Preclinical investigations have shown that NPI‐2358 causes direct cytotoxicity to rapidly proliferating ECs and/or cancer cells by inducing apoptosis through cleavage of poly(ADP‐ribose) polymerase (PARP), activation of caspase‐3, caspase‐8, and caspase‐9, and triggering phosphorylation of the stress response protein JNK (c‐Jun N‐terminal kinase) 150. Here, MAPK8 is linked to cancer.