Cancer is a class of disease characterized by abnormal growth of cells. Cancer has so many types and is classified by type of organ and cell involved. What causes cancer is a multifactorial trait of pathogenesis. Nothing causes cancer but variably different etiology pattern. On the other hands there is nothing that causes cancer as in leukemia. Lung cancer can occur in a patient who has never ever smoked. The process that causes cancer is called carcinogenesis (oncogenic property). As mentioned above it is said that many factors coordinate and form what causes cancer. There is no single etiology that causes cancer of a specific type; hence preventive measures are also multi sided.
So what factors causes cancer?
What causes cancer can be summed in following headings with explanation: Carcinogens (substance which causes cancer).
A factor causing cancer development is called carcinogens. It’s may be a part of diet or extra diet. Tobacco for example causes cancer of lung. Smoked food causes cancer of stomach. Sun rays causes cancer of skin. Car exhaust causes cancer, tobacco chewing causes cancer in mouth.
Growing makes us prone to some causes of cancer. Age is an important factor that causescancer. Various age groups have various cancer types common in them. Throughout aging process there are genetics mistakes with aging of cells, too. Accidental genetic data happens when cell are dividing while aging. Once damaged, the problem passes to future generations of cell hence age causes cancer.
Genetic mutation in DNA and other genes causes cancer. Various genes are known to suppers the cancer production. But mutated genes are turned off and result causes cancer. In this type some cancer types are known to run in families because of vertical transmission in families. So what causes cancer in mom can cause cancer in daughter, if genetics are involved.
Diet and physical activity:
Diet changes, alcohol intake and physically inactive life add to the pathology that causescancer. Modern era food packaging, additives inclusion, tinned food and addition of nitrates is causing cancer at an alarming rate. The diet causes cancer and we are unaware of the fact because this type of cancer is slowly progressive and is silent in nature. Some foods present in excess or some foods absent completely may also causes cancer.
Sun rays, acid rain, smoke from factories and cars, occupational hazards like silica and asbestos are an important factor that causes cancer. These are important as mass fatality results and these may base their etiology on mutation or cell division disruption process. A natural and manmade radiation also causes cancer mainly by mutation.
It is of immense interest that various kinds of virus are involved in causing cancer, HHV8 cause Kaposi sarcoma in patients with HIV/AIDS. HPV causes cancer of cervix in females. EBV causes cancer in blood that is leukemia. Hepatitis B and C in chronic state causes cancer in liver. These viral infected people are in high risk group for cancer.
Best example is of helicobacter in stomach which causes cancer in stomach. This may be due to various substances production and loss of structure in the infested organ.
People on immunosuppressive drugs due to transplants or otherwise immune-compromised on account of chronic illness and AIDS/HIV etc. are prone to be on high risk for getting cancer. The deranged immune system causes cancer.
Physical trauma or loss of normal structural pattern:
It causes loss of normal structure result in regeneration which may go wrong and metaplasia occurs that further disposes threat that causes cancer.