DUSP22 and inflammatory myofibroblastic tumor: Since the tumor suppressive role of DUSP22 has been proposed [32], it is intriguing to consider whether UST-DUSP22 possesses a dominant negative effect against wild-type DUSP22. It is currently unknown whether spindle cell proliferation in this case is related to the findings observed in ALK-positive tumors such as inflammatory myofibroblastic tumor (Figure 3B).