CANCER CAUSED

Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemical or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication or are inherited, and thus present in all cells from birth. The heritability of cancers are usually affected by complex interactions between carcinogens and the host's gnome. New aspects of the genetics of cancer pathogenesis, such as DNA methylation ,and microRNAs are increasingly recognized as important.

“Risky behavior This just means indulging in something that increases your risk. It may be smoking, or drinking too much, or eating a very unhealthy diet. Some of us look after ourselves better than others. And this can have a real effect on our health. But some people look after themselves really well and still get cancer. While others don't seem to look after themselves at all and never do. “

Genetic abnormalities found in cancer typically affect two general classes of genes.

· Cancer-promoting oncogenes are typically activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments.

· Tumor suppressor genes are then inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle , orientation and adhesion within tissues, and interaction with protective cells of the immune system.