The shady side of sunlight: Current understanding of the mechanisms underlying UV-induction of skin cancers

The incidence of skin cancer has been rising at an astonishing rate, particularly that of the deadliest skin cancer, melanoma. While the molecular mechanisms of sunlight ultraviolet radiation (UV)-induced non-melanoma skin cancer (NMSC) have been well documented, there is a major gap in our current knowledge of how UV initiates melanoma. However, the components of the retinoblastoma (Rb) pathway, the p53 and the p16 pathways are considered the major targets of UV-induced NMSC and melanoma, respectively. Our recent study has revealed that these two pathways coordinate the early responses to UV radiation in the skin. Here, we review the value of studies targeting these early events of skin carcinogenesis, with specific focus on the critical role of the components of the Rb pathway.