Heterogeneity of human adenocarcinomas of the colon and the stomach as regards sensitivity to cytostatic drugs.

In the present paper a test model was used to examine if human adenocarcinomas of the colon and the stomach are heterogenous as regards the sensitivity to cytosine arabinoside, melphalan, vinblastine sulphate, amethopterin and 5-fluorouracil in vitro. The effects of the five drugs were measured as the differences in incorporation of tritiated thymidine and deoxyuridine in drug-containing tubes and control tubes. It was found, that different parts of eleven colon and five stomach cancers differ significantly in their sensitivity to the same cytostatic treatment in vitro.