Enhanced experimental metastasis of ultraviolet light-induced fibrosarcomas in ultraviolet light-irradiated syngeneic mice.

Some ultraviolet light (UV)-induced fibrosarcomas produce more experimental pulmonary tumor colonies in UV-irradiated hosts than in normal syngeneic recipients. The number of experimental metastases produced following i.v. injection of these tumors increases in proportion to the dose of UV radiation. This enhancement can be transferred with lymphoid cells to lethally X-irradiated recipients and with partially purified T-lymphocytes to untreated syngeneic mice. Some UV-induced fibrosarcomas do not form experimental metastases readily, even in UV-irradiated recipients, suggesting that both immunological and nonimmunological factors are important in limiting metastasis formation.