Cancer development is considered by the dysregulated proliferation of transformed cells. In recent years, dramatic and remarkable insight into the molecular mechanisms of this phenomenon have come from basic cancer research. Detailed knowledge of the molecular mechanisms and pathophysiology of cancer allows therapeutic agents to be designed that specifically target aberrant cellular processes. There are currently a number of targeted treatment strategies with less toxicity being evaluated. In the future, it is likely that this mechanistic and targeted approach will have a significant impact on clinical oncology and the diagnostic evaluation of tumors.