Moisturizers, vehicle effects, and photocarcinogenesis.

Topically applied formulations (e.g., emollients and moisturizers) may influence the optical physics of skin and therefore the effectiveness of UVR exposures. In this issue, Lu et al. provide evidence for another type of influence by moisturizers, one that does not require the presence of the chemical agent before or during UVR exposure. Several such test agents applied after the completion of a course of UVR enhanced the tumor response in mice, both qualitatively and quantitatively. The study design is rational but the group sizes are modest, the resulting database is therefore limited, and the repeatability is not yet determined. Perhaps most important for the this Journal's readership, the clinical relevance is unknown and deserves detailed examination.