Although the exact biological effect of the Rb activity in melanoma A375 and RPMI7951 cells exposed to FICZ and RPMI8951 cells exposed to KYNA is unknown, it should be noted that Rb interacts not only with cyclins, CDKs, phosphatases and chromatin-associated proteins but is also involved in regulation of metabolic pathways [46,47,48]. Here, RB1 is linked to melanoma.