What is Cancer and How Causes it?

Cancer is the one of the most dangerous diseases in  the world in recent time. According to the World Cancer Report from WHO (WORLD HEALTH ORGONIZATION) that  In many countries, more than a quarter of deaths are attributable to cancer. In 2000, 5.3 million men and 4.7 million women developed a malignant tumour and altogether 6.2 million died from the disease.and the Global cancer rates could increase by 50% to 15 million by 2020 in all over the World.

                so It  is our primary Responsibility to know what is Cancer ,types of Cancer and steps for prevent it. 

What is Cancer?

Cancer is a class of diseases characterized by out-of-control cell growth. 

• There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected.
• Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.

 

How causes cancer?

Cancer arises from one single cell. The transformation from a normal cell into a tumour cell  is a multistage process, typically a progression from a pre-cancerous lesion to malignant tumours. These changes are the result of the interaction between a person's genetic factors and three categories of external agents , including:

• physical carcinogens, such as ultraviolet and ionizing radiation;

• chemical carcinogens, such as asbestos, components of tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking water contaminant); and

• biological carcinogens, such as infections from certain viruses, bacteria or parasites.

WHO, through its cancer research agency, International Agency for Research on Cancer (IARC), maintains a classification of cancer causing agents.Ageing is another fundamental factor for the development of cancer. The incidence of cancer rises dramatically with age, most likely due to a build up of risks for specific cancers that increase with age. The overall risk accumulation is combined with the tendency for cellular repair mechanisms to be less effective as a person grows older.