[The changes of mRNAs of both c-myc and MDR1 in CML-bc tumor cells during the clinical course: a case report].

We examined the expressions of both c-myc and MDR1 in four samples isolated from a CML-bc patient in series during the clinical course. A 46-year-old man was diagnosed as chronic phase of CML in june 1985. In February 1987, the diagnosis of blastic transformation was made because of marked increase of blastic cells. He was initially treated with vincristine (V) and prednisolone (P) successfully. However, the effect of VP therapy was gradually attenuated, so that combined chemotherapies including anthracyclines were started. After the treatments of several courses, tumor cells acquired the refractory to both vincristine and adriamycin . He died in January, 1988. Northern blot hybridization studies revealed no expression of MDR1 mRNAs. However, the expression of c-myc was increased in the latest sample. These findings suggest that the expression of c-myc mRNA in tumor cells of this case reflects one characteristic of clinically refractory states to chemotherapies.