Pharmacological Basis of Breast Cancer Resistance to Therapies - An Overview

Breast Cancer (BC) is a molecular heterogeneous disease and patients with similar clinico-pathological characteristics often display different response to treatment. Cellular processes, including uncontrolled cell-cycle, constitutive activation of signalling pathways and alterations in DNA-repair mechanisms are the main altered features in breast cancer. These cellular processes play significant roles in the emergence of resistance to therapies. The introduction of target therapies and immunotherapy significantly improved the survival of breast cancer patients. The incorporation of novel biomarkers together with the introduction of new therapeutic options may help to overcome treatment resistance. Molecular profiling promises to help in refine personalized treatment decisions and catalyse the development of further strategies when resistances inevitably occurs. This review provides a summary of genetic and molecular aspects of resistance mechanisms to available treatments for BC patients, and its clinical implications.