Ultraviolet radiation-induced murine tumors produced in the absence of ultraviolet radiation-induced systemic tumor immunosuppression.
Using micro-UV-irradiation versus whole-dorsal irradiation for inducing cutaneous carcinomas in Skh:HRI mice and an assay for UV radiation (UVR)-induced systemic tumor immunosuppression, the dependence upon systemic immunosuppression for the growth of UVR-induced carcinomas was examined. Squamous cell carcinomas were produced by repeated microirradiation of 0.8-cm2 middorsal skin with xenon are solar-simulated UVR. These tumors were excised from tumor-bearing animals who 7 days later were inoculated ventrally with a cloned UVR-induced squamous cell carcinoma cell line, the T51/6. This cell line only grows in UVR-induced immunosuppressed Skh:HRI mice. In two separate experiments T51/6 inocula failed to grow significantly in the previously tumor-bearing animals (1 of 13) and in unirradiated mice (0 of 19), whereas it grew in 100% (15 of 15) of animals given a whole-dorsal subcarcinogenic UVR dose from a filtered fluorescent tube solar simulator. No sinecomitant immune response to the T51/6 was found in previously UVR-induced tumor-bearing animals. In contrast to whole-dorsal UVR-induced tumors, microirradiation-induced squamous cell carcinomas, whose original growth environment lacked UVR-induced systemic tumor immunosuppression, did not grow preferentially in mice given an immunosuppressive dose of UVR. However both the whole-dorsal and microirradiation-induced tumors were shown to be poorly antigenic, since they lacked preferential growth in athymic nude mice. These observations provide evidence that UVR-induced systemic tumor immunosuppression is not necessary for the production of UVR-induced tumors. However, it does cause a positive selection pressure during tumor formation, independent of the carcinogenic effect of UVR, which affects the transplantation biology of a tumor.
Menzies
S W
SW
Department of Veterinary Pathology, University of Sydney, New South Wales, Australia.
Greenoak
G E
GE
Reeve
V E
VE
Gallagher
C H
CH
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000276:immunology*; D005260:Female; D006084:Graft Rejection; D007108:Immune Tolerance / Q000528:radiation effects*; D051379:Mice; D008812:Mice, Hairless; D009368:Neoplasm Transplantation; D009381:Neoplasms, Radiation-Induced / Q000276:immunology*; D011829:Radiation Dosage; D012878:Skin Neoplasms / Q000276:immunology*