Probable tyrosine protein-kinase, which has strong transforming capabilities on a variety of cell lines. When overexpressed, it can also induce tumor cell invasion as well as metastasis in distant organs. May act by activating both MAP kinase and phosphatidylinositol 3'-kinases (PI3K) pathways (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Widely expressed. Highly expressed in brain, placenta and prostate. Expressed in tumor cells such as hepatoma cells L-02, cervix carcinoma cells HeLa, ovary cancer cells Ho8910 and chronic myelogenous leukemia cells K-562, but not in other tumor cells such as epidermoid carcinoma (A-431). Undetectable in most normal lung tissues, widely expressed in lung cancers. Belongs to the protein kinase superfamily. Tyr protein kinase family.