A 30-year-old man has had a progressively worsening productive cough for one month. On physical examination, a few small nontender lymph nodes are palpable in the axillae, and the tip of the spleen is palpable. Laboratory studies show Hgb 10.2 g/dL, Hct 31.1%, MCV 90 fL, WBC count 67,000/microliter, and platelet count 36,000/ microliter. Microscopic examination of his peripheral blood smear shows many blasts with Auer rods. Which of the following is the most likely diagnosis?