Abstract
A new and simplified method for screening of antitumor substances with in vitro-cultured tumor cells is presented. The effect of the test compound is determined by observation of the delayed appearance and long-lasting cytomorphological change of the cells through 72 hours of incubation. The method is especially suitable for sereening of antimitotic or radiomitotic substances, because the real characteristic damage on nuclei can be discriminated from an acute unspecific cytotoxicity. By this technique, it is possible to avoid the error of taking a depression of growth rate caused by a mere cytolysis or by direct destruction as an index of the true anti-tumor effectiveness.
