WNK2 and progressive multifocal leukoencephalopathy: JCPyV can activate cellular pathways, including the mitogen-activated protein kinase, extracellular signal-regulated kinase (MAPK/ERK) pathway [80,81,82,83] and the phosphoinositide 3-kinase/AKT signaling pathway [84,85] that can influence the expression of the FOX TF family, which in turn, may benefit viral transcription, as there are more TFBS in block “c” of the NCCR, isolated from PML patients (Figure 4).