Daunorubicin accumulation by human myeloblasts varying in anthracycline resistance.

Circulating myeloblasts were obtained from patients with acute myelogenous leukemias varying widely in anthracycline responsiveness. Studies were carried out in vitro to assess the capacity of such cells for daunorubicin accumulation. There was no correlation between drug responsiveness patterns in vivo vs. drug transport phenomena measured in vitro. A mode of enhanced anthracycline exodus demonstrable in certain drug-resistant murine leukemia cell lines could not be detected in the drug-resistant human myeloblasts.