PTPN3 and malignant colon neoplasm: Because levels of p-p38γ protein expression are associated with those of its substrate protein tyrosine phosphatase H1 phosphorylation (p-PTPH1) in K-Ras MT, but not WT, colon cancer cells [22], we next examined if p38γ may phosphorylate Hsp90 thereby increasing its chaperone activity toward MT K-Ras.