PTK6 and cancer: Protein Tyrosine Kinase 6 (PTK6) encodes a cytoplasmic nonreceptor protein kinase, implicated in processes of proliferation, apoptosis, migration, and invasion in cancer cells (Harvey and Crompton, 2004; Shen et al., 2008; Xiang et al., 2008; Harvey et al., 2009; Locatelli et al., 2012; Park et al., 2015).