The importance of immune effector cells to the therapeutic efficacy and the aforementioned hypotheses are corroborated by the Zeng group’s previous findings, which showed that anti-PRL-3 antibodies have no therapeutic activity in immunocompromised SCID mice or in vitro against PRL-3-expressing cancer cells where no effector cells are present (2, 13). Here, PTP4A3 is linked to cancer.