The effects of low temperatures (0° C., -30° C., -70° C., and -190° C.) on Sarcoma 37 of mice have been studied. In general, freezing does not appreciably alter the latent period of tumor transplants nor their morphological characteristics, either before transplantation or after the development of tumors. Exposure to 0°C. results in a percentage of “takes” which is inversely proportional to the duration of exposure, but exposure to lower temperatures results in as high a percentage of successful transplants as controls regardless of the duration of exposure used in these experiments.
Exposure to temperatures lower than 0° C. alters the tumor cells in some way as evidenced by (a) regression of some tumors after an initial period of growth and (b) a loss of viability of once-frozen tumor material after several subsequent passages in an unfrozen state. Repeated freezing and thawing also results in a loss of viability of tumor cells.
Serial short time-interval studies of frozen and unfrozen tumor transplants indicate a survival of transplanted cells in both groups.
These findings are discussed with respect to the concept of virus as the “continuing cause” of tumor formation.
This investigation was supported by a research grant from the Division of Research Grants and Fellowships of the National Institutes of Health, Public Health Service.