Differentiation of Human Leukemias in Response to 12 - O - Tetradecanoylphorbol - 13 - Acetate In Vitro

Leukemic cells from patients with acute myeloid leukemia underwent morphological. functional. and histochemical changes within 24-48 hr after treatment with 1 .6 x iO’ M 12-0-tetradecanoylphorbol-13-acetate (TPA). The changes included adhesion to the plastic substrate. a 4-6-fold increase in the number of phagocytic cells, and an increase in the number of alpha-naphthyl-acetate esterase (a-NAE) positive cells. In contrast. TPA treatment of cells from patients with acute lymphoblastic leukemia caused some aggregation of cells in suspension. but no changes in adhesion. phagocytosis. or a-NAE. Of the four 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. These data suggest that leukemic myeloblasts retain the ability to express a variety of differentiated functions. and in some cases. it may be possible to use TPA as a tool to test the differentiative potential of undifferentiated human leukemias.