PXN and cancer: It has been shown that recognizing specific phosphorylated tyrosine residues on p130Cas and paxillin by SH2 domain of Crk and DOCK180 by SH3 domain of Crk will activate cell signaling pathway, which triggers cytoskeketal movement and cancer cell invasion and migration.25,26 Thus, increased expression of CrkII in CaexPA, MEC and AdCC are directly associated with enhanced invasive and metastatic properties of these tumors.