"Study identified a nonsense mutation of PTPN4 with mutation ratio of 90.90% from 1 case of rectal cancer. Overexpression of PTPN4 suppressed the growth of colorectal cancer cells. PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and depresses the transcriptional activity of STAT3."xsd:string