Cancer: Current concepts

Cancer is a genetically based disease that results in numerous gene alterations including the activation of oncogenes and the loss of tumor suppressors. When gene functions are disrupted, cells lose control of their growth either by the acceleration of cell proliferation or the inhibition of apoptosis. In addition, many features of cancers such as invasion and metastasis are also caused by the malfunction of those gene products. Recently, the mutator pathway has been implicated in cancer development. The disruption of the mutator pathway can cause cancers indirectly by mutating the oncogenes or tumor suppressors in an autosomal recessive fashion. Studies of the alterations of cancer-related genes have helped us to understand the molecular mechanisms of cancer development and to identify the tumor markers for diagnosis or as targets for cancer treatment. HER-2/neu is used as an example to demonstrate this concept.