Cancer can be treated by new form of therapy known as targeted therapy. Targeted therapy uses drugs or other chemical substances, which have the ability to identify cancer cells. This therapy targets the cellular or molecular difference of the cancer cell from normal cell. Targeted therapy changes the way cancer cell interacts with other cell, cancer cell growth and division.
Targeted therapy can be used to treat some types of cancer like lung, head and neck, liver, breast, kidney and colorectal cancer.
How does it work?
Normal cells go through a process known as carcinogenesis to become a cancerous cell. Many types of molecules and signals are required for the process of carcinogenesis. Targeted therapy blocks this process of carcinogenesis by changing the cellular and molecular signals.
Enzymes play a major role in controlling everything in our body, like the gene expression, signal transduction and much more. Targeted therapy uses enzyme inhibitors to stop or disrupt the signals which are required to change a normal cell into a cancer cell. Therefore this type of targeted therapy stops the spreading of tumor or cancer and help in improving the life span of the cancer patients. The drugs used in this type of targeted therapy are known as signal transduction inhibitor or enzyme-inhibitor.
Apoptosis Inducing Drugs:
Some type of targeted therapy change the structure of proteins which are present in the cancer cell. This change in the protein leads to cell death or apoptosis. Since these drugs induce apoptosis or cell death so the name apoptosis inducing drugs. These drugs only target the cancer cell and will not induce any affect on healthy cells.
Cancer cells divide rapidly and form new cells. These cells require energy and oxygen for their survival and further cell division. These cancer cells are fed by newly formed blood vessels. The new blood vessel formation process is known as angiogenesis. Angiogenesis inhibitors which are used in targeted therapy blocks the formation of new blood vessel formation hence stops the cancer cell division and growth.
The angiogenesis inhibitor drugs block the vascular endothelial growth factor, which are required for the formation of new blood vessels around the tumor. This blocks the angiogenesis and hence the tumor cells become deprived of food and energy finally leading to the death.
Drugs used in Targeted Therapy:
1. Gleevec is the first targeted therapy drug used to treat gastrointestinal stromal tumor and some types of leukaemia. Gleevec targets the formation and function of abnormal proteins that promote the abnormal tumor cell growth.
2. Iressa is used as targeted drug therapy to treat patients with non-small cell lung cancer. Iressa targets epidermal growth factor receptor hence blocks the signals required for cancer cell growth and cell division.
3. Sutent is a enzyme inhibitor used to treat patient with advanced kidney cancer and gastrointestinal stromal tumor. The drug blocks the enzyme tyrosine kinase, hence inhibits the formation of new blood vessels around tumor thus stops tumor cell growth and spread.
4. Monoclonal antibodies, cancer vaccines, cytokines are also used to treat cancer by targeted therapy.
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