The MTT assay, reoported by Mosmann as a rapid and convenient colorimetric assay for cellular growth and survival, has been widely used as an in vitro chemosensitivity testing.
In fresh specimens obtained from patients undergoing gastrectomy, sensitivity to 5 fluorouracil(5-FU), cisplatin(CDDP), mitomycin(MMC) and adriamycin(ADM) was examined in 20 gastric adenocarcinomas using the MTT assay. The chemosensitivity was
considered as positive when the inhibition rate(1-mean absorbance in treated wells/mean absorbance in control wells x 100%) was equal to or more than 50%.
The inhibition rates of 5-FU, CDDP, MMC and ADM were 36.9±26.9%, 37.4±26.5%, and 49.3±25.3% respectively, with no significant differences. The efficacy rates of 5-FU, CDDP, MMC and ADM were 25%, 25%, 30%, and 50% respectively. Increase in
inhibition
rate was remarkable in the poorly differentiated adenocarcinomas, compared to the well differentiated adenocarcinomas, when exposed to 5-FU, CDDP, MMC and ADM. The response rate was higher in the poorly differentiated adenocarcinomas than in the
well
differentiated adenocarcinomas(50.0% versus 11.1%, P=0.0001). The overall response rate to the drugs was 32.5%.
These results suggest that there is a difference in chemosensitivity according to the anti cancer drugs and individual tumor tissues, and that chemosensitivity test using MTT assay can cerve as an effective tool for selection of appropriate
anticancer
drugs.
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