Multiple Mutation Detection for Risk Assessment in Patients with Breast Cancer by Using Next-Generation Sequencing

Objective. Breast cancer is recognized as the most common cause of malignancy and cancer death worldwide; however, mutations in the cancer-related BRCA genes are detected in only 2-3% of patients with breast cancer. Because next-generation sequencing technology allows concurrent sequencing of numerous target genes, diverse cancer-susceptibility genes are now being evaluated, although their significance in clinical practice remains unclear. Methods. In this study, we developed a sequencing panel containing the genes BRCA1, BRCA2, TP53, PIK3CA, ERBB2 (Her2), and PTEN, which are all associated with cancer risk in patients, and we enrolled 60 patients with breast cancer. Results. Germline mutations were found to be carried by nine patients (15%): 3 in BRCA1, 5 in BRCA2, and 1 in TP53. The patients harboring these mutations are considered to face a high risk of developing malignant tumors, and cancer screening is thus recommended for the patients. Conclusion. This study demonstrates the feasibility of using Ion Torrent sequencing technology for reliably detecting gene mutations in clinical practice for guiding individualized drug therapy or combination therapies for breast cancer.