MAPK8 and neoplasm: Since JNK activity could be efficiently repressed by the second‐generation, ATP‐competitive, anthrapyrazolone JNK inhibitor CC‐401 (hereafter referred to as JNKi) in MDA231‐LM2 and SUM159‐LM1 cells (Fig EV1A), tumor‐bearing mice were treated with JNKi every third day, starting at day 5 post‐implantation (Fig 1G).