The main goal of this study was to analyze, using proteomic techniques, changes in protein expression of acute myeloid leukemia (AML) cells that could give insights into a better early prognosis for tumor pathophysiology. Proteomic analysis of different subtypes of AML cells was carried out using 2-DE and MALDI-TOF PMF analysis. Proteins identified as more significantly altered between the different AMLs belonged to the group of suppressor genes, metabolic enzymes, antioxidants, structural proteins and signal transduction mediators. Among them, seven identified proteins were found significantly altered in almost all the AML blast cells analyzed in relation to normal mononuclear blood cells: alpha-enolase, RhoGDI2, annexin A10, catalase, peroxiredoxin 2, tromomyosin 3, and lipocortin 1 (annexin 1). These differentially expressed proteins are known to play important roles in cellular functions such as glycolysis, tumor suppression, apoptosis, angiogenesis and metastasis, and they might contribute to the adverse evolution of the disease. Proteomic analysis has identified for the first time novel proteins that may either help to form a differential prognosis or be used as markers for disease outcome, thus providing potential new targets for rational pathogenesis-based therapies of AML.