[In vitro evaluation of the chemosensitivity of malignant gastrointestinal tumors by stem cell assay].

The Human Tumor Stem Cell Assay, originally described by Hamburger and Salmon, was shown to be a useful in-vitro technique for predicting response or lack of response in individual patients' tumors. In the present study 34 GI-tumors were assayed for evaluation of in-vitro growth characteristics and sensitivity-patterns to standard chemotherapeutic drugs as well as to recombinant interferon alpha-2(rIF). Sufficient growth for evaluation of anticancer drug activity (greater than 30 colonies/control plate) was obtained in 56% of specimens: 2/9 colorectal, 0/3 stomach, 0/3 pancreatic tumors and 1/4 hepatomas revealed a 50% (or more) decrease of TCFUs, that was considered the minimum for in-vitro efficacy. Our results suggest a very limited overall activity of rIF in gastrointestinal malignancies. Only 1 pancreatic cancer (of 18 evaluable specimens) showed a significant decrease of colony formation (70%), when 100 U of interferon/ml were added to the culture system.