Germline genetic mutations in high-risk patients for breast cancer: profile of a group in the city of Florianopolis, Santa Catarina

ABSTRACT

To analyze the occurrence of genetic mutations in a sample of patients with high risk of breast cancer in Florianopolis/ SC from December 1st, 2021, to January 31, 2022. Methods: An observational, descriptive and retrospective study carried out through data collection of a preexisting database. A total of 194 tests were analyzed. Of these, 192 met the inclusion criteria and composed the final sample of 205 genes. Data were classified and reported the frequency and percentage of the variables gene and presence or absence of mutation. Results: Mean age of the analyzed patients was 52.3 years, and most underwent the test due to personal history of breast cancer (80%). Clinical significance classification showed that, of the 192 gene panels, 62% were variants of uncertain significance; 14% were pathogenic; and 24%, negative. Of the 205 mutations, the most prevalent genes were ATM 8.7%, MUTYH 5.8%, POLE 5.8%, BRCA2 4.8%, MSH6 4.8% and RECQL4 4.8%. Of the pathogenic tests regarding genetic predisposition to cancer (n=38/14.1%), the most common mutations were MUTYH (23%) and BRCA1 (15%), with mean age of 52 years (±14.3). In variants of uncertain significance panels (n=168/62%) the frequency rates were ATM (7.7%), POLE (7.1%) and MSH6 (5.9%) genes. The high penetrance genes were present in 18% of the genetic predisposition to cancer panels. Of those with positive family history (n=40), 19% of the genes were pathogenic, 53% were variants of uncertain significance; and 26% were negative. Furthermore, in patients with pathogenic mutations and positive family history (n=11), the most common mutations were in BRCA1 (27%) and BRCA2 (27%). Of the patients who tested due to personal history (n=152), 64% of the genes presented variants of uncertain significance, 13% were pathogenic and 22% were negative.