Thus, during the early stage of breast cancer, major alterations to the actin cytoskeleton could control signaling pathways through distinct mechanisms: an increase in F-actin assembly would induce signaling pathways, such as MRTF-A–SRF, while actomyosin activity would trigger the mechanical induction of signaling components, such as ERK and SRC, highlighting the key contribution of actin cytoskeleton regulation to carcinogenesis. This evidence concerns the gene MRTFA and breast cancer.