CD4 and melanoma: Significantly increased frequencies of CD25+ cells that include both FoxP3+ and FoxP3- populations, were observed for CD4+ (p = 0.01) and CD4-CD8- (p = 0.0038) T cell subsets in blood from canine melanoma patients (n = 16) compared to healthy controls (n = 20) (Figures 4A,B).