[Theory and actual attempts to establish an effective cancer chemotherapy]

In order to establish an effective cancer chemotherapy, theoretical analyses of chemoresistance factors in recurrent patients and possible approaches to curative chemotherapy were undertaken. Multidrug resistance of tumor cells in recurrent patients may hamper the development of new antitumor agents. Thus, we developed a new screening method (FACS method) which employs fresh clinical specimens. By this method, TAS-103 was found to be far more effective than 10 standard drugs and to be one of the most effective drugs among 20 or more new antitumor agents under study. Development of several effective drugs, such as TAS-103, might lead to a curative cancer chemotherapy.