Chick embryo assay as chemosensitivity test for malignant glioma.

To predict the efficacy of anticancer drugs such as ACNU [1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl-3-nitrosoure a hydrochloride] and MCNU [1-(2-chloroethyl)-3-(methyl-alpha-D-glucopyranos-6-yl)-1-nitrosou rea] in the treatment of malignant gliomas, the usefulness of the chick embryo assay as a chemosensitivity test was studied. Fifty-seven surgical specimens including benign tumors were examined by this method. All tumor specimens tested could be grafted on the chorioallantoic membrane of chick embryo; the evaluable ratio was 100%. Twenty-one patients with previously untreated malignant glioma could be evaluated to test the predictability of the clinical effects, judged by computed tomography. There were 7 (78%) instances in which the assay response corresponded to a clinical partial response (true-positive). There were 2 (22%) false-positives for the assay, 0 (0%) false-negative and 12 (100%) true-negatives. The over-all predictive accuracy was 90% (19/21). Thus, a high-degree of positive association exists between the chick embryo assay and the clinical outcome. This in vivo assay system for malignant glioma is advantageous for chemosensitivity tests because of its convenience, rapidity, and inexpensiveness.