevalence. Thyroid nodules were detected in 907 persons who lived near the Semipalatinsk nuclear test site in Kazakhstan when they were children (1949-1960). We frequency matched (1:1) those without nodules (controls) to cases by ethnicity (Kazakh or Russian), gender, and age in 1998. Genomic DNA was analyzed, and results suggest that polymorphic variants in the RET proto-oncogene or RET-related genes may play a role in the etiology of thyroid nodules and possibly thyroid cancer. Further, we identified potential gene-radiation interaction with a polymorphism in XRCC1. XRCC1 is a gene that codes for a key base excision repair protein. .

Semipalatinsk Nuclear Test Site, Kazakhstan