PTK2 and neoplasm: As a paralogous homolog of FAK, proline-rich tyrosine kinase 2 (PYK2) displays a similar multi-domain organization and protein binding sites to FAK, forming a subfamily of adhesion kinases together with FAK that is crucial in regulating signaling networks involved in tumor growth and metastasis (Sulzmaier et al., 2014; Naser et al., 2018).