Genetic predisposition to differentiated thyroid cancer in the Polish population

INTRODUCTION Genome sequencing technologies reveal molecular mechanisms of differentiated thyroid cancer (DTC). Unlike somatic mutation analysis from thyroidectomy samples, germline mutations showing genetic susceptibility to DTC are less understood. OBJECTIVES The study aimed to assess the prevalence of germline mutations predisposing to DTC in a cohort of Polish individuals based on their whole genome sequencing data. PATIENTS AND METHODS We analyzed sequencing data from 1076 unrelated individuals totaling over 1018 billion read pairs and yielding an average 35.26 x read depth per genome, released openly for academic and clinical research as the Thousand Polish Genomes database (https://1000polishgenomes.com). The list of genes chosen for further analysis was based on the review of previous studies. RESULTS The cohort contained 104 variants located within the coding and noncoding DNA sequences of 90 genes selected by ClinVar classification as pathogenic and potentially pathogenic. The frequency of variants in the Polish cohort was compared with the frequency estimated for the non -Finnish European population obtained from the gnomAD database (gnomad.broadinstitute.org). Significant differences in variant frequency were found for the APC, ARSB, ATM, BRCA1, CHEK2, DICER1, GPD1L, INSR, KCNJ10, MYH9, PALB2, PLCB1, PLEKHG5, PTEN, RET, SEC23B, SERPINA1, SLC26A4, SMAD3, STK11, TERT, TOE1, and WRN genes. CONCLUSIONS Even though the Polish population is genetically similar to the other European populations, there are significant differences in variant frequencies contributing to the disease development and progression, such as those in the RET, CHEK2, BRCA1, SLC26A4, or TERT genes. Further studies are needed to identify genomic variants associated directly with DTC.