Cancer is not only activated by tyrosine kinase genes, but also by non-
tyrosine kinase genes, namely activated CDC42 kinase. Atypical non-
receptor tyrosine kinase ACK1 (activated CDC42 kinase 1) is widely
expressed and integrates and transmits signals from a variety of ligand-
activated receptor tyrosine kinases, including EGFR, HER2, and PDGFR1.