Tobacco cancer

Resource for Tobacco cancer and fun search portal . Continue for our current list for the Tobacco cancer

Love Poems, Love Calculator

Arts And Entertainment

Health And Fitness

Home Based Business

Self Improvement

Dating, Love, Sexuality

Relationships

Funny Pictures

MSN Nick Names,Display Pictures,Emoticons,Background

Cancer is, ultimately, a disease of genes. Typically, a series of several mutations is required before a cell becomes a cancer cell. We distinguish between oncogenes, which promote cancer when "switched on" by a mutation, and tumor suppressor genes, which prevent cancer unless "switched off" by a mutation. These mutations can have various causes: radiation or chemicals called carcinogens; some inherited predisposition is not uncommon; some viruses that can cause cancer have also been described. Usually, they carry in their genome some oncogene or tumor suppressor inactivating gene. In about 15% of all cancers, viruses seem to play a role; Bacteria, like Helicobacter pylori, also induce carcinogenesis by a process of chronic inflammation. Finally, damage by free radicals, which are a natural by-product of oxygen metabolism, can cause mutations in the DNA.

Cancers are capable of spreading through the body by two mechanisms: local invasion and distant metastasis. Invasion refers to the direct migration and penetration by cancer cells into neighboring tissues. Metastasis refers to the ability of cancer cells to penetrate into lymphatic and blood vessels, circulate through the bloodstream, and then invade normal tissues elsewhere in the body. Cancer is most deadly when it metastasizes.

In medicine, cancer is a general term for any of a number of different diseases where some of the body's own cells divide in an uncontrolled manner. The resulting new cells can form a malignant tumor (a neoplasm) or propagate throughout the body.