Diagnostic, Prognostic and Predictive Factors of Response in the Era of Precision Oncology in Breast Cancer

Book excerpt: In the last couple of decades, the study of the cancer genome and the progressive implementation of next-generation sequencing platforms have provided the Scientific and Oncology communities with a multitude of data, technologies, diagnostic, prognostic, and predictive tools that have been revolutionizing the way we can study, diagnose and treat cancer, including breast tumors. For example, genomic tests can now refine the prognosis of early-stage breast cancer patients beyond standard clinicopathological features and help guide escalated or de-escalated treatment choices. The identification of the molecular intrinsic subtypes might also be helpful in guiding treatment choices in advanced hormone receptor-positive disease. The identification of germline mutations in BRCA1 or BRCA2 has led to the development and introduction of PARP inhibitors for the treatment of advanced and early-stage breast cancer, along with personalized follow-up and prophylactic surgical procedures for patients with or without cancer, carrying such mutations.