[In vitro phase II-III study by clonogenic assay: the combined effects of mitomycin C with alpha-interferon]

Using the human tumor clonogenic assay technique, the combined effects of mitomycin C (MMC) with alpha-interferon (HLBI) were surveyed in comparison with 33 fresh human tumor specimens. Tumors in this study were 16 gastric cancers, five breast cancers, four liposarcomas, three colon cancers, two gall bladder cancers, two esophageal cancers, and one hepatoma. When the survival fraction observed in drug combination was smaller than the multiplication of each survival fraction observed in each drug alone, the combined effects were considered to be synergistic. Twenty-two of 33 tumors (gastric cancer 11/16, breast cancer 5/5, liposarcoma 2/4, colon cancer 1/3, gall bladder cancer 2/2, esophageal cancer 1/2, and hepatoma 0/1) formed adequate colony numbers for the evaluation of combined drug effects. Synergistic effects were observed in seven tumors (three gastric cancers, one breast cancer, one gall bladder cancer, one liposarcoma and one esophageal cancer), although three tumors (one gastric cancer, one gall bladder cancer, and one colon cancer) exhibited antagonistic effects.