[A new concept: treatment using differentiation of the malignant cell in man]

Against the dogma of the irreversibility of malignant cells, although genetical abnormalities, human leukemic cells have been differenciated. According to Leo Sachs proposals on the proliferation-differentiation balance impairment in malignancies we have shown various orientation for the differentiation therapy: inhibition of malignant cells using low dose of Cytosine Arabinoside in acute myeloid leukemia; suppression of the growth factor effect such as the role of interferon in hairy cell leukemia; targetted differentiation process by all trans retinoic acid in acute promyelocytic leukemia with the obtention of complete remission in all cases; differentiation of malignant and normal cells by G-CSF in acute myeloid leukemia in elderly patients. Differentiation therapy induces a modulation in the cell program. Cells mature, becoming differentiated, die, disappear and are replaced by normal cells. The addition of differentiation treatment to chemotherapy greatly improves the chance of long term survival.