Immunophenotyping by flow cytometry of BM aspirate revealed a blast cell population including 15% myeloblasts (CD34+, HLADR+, CD13+, CD33+, and CD38+) and 25% promonocytes (CD64+, CD13+, CD33+, HLADR+, and aberrant expression of CD56), a profile compatible with acute myelomonocytic leukemia. The gene discussed is CD33; the disease is acute myelomonocytic leukemia M4.