Clinical application of histoculture drug response assay (HDRA) - Distribution pattern of inhibition index and predictability of clinical chemo-therapy effects -

Histoculture drug response assay (HDRA) with MTT-endpoint was performed using the surgical specimens consisting of 79 gastric, 94 colorectal, 50 breast, 28 lung and 3 other cancers. The specimens were cut into pieces, placed onto collagen-gel-matrix in the medium containing mitomycin C, 5- fluorouracil, adriamycin, cisplatin for gastric, colorectal and breast cancers and were incubated for 7 days. Vindesine and etoposide were also applied for lung and other cancers. The viability of the tumor cells was measured with MTT-method of which inhibition index for positive at each cutoff concentration was 50% or more. Evaluable rates for gastric, colorectal, breast, lung and other were 90%, 93%, 98%, and 100%, respectively. Efficacy rate of each drug for breast and lung cancer at the same cutoff concentration with gastric and colorectal cancers, was close to the clinical one except mitomycin C in which 70% inhibition was estimated to be appropriate as cutoff for breast cancer. The clinical chemosensitivity pattern of each cancer was successfully reproduced in the distribution pattern of inhibition index detected by HDRA. Fifty percent true-positive rate and 95% true-negative rate were obtained by HDRA to predict the clinical chemotherapy effects, resulting in 82% accuracy.