HRH4 and melanoma: Interestingly, H4R expression levels inversely correlated with MI evaluated in melanoma biopsies (Figure 5C, Spearman rho correlation coefficient r: −0.5770, **P = 0.0097) and with PCNA expression (Figure 5B, 5D, Spearman rho correlation coefficient r: −0.7240, ***P = 0.0005), reinforcing the idea of an important relationship between the expression levels of this receptor subtype and the rate of proliferation exclusively in melanomas (Figure 5E–5L).