ENVIRONMENTAL FACTORS AND CANCER

                      Friends, this is a small post about cancer. Cancer afflicts all communities worldwide, approximately 10 million people are diagnosed with cancer and more then 6 million die of the disease every year. Cancer may be regarded as a group of diseases characterized by an abnormal growth of cells ability to invade adjacent tissues and even distant organs, and the eventual death of the affected patient if the tumour has progressed beyond that stage when it can be successfully removed.
        Now I am writing about environmental which causes cancer. Today our lifestyles are changed. Environmental factors are generally held responsible for 80 to 90 percent of all human cancers. The major environmental factors identified so far include:
     Tobacco :

              Tobacco in various forms of usages like smoking and chewing , is the major environmental cause of cancers of lung, larynx, mouth, pharynx, oesophagus, bladder, pancreas and probably kidney.
    Alcohol :

      Alcohol contributed to about 3 percent of all cancer deaths. Excessive intake of alcoholic beverages is associated with oesophageal and liver cancer. Some recent studies have suggested that beer consumption may be associated with rectal cancer.
   Dietary Factors :

  
         Dietary factors are also related to cancer. Some examples are - smoked fish is related to stomach cancer, dietary fiber to intestinal cancer, beef consumption to bowel cancer and a high fat diet to breast cancer. A variety of other dietary factors such as food additives and contaminants have fallen under suspicion as causative agents
    Occupational Exposures :

          Occupational exposures are usually reported to account to 1 to 5 percent of all human cancers. These include exposure to benzene, arsenic, cadmium, chromium, vinyl chloride, asbestos, polycyclic hydrocarbons...etc. Many others remain to be identified. The risk of occupational exposure is considerably increased if the individuals also smoke cigarettes.
       Viruses :

           An intensive search for a viral origin of human cancers revealed that hepatitis B and C virus is casually related to hepatocellular carcinoma. The related risk of Kaposi's sarcoma occurring in patients with HIV infection is so high that it was the first manifestation of the AIDS epidemic to be recognized. Non-Hodgkin's lymphoma, a cancer of the lymph nodes and spleen is a late complication of AIDS. The Epstein-Barr virus (EBV) is associated with 2 human malignancies, viz. Burkitt's lymphoma and nasopharyngeal carcinoma. Cyto megalo virus (CMV) is a suspected oncogenic agent and classical Kaposi's sarcoma is associated with a higher prevalence of antibodies to CMV. Human papilloma virus (HPV) is a chief suspect in cancer cervix. Hodgkin's disease is also believed to be of viral origin.
    Parasites :

           Parasitic infections may also increase the risk of cancer. Example, schistosomiasis in Middle East producing carcinoma of the bladder.
        Lifestyles And Habits :

             Our lifestyles changed. Habits and lifestyles of people which may be associated with an increased risk for certain cancers. Some examples are the demonstrated association between smoking and lung cancer, tobacco and betel chewing and oral cancer..etc.
    Others :

       There  are numerous other environmental factors such as sunlight, radiation, air and water pollution, medications and pesticides which are related to cancer