The complexity of biological systems is often prohibitive in testing specific hypotheses from first physical principles. To circumvent these limitations we used biological data to inform a mathematical model of breast cancer cell motility. Using this in silico model we were able to accurately assess the influence of actin cytoskeletal architecture on the motility of a genetically modified breast cancer cell line. Furthermore, using the in silico model revealed a biological phenomenon that has not been previously described in live cell movement. Fusing biology and mathematics as presented here represents a new direction for biomedical research in which advances in each field synergistically drive discoveries in the other.