Gene Therapy

Genes play a significant role in development of cancers. Genes are the core molecules within the cells that carry vital information about the cells and ultimately lead into production of different chemical substances that are needed for the life and their well being. There are many forms of gene related illnesses, all together referred to as genetic disorders. These illnesses may or may not be associated with a cancer. Hemophilia is due to lack of genes that govern production of s specific clotting factor. Dawn syndrome or Mongolism is also a genetic disorder. Gene replacement therapy has been successful in a handful of conditions, whereby an abnormal gene is substituted with a normal one. The process of substituting abnormal genes is a very difficult and complicated one. This method of treatment is not widely available either.

Genes have many different functions. As far as their role in cancer goes, there are genes that control the development and growth of cells. Certain genes promote and certain genes inhibit cell growth. There has been a great degree of hype about genetic cancer treatment. This technology is still at its infancy and has not been even properly tested to see whether it works. We still need to expand our knowledge about the genetic controls and the function of the genes within cancer cells.

Gene therapy for cancers, as it stands today, is extremely experimental and we have no idea where it may take us. It may be the way to future or it may be disbanded like many other experimental treatments used in the past. Having said that, lets review some of the facts about it.

Genes and cancer

Unlike the genetic abnormalities of benign disorders, the genetic problems associated with cancers are for most part not understood and seem to be very complex and multiple in nature. Such abnormalities develop during the life of a cancer patient, as opposed to the hereditary nature of the benign genetic illnesses. Our current understanding about genes and their role in cancer divides them into two important categories of genes which are involved in the process of cancer development and progression:

Oncogenes: These are among essential components of normal genes within the cells and if for some reason activated, they can eventually cause a cancer. These genes regulate normal growth of cells. More than 100 Oncogenes have been identified and associated with some form of cancer. What is unknown is "what activates these Oncogenes and what happens after they are activated?" External factors, radiation, certain chemicals may cause activation of Oncogenes and result in a cancer.

Tumor Suppresser Genes: These genes are important part of our genetic makeup and they regulate cell growth and multiplication. For Example p53 suppresser gene can arrest replication of cells with damaged genes until normal repair process has taken place. If cells with damaged genes grows and replicate, they may result in a cancer. p53 gene suppresses the growth of such cells.

Successful gene therapy depends of efficient transfer of healthy genes into the target cells. This is the most difficult step of the way in cancer treatment. The current methods use a virus that carries the normal gene(s) into the cancer cells. Most these viruses are semi-synthesized in laboratory. Up to this date there is no single accepted method of doing the gene transfer. Many experimental protocols have been designed to try to discover the best methods, yet we are still nowhere near where we should be.

Drug resistance gene therapy for bone marrow protection:

Bone marrow cells are sensitive to chemotherapy drugs and this imposes a limit as to how much chemotherapy can be used.  Certain cancers have or develop a genetic mechanism (MDR1 gene), by way of which they become resistant to the cancer drugs.  If one would transfer this genetic mechanism from the cancer cells into the bone marrow cells, then a much higher doses of chemotherapy can be used with much less complications that may be due to marrow suppression.   Clinical trials have shown that women with breast cancer who were treated with MDR1 gene therapy, have been able to tolerate higher odes of chemotherapy with Taxol.

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