MAPK9 and cancer: Mitogen-activated protein kinase kinase kinase 2 / MEKK2. Integrates stress and mitogenic signals to the activation of NF-kB, JNKs, p38, and ERK5 pathways. Directly phosphorylates and activates stress-activated protein kinases (SAPK/JNKs) and I-kappa-B kinases (IKKs). Promotes motility and invasiveness in cancer cells, in part through control of focal adhesion stability [136].