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 resultant deregulation of biochemical signaling pathways and have given researchers the knowledge of the molecular pathways that give cancer their inherited pathogenic properties like their cunning ability to survive, avoid destruction, and grow uncontrollably.
These advances are being translated into the new and exciting area of targeted cancer therapy] that aim at the particular molecular targets that are responsible for driving the various key stages of cancer causation and malignant progression are revolutionizing options for cancer treatment This revolution can be seen in the transition from the traditional therapies of blanketed destruction, like cytotoxic agents and radiation therapy, of the past toward targeted treatments that are designed specifically to overcome the precise molecular abnormalities that are responsible for the induction and progression of cancer.
With this new innovative approach that uses cancer treatments designed to inhibit only cancerous cells replication and growth, therapy can now be delivered with maximum therapeutic benefits, while minimizing toxicity and sparing healthy tissues and healthy cells alike, targeted therapies are and are generally well tolerated by patients harm. While traditional therapies can be effective, they lack of sensitivity and specificity which leads to severe side effects and limited efficiency.
Even though they aim to destroy rapidly dividing cancer cells, they inadvertently also destroy the rapidly dividing cells of the healthy tissues. Cytotoxic drugs, such as chemotherapy, in addition to the collateral damage it causes because it does not distinguish between cancer and healthy cells, it is now known be problematic because the emergence of drug resistant cancers. Radiation therapy kills healthy cells that are in the path of the radiation or near the cancer being treated. Treatment-related damage to healthy cells leads to complications of treatment, or side effects.
These side effects may be severe, reducing a patient’s quality of life, compromising their ability to receive their full treatment all which can limit their chance for an optimal outcome from treatment. Fortunately targeted cancer therapies use drugs or substances to interfere with specific molecules involved in carcinogenesis and growth. Since they focus on molecular and cellular changes that are specific to cancer, targeted cancer therapies can be more effective than current treatments and less harmful to normal cells.
Targeted therapies interfere with cancer’s vital mechanisms of survival through processes that control growth, survival,division, and spread of cancer cells, as well as the signals that cause apoptosis and angiogenesis. Although there are many types of targeted treatments and while some work with different mechanisms, the thing all targeted therapies have in common is their ability to specifically target cancer cells and ultimately affect their growth and survival. 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 surface.
A crucial type of molecular targeted therapies are designed to inhibit cancer cells from making new networks of blood vessel are called angiogenesis inhibitors or antiangiogenesis drugs. 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 interacting with its receptor,VEGFR) on the surface on endothelial cells, a step that is necessary for the initiation of new blood vessel growth binds to VEGF and keeps it away from receptors on the surface of endothelial cells.
Cells no longer receive a signal for increased blood flow, so new blood vessels are not formed. This starves the cancer cells of the blood, nutrients, oxygen that are needed for its survival and continued to growth. Since a blood supply is essential for cancer to survive , grow beyond a certain size, have the ability to metastasize, blocking angiogenesis is an ideal strategy for cancer therapy. Many antiangiogenesis agents already have FDA approval and many more are being researched or in clinical trials.
A dramatic increase in understanding how cancer cells sabotage normal cellular signaling systems to drive malignant progression In addition to all the physical benefits of targeted cancer treatment I believe that it will have psychological benefits as well. Many people will say that the treatments of cancer are worse than the disease itself. Obviously people are scared when they are diagnosed with cancer, but many people are just as or even more scared of the treatments.
The issue is that with the uncertainity of survival people do not want to spend the remaining time being tortured with treatments that have such significant side effects that some people rather die sooner than being subjected to. Advances in the knowledge of molecular biology of cancer and pathways involved in malignant transformation of cells are revolutionizing the approaches to cancer treatment with a focus is on targeted cancer therapy and personalized targeted medicine (A)National cancer institute,Tageted Cancer Therapy.http://www. cancer. gov.