What Is Cancer ?

cancer is a growth disorder of cell. It is starts when an apparently normal cell begins to grow in an uncontrolled and invasive way.The result is a cluster of cells, called tumor, that constantly expands in size. Cells that leave tumors and spread throughout the body, forming new tumors at distant sites,are called metastases.Cancer is perhaps the most pernicious disease. Of the childern born in 1999, one-third will contact cancer at some time during their; one-fourth of the male children and one-third of the female children will someday die of cancer. Most of us have had family or friends affected by the disease.In 2002,an estimated 550,000 American died of cancer.

Not surprisingly, researchers are expending a great deal of effort to learn the cause of the disease. Scientists have made a great deal of progress in tha last 20 years using molecular biological techiques,and the rough outlines of understandings are now emerging. We now know that cancer is a gene disorder of somatic tissue, in which damaged genes fail to properly control cell proliferation. The cell division cycle regulated by sophisticated group of protation. Cancer results from the mutation of the genes encoding these protiens.

Cancer can be caused by chemicals that mutate DNA or, in some instances, by viruses that circumvent the cell's normal proliferation controls. Whatever the immediate cause, growth and division. Cell division never stops in a cancerous line of cells. Cancer cells are virtually immortal-until the body in which they reside dies.