Genes and Cancer

If we look at life as a book, Genes are the basic alphabet of this book. They determine the make of the contents, the messages and meanings of our lives. Genes are very small molecules in our cells, which determine almost everything in our body. All of us, one day, were just one cell, a fertilized ovum. One sperm cell from our father joined with one ovum from our mother, merging their genes and forming one cell. From there on, the cells divided and gradually formed various tissues and organs of our body.

Each Sperm and Ovum carry one copy of our parents' genetic map. The genes were then merged and passed on to us. And now, each cell of your body contains genetic information from both our parents.

The circles indicate the cells and the red and green columns indicate the complex of our genes within the cells. Each and every cell of our body contains same complex set of genes, 1/2 from our mother and 1/2 from our father.

Our parents inherited their genes from their parents, and the grand-parents from their great-grant parents and so on. This means that each part of our genes may belong to a grand parent, great grand parent or our parents,--and if some one had a bad gene a few generations ago, we may harbor it, -- generations later.

Our genes are clumped together in 23 pairs of chromosomes. Each chromosome contains genes from both parents. Simply, if you imagine the red and green columns in above picture as one chromosome, we have 23 pairs of Red and Green in each cell of our body.

With advancements in technology, we can now detect certain bad genes inside the cells. These bad genes that are known to be associated with causation of certain cancers. 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. Some of these 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:

Tumor Suppressor Genes: Our cells have variety of genes, some of which control their growth These genes are important part of our genetic makeup and they regulate growth and multiplication of the cells. As a result they can prevent cancers from happening. If something goes wrong with these genes, and if they don't function properly, cells may grow without a control and cause cancer.

p53 gene; p53 suppresser gene can arrest replication of cells with damaged genes until normal repair process has taken place. If cells with damaged genes grow and replicate, they may result in a cancer. p53 gene suppresses the growth of such cells. If this genes goes bad, it can lead to the development of Breast, Colon, Leukemia, soft tissue sarcomas, and many other cancers.

APC gene; if this genes goes bad, it can lead to the development of Colon, Pancreas and Stomach cancers.

BRCA1; located in chromosome 17, if this genes goes bad, it can be associated with a very high risk of developing Breast cancer.

BRCA2; located in chromosome 13, if this genes goes bad, it can be associated with a very high risk of developing Breast cancer.

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. These genes stimulate cell growth. On occasions, these genes can be overactive and cause rapid cell growth and cause a cancer. Example of these genes are:

Why to test?	Genes and Cancer	Available Tests
Breast Cancer	Ovarian Cancer	Colon and Rectal Cancer
Rare Cancers	Cancer Syndromes	Who needs to be tested?
Prostate Cancer	Discrimination	Costs
Family Issues		Other Issues