Breast cancer is a malignant tumor that starts in the cells of the breast. A malignant tumor is a group of cancer cells that can grow into (invade) surrounding tissues or spread (metastasize) to distant areas of the body. Significant advancement has been made recently in delineating the cellular processes and signaling pathways involved in breast cancer. Cross-communication between different pathways allows cells to identify and respond appropriately to the extracellular environment. Cancer development is a gradual and complex process resulting from any disruption in these pathways. Several integrated signaling pathways are involved in breast cancer as they subsequently impact cellular responses such as cell survival, proliferation, migration, differentiation, and apoptosis