In contrast to these publications, several other studies that investigated the role of ERK were unable to demonstrate its activation, but reported activation of JNK, p38 MAPK and/or Akt/PI3K, in respectively, gastic cancer [49], extrahepatic cholangiacarcinoma [46], retinoblastoma [56] or gall bladder cancer [48]. Here, MAPK8 is linked to retinoblastoma.