As the upstream kinase of c-jun (another important component of AP-1), JNK is able to activate AP-1, and the activation of AP-1 by JNK is closely related with JNK’s function on regulation of various cellular reaction including cancer cell migration and invasion [22]; however, IL-1β-induced AP-1 activation in both AGS and MKN-45 cells was not inhibited by JNK siRNA nor JNK inhibitor SP600125 neither (Figure 5E). Here, MAPK8 is linked to cancer.