system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Animals, Mice, Mice, Hairless, Neoplasms, Radiation-Induced, Skin Neoplasms, Tattooing.
user
Do black tattoos protect against UVR-induced skin cancer in mice? Context: Black tattoos may involve risk of cancer owing to polycyclic aromatic hydrocarbons including benzo(a)pyrene (BaP) in inks. Ultraviolet radiation (UVR) induces skin cancer. The combination of UVR and black tattoo may therefore potentially be very problematic, but has not been previously studied. Immunocompetent C3.Cg/TifBomTac mice (n = 99) were tattooed on the back with Starbrite Tribal Black(™) . This ink has a high content of the carcinogen BaP. Half of the mice were irradiated with three standard erythema doses UVR thrice weekly. Time to induction of first, second and third squamous cell carcinoma (SCC) was measured. Controls were 'tattooed' without ink. All irradiated mice developed SCCs while no malignant tumours were found in the nonirradiated group. In the tattooed and irradiated group, the development of the first, second and third SCC was significantly delayed in comparison with the irradiated controls without black tattoos (212, 232, 247 days vs. 163, 183, 191 days, P < 0.001).
assistant
In UVR-irradiated black tattoos, remarkably, the development of UVR-induced skin cancer was delayed by the tattoos. Skin reflectance measurement indicated that the protective effect of black pigment in the dermis might be attributed to UVR absorption by black pigment below the epidermis and thereby reduction of backscattered radiation. Final Decision: yes