Cancer's Etiology

Cancer has become a major cause of human deaths in last 20 years. According to American Cancer Society, 7.6 million people died of cancer in 2007. So it’s important to know the etiology of cancer because avoiding the cause of a disease is actually eradicating it.

Cancer is caused by a number of factors:
Industrial environment: It is important as aniline dye industry workers are prone to develop bladder cancer and nickel refining plant workers are at greater risk of developing cancer of nasal sinuses.

UV rays: Fair skinned people are more susceptible to leukemias and especially the open shoes used make people likely to develop acral melanoma.

Chemicals: Hydrocarbons, beryllium, arsenic, cigarette and many others make one prone to develop cancer.

Diet: People who take diet low in Vitamin A can suffer from lung cancer. Nations who drink are also at risk. Black race eat food contaminated with Aspergillus flavus, can develop cancer because of aflatoxin carcinogen substance in their diet.

Drugs: e.g. Immunosuppressive drugs like steroids suppress the immunity of host and increases risk.

Viruses: One of notorious virus of today is Hepatitis B which affects liver and ultimately results in hepatocellular carcinoma.

Parasite: Schistosoma haematobium if infects, causes bladder cancer.

Hormones: One of the commonest causes of breast and uterine endometrial cancer in females is increased levels of estrogen, and, increased levels of dihydrotestosterone (metabolite of testosterone) in males can result in prostate cancer.

Genetic: The genotype may influence the likelihood of one’s developing environmentally induced cancer. This is explained by "oncogenis theory of cancer etiology "that genes for cancer are present normally in body controlling growth and repair but when activated by an environmental or hereditary factor, they may produce cancer. Oncogenes are the abnormal genes and the mutant version of proto-oncogene (normal gene) result in cancer when abnormal single DNA base substitution occurs.

Reference: Robbin's pathology