The mRNA levels of mitogen-activated protein kinase (MAPK) signaling pathway components have been shown to be significantly increased in the kidney of diabetic patients compared to healthy population [44], and reduced levels of p38 MAPK signaling have been found to be associated with protection against renal injury and this signaling pathway plays a distinct pathogenic role in the progression of DN [45]. This evidence concerns the gene WNK2 and liver dysplastic nodule.