Cell marker analysis in acute monocytic leukemias.

Leukemic cells from nine cases of acute monocytic leukemia (AMoL) were characterized by multiple differentiation markers. Cells in most cases were phagocytic, carried an Fc receptor, and stained positively for alpha-naphthyl acetate esterase but negatively for naphthol AS-D chloroacetate esterase. However, subtle differences in marker expression were observed which suggested different degrees of leukemic cellular maturation or activation. Cell marker analysis proved to be a useful adjunct to conventional morphology in confirming the diagnosis and the recognition of the neoplastic cells in AMoL, and may ultimately provide insight into the functional state of these cells.