STAT3 and neoplasm: However, other modes of action of PTPRK, such as dephosphorylating other signaling factors like β-catenin, EGFR, or STAT3 (Xu et al., 2005; Novellino et al., 2008; Chen et al., 2015), or cell junction proteins (Fearnley et al., 2019), may also contribute to its tumor-suppressive function.