Given that the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway also plays an important role in the functionality of tumor-infiltrating MDSCs [19], and the activation of ERK impairs the catalytic activity of AMPK [35], we also assessed the level of pERK and found that potassium significantly increased the level of the phosphorylated form of the kinase (Figure 4K,M), which agrees with previous reports indicating that potassium increases the ERK signaling pathways in different types of cells [36,37]. This evidence concerns the gene WNK2 and neoplasm.