We are conducting a pilot study of 12 thyroid cases of genomic characterization of thyroid cancer using tumor/non-tumor paired tissue – fresh-frozen and formalin-fixed paraffin embedded, plus blood samples, from a Ukrainian cohort of 12,000 individuals exposed to radioactive iodine as a child or adolescent following the Chernobyl accident, carrying out exome and RNA sequencing, SNPs and methylation analyses. This pilot study is in progress, and a larger study is being planned to identify genomic patterns specific to radiation in 300-400 thyroid tumors from those exposed to I-131 as a child or adolescent in Ukraine.