Targeted Cancer Therapy

Advances in the knowledge of molecular biology of cancer and pathways involved in malignant transformation of cells are revolutionizing the approach to cancer treatment with a focus on targeted cancer therapy. Targeted cancer therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecules involved in cancer growth and progression. Because scientists often call these molecules “molecular targets,” targeted cancer therapies are sometimes called “molecularly targeted drugs. Advances in molecular biology, cellular biology and genomics have substantially increased the detailed understanding of the molecular pathology of cancer in terms of genetic mutation, altered gene expression and the
Most targeted therapies are either small-molecule drugs or monoclonal antibodies. Small-molecule drugs are able to diffuse across cell membrane and into the cells are small-molecule drugs, also called signal-transduction inhibitors. These drugs are able target the receptors located outside the cell, but they are also able to target abnormal proteins, or enzymes, that form inside cancer cells. Monoclonal antibodies are large proteins that cannot easily cross cell’s plasma membranes, so they are used to target molecules that are outside the cell or receptors on the cell
Angiogenesis is the process of forming new blood vessels.Normally, angiogenesis is thought of as a healthy process, as new blood vessels can help the body heal and repair damaged tissues. But in a person with cancer angiogenesis has important role in facilitating the survival, growth and spread of cancer. New blood vessels feed the cancer cells oxygen and nutrients allowing these cells to grow, invade nearby tissue spread to other parts of the body, and form new colonies of cancer cells. Scientists have found that the newly developing capillary cells release substances that help the cancer cells to detach from the primary tumor and get into the bloodstream. In order to continue to grow and survive cancer cells must find a way to make new blood vessels. So to stimulate new blood vessel growth they release high levels of specific proteins, called growth factors to the surrounding area. One of the main proteins in forming new blood vessels is vascular endothelial growth factor (VEGF). VEGF and other pro-angiogeneic proteins specifically attach to and activate the receptors on the surface of endothelial cells of the nearby existing blood vessels. In response to the signal,the endothelial cells start growing new blood vessels. Antiangiogenesis drugs bind to VEGF and this prevents VEGF from