MAPK8 and cancer: While DUSP4 and DUSP16 can bind to all three MAPKs, they preferentially inactivate JNK.11, 17 Recent reports showed that DUSP4 or DUSP16 inhibits JNK activation, thereby reducing apoptosis and promoting cancer chemoresistance.18, 19 Another report indicated that the JNK phosphatase M3/6, also known as DUSP8, is inactivated by heat shock at 45 °C.15