Clinical application of the clonogenic assay.

Simple methods were developed for cloning human solid tumors; 68 percent of the tumors processed formed at least 30 colonies within two to four weeks. The accuracy of the clonogenic assay for predicting clinical response was determined in a prospective, correlative study. Eight-four patients had objectively measurable disease and had at least one course of chemotherapy. Tumor types included melanoma (33), lung (12), colon (7), breast (7), stomach (4), ovarian (12), sarcoma (7), and hepatoma (2). For patients whose tumors were sensitive in vitro to a particular drug, clinical response was seen in 21/25 cases (84 percent). Tumor resistance was found in 59 instances, and 54 patients (92 percent) had no clinical response to the same drugs. Associations between in vitro chemosensitivities and clinical course were highly significant.