IL15RA and melanoma: Flow cytometric analysis (Figure 3A) shows that, in both primary/metastatic pairs of melanoma cultures, PMA treatment (100 ng/mL for 3 h) causes a statistically significant decreased surface expression of mbIL-15/IL-15Rα (p < 0.05) in the metastatic samples (WM-266–4, G1, A2058, and SK-MEL28) but not in the primary ones (WM-115 and T1).