DIFFERENTIATION OF HUMAN LEUKEMIAS IN RESPONSE TO 12-0-TETRADECANOYLPHORBOL-13-ACETATE INVITRO

Abstract

Leukemic cells from patients with acute myeloid leukemia underwent morphological, functional and histochemical changes within 24-48 h after treatment with 1.6 .times. 10-18 M 12-O-tetradecanoylphorbol-13-acetate (TPA). The changes included adhesion to the plastic substrate, a 4- to 6-fold increase in the number of phagocytic cells and an increase in the number of .alpha.-naphthyl-acetate esterase (.alpha.-NAE) positive cells. TPA treatment of cells from patients with acute lymphoblastic leukemia caused some aggregation of cells in suspension, but no changes in adhesion, phagocytosis or .alpha.-NAE. Of the 4 cases of undifferentiated or unclassified leukemias studied, two failed to respond to TPA, one responded with a myeloid (adhesion) pattern, and one with a lymphoid (aggregation) pattern. Leukemic myeloblasts apparently retain the ability to express a variety of differentiated functions. It may be possible to use TPA as a tool to test the differentiative potential of undifferentiated human leukemias.