Targeted agents are typically small molecules or monoclonal antibodies used in targeted cancer therapies. Agents are selected based on their ability to interfere with the proteins, or molecular targets, which have been identified as promoting growth and survival in a tumor cell. Targeted agents are developed to interact with molecular targets found on the surface of a cell or inside the cell. Small molecules are better candidates for targets within the cell because they can easily move through the cell wall. Approved targeted cancer therapies include:
- Hormone therapies—interfere with tumor growth
- Signal transduction inhibitors—interfere with a cell’s ability to respond to signals
- Gene expression modulators—alter the proteins responsible for expressing a certain gene
- Apoptosis inducers—responsible for controlled cell death of cancer cells
- Angiogenesis inhibitors—stop the growth of a new blood supply to cancer cells
- Immunotherapies—signal the immune system to kill cancer cells
Limitations for targeted cancer therapies is that the cancer cells can become resistant to the agent.