Establishing the First Genetic Variant Registry for Breast and Ovarian Cancer in Colombia: Insights and Implications.

Genetic insights from diverse populations are key to advancing cancer detection, treatment, and prevention. Unlike other Latin American countries, Colombia lacks a centralized registry for germline and somatic mutations in breast and ovarian cancer. This study describes the country's first national variant registry, and the occurrence of recurrent mutations and potential founder effects in Colombia. To address this gap, we implemented the first capturing protocol using the REDCap system. In a group of 213 breast and/or ovarian cancer patients harboring genetic mutations, we collected genetic, clinical, and demographic data from 13 regional centers across Colombia. Statistical analyses assessed variant distribution and patient demographics. Among 229 identified variants (105 germline, 124 somatic), most were classified as pathogenic or likely pathogenic (72.4% germline, 87% somatic). BRCA1 and BRCA2 accounted for the majority of recurrent mutations. Germline recurrent variants (seen >3 times) were recorded for BRCA1 (77.7%; 21/27) and BRCA2 (22.3%; 6/27). Similarly, recurrent somatic variants were identified for BRCA1 (82.6%; 38/46) and BRCA2 (17.4%; 8/46). Notably, four recurrent variants were previously reported as founder mutations: BRCA1 c.1674del (14.3% germline and 23.7% somatic), BRCA1 c.3331_3334del (33.3% germline and 52.6% somatic), BRCA1 c.5123C>A (52.4% germline and 23.7% somatic), and BRCA2 c.2808_2811del (50% germline and 50% somatic). Most cases originated from the Andean region, highlighting regional disparities. This registry offers the first overview of genetic variants in Colombian breast and ovarian cancer patients. Recurrent and region-specific mutations highlight the need for population-focused data to guide targeted screening and personalized care strategies.