More than 275 million people in the world are carriers of a heterozygous mutation of theCFTRgene, associated with cystic fibrosis, the most common autosomal recessive disease among Caucasians. Some recent studies assessed the association between carriers ofCFTRvariants and some pathologies, including cancer risk. The aim of this study is to analyze the landscape of germline pathogenic heterozygousCFTRvariants in patients with diagnosed malignant neoplasms. For the first time in Russia, we evaluated the frequency ofCFTRpathogenic variants by whole-genome sequencing in 1800 patients with cancer and compared this with frequencies ofCFTRvariants in the control group (1825 people) adjusted for age and 10,000 healthy individuals. In the issue, 47 out of 1800 patients (2.6%) were carriers ofCFTRpathogenic genetic variants: 0.028 (42/1525) (2.8%) among breast cancer patients, 0.017 (3/181) (1.7%) among colorectal cancer patients and 0.021 (2/94) (2.1%) among ovarian cancer patients. PathogenicCFTRvariants were found in 52/1825 cases (2.85%) in the control group and 221 (2.21%) in 10,000 healthy individuals. Based on the results of the comparison, there was no significant difference in the frequency and distribution of pathogenic variants of theCFTRgene, which is probably due to the study limitations. Obviously, additional studies are needed to assess the clinical significance of the heterozygous carriage ofCFTRpathogenic variants in the development of various pathologies in the future, particularly cancer.