TYR and melanoma: Co-treatment of α-MSH–stimulated B16F10 melanoma cells with BK-5 exosomes (8.45 × 106, 1.69 × 107, and 3.38 × 107 particles/ml) resulted in a concentration-dependent decrease in tyrosinase activity, with a statistically significant reduction observed at the highest concentration (3.38 × 107 particles/ml)(Fig. 8).