Targeted therapy: novel agents against cancer.

Nowadays, malignancies still are crucial problems of healthcare system in many aspects including efficacy of therapeutic modalities, quality of patients' life and cost of treatment. The understanding of genetic alterations and intracellular pathways are very helpful to define the pathologic abnormalities specific to each cancer Consequently, there have been recently discovered agents which destroy the cancer cells with higher specificity than previously used agents. "Targeted therapy" is established to call this group of drugs because its mechanism of action selectively targets on tumor-specific abnormal cellular processes. These aimed extracellular or intracellular mechanisms are mainly divided into 3 groups; (1) activating natural immune system directly against tumor cells, (2) inhibiting cellular proliferation, (3) inducing tumor anti-angiogenesis. The targeted drugs are currently studied to establish the appropriate regimens for cancers with or without concurrent chemotherapy. It is important to understand and keep updated in these novel agents for better clinical outcome of cancer patients.