MAPK7 and cancer: There has been significant interest in developing ERK5 inhibitorsto interrogate its role in cancer.11,12 Oxindole BIX02189(Figure 1; 1) was identified as a dual ERK5–MEK5 inhibitor.13 Subsequently, AX15836 (2), a potentand selective ERK5 inhibitor from the pyrimidodiazepinone series,was reported as a useful ERK5 probe14 andBAY-885 (3) was disclosed as a structurally differentiatedinhibitor.15