 NMSCs are a particular problem for organ transplant recipients OTRs, who must take medicines to protect against rejection of their transplanted organ. These drugs suppress the host immune response that serves to identify and eliminate mutant and neoplastic keratinocytes before they can progress to clinically apparent cancers. Recent research indicates that these drugs also augment signal transduction pathways involved in skin tumor development. NMSCs develop much more frequently in long-term recipients of renal allografts and once present, they behave more aggressively. In immunosuppressed patients, the risk of developing SCCs is 65250-fold higher than in the general population, and the risk of BCCs is 10-fold greater. The rate of SCC metastases in organ transplant recipients is 7, which is much higher than the general population. For this reason, there has been great interest in identifying novel agents for chemoprevention, which are suitable for use by OTRs. 