Genetic Counseling, Polymorphisms and Breast Cancer

Breast cancer, a highly penetrant hereditary disorder, is the most common cancer in women worldwide. Approximately 10% of breast cancer cases are hereditary and 15% of patients with invasive breast cancer have a first-degree relative with the same disorder. Genetic counseling has become an important tool of the health care system providing information and support to families at risk of a genetic disorder. Oncology research teams have designed breast cancer screening guidelines for highrisk patients. Along the past decade, several genes have been identified as genetically related to breast cancer inheritance. BRCA1 and BRCA2 are considered the most important genes related to inheritance predisposition of breast cancer, along with PTEN and TP53 [1]. The BRCA1 and BRCA2 structures are different but their functions are interconnected and related to DNA repair. The susceptibility of breast cancer for patients with the BRCA1 mutation is up to 87% for older women. Another gene, TP53, codes for a protein that acts as the guardian of the genome, binds to DNA in order to perform transcriptional regulatory functions, regulation of the cell cycle and apoptosis among other functions. According to genetic counseling and epidemiologic studies, the risk of developing cancer for patients with TP53 polymorphisms is 90%. Regarding the gene PTEN, germline mutations increases the risk of breast cancer and about 80% of patients with breast cancer carry germline mutations in the gene. PTEN is an oncogene and codes for a protein with phosphatase activity, related to the regulation of cell cycle, controlling cells growth and able to promote cell cycle arrest. Currently, genetic counseling endeavor to identify patients at risk of genetic anomalies, study family history and inheritance patterns, calculate risks of recurrence, and provide information regarding testing and treatment procedures. Therefore, breast cancer patients and their families are presented with possibilities of screening for BRCA1, BRCA2, TP53, and PTEN mutations, and preventive care such as chemoprevention and prophylactic surgery.