Subsequently, we treated the B16F10 melanoma cells with a melanin synthesis activator (α-MSH, 200 nM), melanin synthesis inhibitor (arbutin, 100 μM), or OOM-SC-EVs (1.5, 3, 9, and 15 × 108 particles/mL) and found that OOM-SC-EV treatment led to an apparent inhibitory activity on α-MSH-induced melatonin synthesis in a dose-dependent manner (Figure 5C). Here, STAMBP is linked to melanoma.