CFTR and breast cancer: The distribution of the identified CFTR pathogenic variants, depending on the localization of the primary tumor, is as follows: in the cohort of BC patients, the frequency of pathogenic variants was 0.028 (42/1525) (2.8%), in CRC patients 0.017 (3/181) (1.7%) and ovarian cancer (OC) 0.021 (2/94) (2.1%).