BTK and colorectal cancer: However, this positive interaction is dependent on CDC73 tyrosine dephosphorylation by the phosphatase SHP2 (ref. 47) and recent evidence suggests that CDC73 can repress WNT signalling in colorectal cancer cells and B-cells in response to activation of BTK (Bruton's Tyrosine kinase)26, a kinase that has been proposed to activate PKA48.