Cancer is a complex term used for a large group of diseases with many possible causes. Cancer is caused by the rapid division of abnormal cells and spread to other tissue and organs. One of the leading causes of death in the world is cancer.
Cancer cells don’t act or look like the normal cells from which they originate. Thus in cancer cells, changes occur in key genes, thus causing the normal cells to act abnormally. These changes are the result of mutations to the DNA in the cells. As there are different things which can cause mutation, similarly there is a large number of causes of cancer.
Common causes of cancer
The basic cause of cancers is DNA damage and genomic variability. However, minority of cancers occur due to hereditary genetic mutations. But most cancers are linked to environmental, lifestyle, or behavioral exposures. Most common causes of cancer are as follows;
- Smoking and tobacco
- Diet and physical activity
- Sun and other types of radiation
- Viruses and other infections
- Environmental exposure
Smoking and tobacco
Smoking causes cancer by damaging our DNA and key genes which protect us against cancer. The chemicals found in cigarettes and tobacco are in involved in DNA damag. These chemicals include polonium-210, benzene, nitrosamines, and benzo(a)pyrene. Other chemicals like arsenic and nickel present in tobacco interfere with pathways involved in fixing damaged DNA. This makes it even more possible that damaged cells will ultimately turn cancerous.
Chemicals present in cigarette smoke enter our bloodstream, thus affecting the entire body. Chemicals in cigarette smoke also make it even harder for smokers to neutralize or eliminate toxins from the body. Therefore, this can make their immune systems less active too. That is why smoking causes many diseases, including at least 15 types of cancer, various lung diseases, and heart diseases.
Smokers have a much greater risk of lung cancer than non-smokers, whatsoever the type of cigarette they smoke. Due to which lung cancer survival is one of the lowest of all cancers, mainly caused by cigarette smoking. Research has shown that for every 15 cigarettes smoked there is a DNA change causing a cell to become cancerous. So, it is better to give up smoking sooner rather than later.
Diet and physical activity
Diet directly affects your physical health, and nutrition is a chief factor in whether or not you develop any disease. Poor dietary habits can impair our daily health and comfort and may reduce our ability to lead an enjoyable life.
Stomach cancer is 5-6 times greater among Japanese men due to the intake of fermented foods. Breast cancer is 20 times higher among American women, credited to the high-fat American diet. Alcohol is a big promoter of carcinogenesis in humans, as is asbestos. As drinking alcohol frequently may increase the threat of many different cancers.
Physical inactivity is a prime cause of many chronic diseases. So, staying at a healthy weight is very important to reduce the risk of cancer and other chronic diseases. As excess weight can cause the body to produce and circulate more insulin and estrogen. Therefore, these hormones may stimulate cancer growth. Being overweight or obese increases the risk of cancers, including breast, esophagus, pancreas, colon and rectum, endometrium, and kidney, among others.
Physical activity and exercise are the key ingredients of a healthy life. Proper physical activity can reduce your risk of lung, bowel and womb cancer. It may also help prevent breast cancer. And physical activity does not just reduce your risk of cancer but it has many other benefits as well.
It can help:
- Control your weight.
- Reduce your risk of heart disease.
- Reduce your risk of diabetes.
- Strengthen your bones and muscles.
- Improve your mental health and mood.
- Increase your chances of living longer.
Sun and other types of radiations
Some offensive cancers are linked to radiation exposure, including both ionizing and non-ionizing radiation. Furthermore, the immense majority of non-invasive cancers are non-melanoma skin cancers that are due to non-ionizing ultraviolet radiation.
Non-ionizing radiofrequency radiation coming from electric power transmission, mobile phones, and other alike sources have been designated as a possible carcinogen by the World Health Organization’s International Agency for Research on Cancer, however, the link still remains unproven.
Any radiation exposure can increase the risk of cancer according to the prevalent model. Usual providers to such risk include occupational exposures, natural background radiation, nuclear accidents, medical procedures, and many others.
Furthermore, continued exposure to ultraviolet radiation coming from the sun may lead to melanoma and other skin distortions. Strong evidence founds that ultraviolet radiation, particularly the non-ionizing medium wave UVB, as the cause of most non-melanoma skin cancers, which are the common forms of cancer in the world.
Viruses and other infections
There are some infections which can cause long-term inflammation in different parts of the body. Infection is the fourth most significant risk factor for cancer mortality in the advanced world. Hence, this can cause changes in the affected cells and also in nearby immune cells, which can ultimately lead to cancer.
In addition to radiations and chemicals, another cause of mutation is viruses. Viruses are very small organisms which can infect the cells of other animals or plants. Humans are susceptible to many different viruses. Hence, viruses are not the same as bacteria though both can cause many human diseases.
Viruses can disturb cell behavior in many different ways.
- They can cause DNA damage by inserting their genomes into the host DNA. This integration can disrupt many important regulatory genes.
- The viruses may comprise their own genes which disrupt the cellular regulation. This process is advantageous to the virus.Consequently, it allows rapid production of viral progeny but can be seriously damaging to the host.
- Some viruses carry altered versions of genes which they have picked up from previous host cells. These altered genes could not function properly. When these genes are inserted into a new host, they usually cause dysregulation, thus leading to cancerous growth.
Through their mutagenic activity, viruses play a substantial role in the development of certain cancers in different animals, including humans.
Many potential environmental factors are also involved in the initiation, elevation, and advancement of cancer. Leatherworking, nickel refining, and woodworking have also been related with an increased risk of particular cancers due to disclosure to carcinogenic chemicals.
Exposure to mustard gas which was used as a chemical warfare agent in World War I. Hence, this gas has been linked with a higher risk of lung and respiratory tract cancers due to its mutagenic properties.Thus, the impact of numerous environmental aspects can be reduced by making healthy lifestyle choices.
The risk of getting cancer from exposure depends upon the length of exposure to environmental pollutants and type of carcinogen. There are several different substances which can act as carcinogens. Here are some important environmental carcinogens and cancer risk factors;
- Coal Tar and Coal-Tar Pitch
- Coke-Oven Emissions
- Ethylene Oxide