The rapidly expanding knowledge of the pathogenesis of cancer at the molecular level is providing new targets for drug discovery and development. However, cancer is a complex disease characterized by multiple genetic and molecular alterations affecting cell proliferation, survival, differentiation and invasion among others. Many of these alterations represent potential targets for the development of new anticancer therapeutics. Because of the enormous biological diversity of cancer, it is unlikely that attacking only one of these targets will eliminate a malignant cell. Rather, strategic combination of agents targeted against the most critical of those alterations will be needed. Another approach that is rendering promising clinical results is the use of more unspecific agents that inhibit or modulate several relevant targets simultaneously. A deep biologic understanding of the relative relevance of each target in different cancer types will be key to efficiently direct those drugs to diseases more likely to benefit from its particular modulation profile.