Time of appearance and histology of tumors induced in the dorsal skin of C3Hf mice by ultraviolet radiation from a mercury arc lamp.
The time course of skin tumor induction was determined in hair-clipped inbred agouti C3Hf mice irradiated three times per week with a medium-pressure quartz-mercury lamp; 4 different UV doses were used. Although the ears were also exposed to the radiation, in the 3 groups given the highest doses no ear tumors were observed by the time each animal had developed at least 1 tumor on its back. No tumors were found in the animals receiving the lowest UV dose. In the group receiving the highest dose, males developed tumors earlier than did females; this trend continued in the lower dose groups. Many tumors that developed in the back skin were well-differentiated squamous cell carcinomas. Others were less well-differentiated squamous cell carcinomas. Others were less well defined so that the cell of origin was difficult to determine. In the group receiving the highest UV dose, the squamous cell carcinomas were few, whereas at the lower doses they predominated.
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000209:etiology* / Q000473:pathology; D004307:Dose-Response Relationship, Radiation; D005260:Female; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000209:etiology; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000473:pathology; D012878:Skin Neoplasms / Q000209:etiology* / Q000473:pathology; D013997:Time Factors; D014466:Ultraviolet Rays