1. GENETIC-HEREDITARY
Women with the BRAC-1 and BRAC-2 genes are more likely to get breast cancer, have a more aggressive cancer, and get it at a younger age, compared to women without this gene. The inheritance of this gene predisposes women's DNA to damage that ultimately leads to breast cancer. Relatives of those affected should consider genetic screening.
Similarly, colon cancer is common in a subgroup of people with Hereditary Polyposis Coli (HPC). This is a genetic condition that predisposes to multiple (often hundreds) polyps in the bowel. Colonic polyps are widely accepted to be the precursor of colon cancer. People with HPC have a higher risk of colon cancer and they tend to get these cancers at a much younger age. Again, relatives of those affected should consider colonoscopy screening from an early age.
There are other hereditary genetic mutations causing cancer, such as retinoblastoma, an aggressive neurological malignancy in children, and undoubtedly, there are many other cancers caused by as-yet undefined hereditary mutations.
2. ENVIRONMENTAL
Japan has the highest rate of stomach cancer in the world. Japanese emigrants who live in Western societies do not demonstrate an excess risk after living more than ten years in the adopted country. risk of native Japanese. This is significant evidence for an environmental trigger of gastric cancer.
Dietary factors are very important.
Pickled, smoked and spicy foods (high in nitrosamines) increase the risk of cancer in the gastrointestinal tract. A high fat diet, and some micronutrients in very high doses (vitamin A, Vitamin E, vitamin C, selenium) are also potentially carcinogenic.
Meanwhile, Americans who migrate to Japan, eventually inherit' the
3. CHEMICALS
Many chemicals and toxins are potential carcinogens, creating irreparable damage to the genetic material in the nucleus of our cells. Industrial chemicals implicated include; arsenide's, asbestos, benzene, chromiums, naphthylamine, soots, tars and oils, vinyl chloride, tanning agents, agents used in furniture and rubber manufacture. These and other chemicals are risk factors for bladder and testicular cancer amongst others.
Build-up of free radicals in the body will cause DNA damage. Free radicals are extremely reactive by-products of everyday life of our cells - the wear and tear of the body - and have the power to damage DNA. Some chemicals, especially in the context of poor nutrition and immunity, or poor oxygen delivery to tissues, can all lead to the build up of free radicals in cells and their nucleus, causing irreparable DNA damage.
Other toxins including tar found in cigarettes - smoking is by far commonest cause of lung cancer - and asbestos in building products - the cause of the highly malignant, mesothelioma - are established carcinogens. Implicated in esophageal (gullet) cancer, breast cancer, and other cancers is the ubiquitous alcohol (ethanol).
4. VIRAL
The Epstein Barr Virus (EBV), a member of the Herpes family of viruses and the cause of Kissing Fever (Glandular Fever), relates to an aggressive cancer known as Burkitt's lymphoma. Luckily, not everyone exposed to this virus appears at risk most of us come in to contact with this virus at some time, mostly as children. However, Burkitt's lymphoma is extremely rare, particular in Western societies. Other environmental triggers or a rare hereditary predisposing condition is likely required for the carcinogenic effect of EBV, nuclear instability, to manifest itself. Some cancers arise only when specific but multiple different factors combine within a single individual for example Hepatitis C and alcohol in cirrhosis and ultimately liver cancer.
The list of potential viral roles in cancer is significant: Human T-Cell Lymphotropic Virus type 1 (HTLV-1) and lymphoma, HIV and Kaposi's sarcoma are just a couple.
5. IRRADIATION
Ionizing radiation from X-Rays, nuclear isotopes or fallout after nuclear explosions damages and mutates DNA. Even ultraviolet radiation exposure is risky consider sun exposure and skin cancers such as melanoma.
In the 1950's, radiation was used to treat enlargement of the tonsils. These same people some years later began to develop cancers of the neck and throat and at much higher rate than those not subject to this treatment.
6. CHRONIC IRRITATION and REGENERATION
Ongoing chronic trauma, inflammation and regeneration allow for irreparable mutations and faults in the cell's DNA. Occasionally very long-standing venous ulcers undergo malignant transformation. Doctors' call this a Marjolin's ulcer. Ongoing inflammation associated with kidney stones is associated with an increase in the risk of cancer of the ureters or bladder.