Implication of <i>Mt-CYB</i> Gene Mutations in the Genetic Evolution of Breast Cancer in Chad

Background WHO reports in 2024 revealed that breast cancer affects women of all ages from puberty onward, with incidence increasing with age. Approximately 2.3 million new cases were recorded. In 2022, this disease caused 670,000 deaths worldwide. Low-penetrance genes, although not systematically associated with a high risk of breast cancer, appear to play an important role. These genes, frequently mutated in the general population, contribute significantly to breast cancer susceptibility, particularly when they interact with environmental factors or other genetic mutations. This study aims to evaluate the involvement of <i>MT-CYB</i> gene mutations in the progression of breast cancer among Chadian women. Methods We analyzed the variability of the <i>MT-CYB</i> gene in 43 patients using the PCR-sequencing technique. First, raw sequencing data were processed through the Mutation Surveyor software, which compares submitted chromatograms with the reference sequence. Next, we identified present mutations and assessed their potential impact on pathogenicity. Results Our findings highlight the potential role of the <i>MT-CYB</i> gene in the development of breast cancer in Chadian women. We identified 53 mutations, including 21 (39.62%) homozygous and 32 (60.37%) heterozygous mutations. Among them, 14 were already listed in the dbSNP database, while 39 were novel, with the majority found in cancerous tissues. Among these mutations, 69.81% (37/53) were non-synonymous substitutions, resulting in an amino acid change in 86.04% (37/43) of cases. Pathogenicity analysis revealed that 48.64% (18/37) were potentially deleterious, while 51.35% (19/37) were classified as neutral polymorphisms according to prediction software that considers protein structure. A detailed evaluation of the non-synonymous mutations showed that, of the 37 analyzed, 67.56% (25/37) were considered pathogenic, and 32.43% (12/37) were deemed benign. Conclusion These results highlight the crucial importance of prevention, early detection and genetic research to better understand and treat breast cancer.