Melanoma cells may have enhanced endocytosis and degradative pathways from early endosome to lysosome interactions, as evidenced by the upregulation in some specific cell surface receptors (e.g., IGF1R and Syntenin-1), RAB5-associated early endosomes, RAB7-associated late endosomes, lysosome proteases CTSB, and the trafficking molecule TBC1D16 [12,55,74,75,76]. Here, CTSB is linked to melanoma.