Leukemic cell maturation.

Leukemic blasts can be induced by external chemical agents to mature to neutrophils, monocytes, or RBCs. The phenotype of leukemic cells thus results from both internal genetic aberrations and the response of leukemic cells to their external environment. When human myeloid leukemia cells are exposed in vitro to a variety of agents (eg, vitamin A or dimethyl sulfoxide) the blasts lose their proliferative potential, the expression of oncogene products is sharply decreased, and after five days the leukemic cells become morphologically mature and functional neutrophils. Some patients with myeloid leukemias have responded to therapy designed to induce maturation in vivo. The induced maturation of leukemic cells is a new therapeutic tactic--an alternative to cytotoxic drug therapy--wherein leukemic cells are destroyed by transforming them into neutrophils.