PTK6 and cancer: Enhanced expression in cancer cell lines of these tissue types promotes proliferation, survival, migration, and metastases.17–21 PTK6 copy number gain or amplification represents one mechanism by which PTK6 expression is increased in tumor cells; however, PTK6 protein expression in cancer is also regulated by transcriptional and post-transcriptional mechanisms, including HIF-1α-stimulated transcript expression and HSP90-mediated protein degradation.22,23