A 33-year-old male presents with fever for 1 week, accompanied by epistaxis, gingival bleeding, subconjunctival hemorrhage, and large ecchymoses at injection sites. Stool is purplish-red. Laboratory tests: Hb 85g/L, WBC 1.5×10<sup>9</sup>/L, PLT 53×10<sup>9</sup>/L. Bone marrow examination shows markedly hypercellular nucleated cells with blast cells accounting for 85%. POX strongly positive. Chromosomal analysis reveals t(15;17). The most likely cause of bleeding in this case is: