MAPK8 and neoplasm: JNK activity in the liver has been linked to cancer, fibrosis and steatosis.17, 26 Consistent with this raised level of JNK activity in tumours, a modest but significant increase in the mRNA levels of MKK7 (mitogen-activated protein kinase kinase 7), a kinase known to activate JNK signalling in the liver, was seen (Figure 6d).17, 27 No significant effect was seen with the related kinase MKK4, although some RelA T505A tumour samples did display higher levels (Figure 6e).