ASIC4 and metastatic melanoma: To evaluate the physiological relevance of the ASICs and ENaC channels in melanoma, we performed the analysis of the TCGA database and revealed that expression of ASIC2, ASIC3, ASIC4, α- and γ-ENaC but not of ASIC1 mRNA was significantly down-regulated in samples of patients with primary and metastatic melanoma compared to normal skin biopsies (Figure 11a).