Quantitative Studies on the Effect of X-Rays on Neoplastic Cells. ∗

Abstract

Summary

The experiments described indicate conspicuous differences in susceptibility to X-rays among different neoplastic cells of mice. They support the opinion that X-rays so injure cells that multiplication can proceed only for a few cell generations, after which they degenerate and die. Viruses producing neoplasms are far more resistant to X-rays and it seems probable that exposure in vitro to approximately 15, 000 r units of X-rays distinguishes between virus-containing and virus-free neoplasms, the latter losing the ability to transmit the disease when exposed to 15,000 r units of X-rays in vitro. Viruses are unaffected by the amount of irradiation used in these studies. Irradiated sarcoma cells multiply for several days and then die. Hence, failure to produce the disease with irradiated neoplastic cells is the best evidence available thus far that the neoplasms of mice studied are not transmitted by viruses.