Cancer is a disease characterized by the mutation of normal cells into cancer cells that divide uncontrollably and destroy the normal body tissue. The cancer cells invade the neighboring tissues and often spread throughout your body to form metastasis in distant organs.
This post discusses what causes cancer, why some people get cancer, how the normal cell turns into a cancer cell, and the risk factors that make you more likely to get cancer. Genetics has a major role to make you cancer-prone.
Cancer is the second-leading cause of death in the world after cardiovascular disease. Cancer statistics about its prevalence are alarming. Now, however, the survival rates are improving for certain types of cancer.
This is mainly due to cancer screening and treatment reaching out to a larger population and the subsequent early detection and treatment of this disease.
There is no single cause for cancer. Research believes that it is the involvement of several factors that act together to give you cancer. These factors could be genetic, environmental, or the characteristics of the individual’s body.
How is cancer caused?
The following presentation makes it very simple for you to understand what causes cancer and how the normal cell changes into a cancer cell.
To understand how you get cancer, you have to understand the cellular changes that take place and how a normal cell is converted into a cancer cell.
First, understand that cancer originates in a cell.
Every cell contains DNA (deoxyribonucleic acid). DNA is the molecule inside cells that contains the genetic information responsible for the characteristics, development, and function of an organism or individual. DNA molecules pass this information from one generation to the next.
When the DNA structure of the cell gets altered or the DNA of the cell undergoes mutation (a permanent change in the DNA sequence of the gene), you are looking at cancerous changes.
This mutation, which results in cancer, is caused by what we call mutagens. Since these mutagens cause cancer, they are called carcinogens.
Carcinogens are divided into three major categories:
- Chemical carcinogens (including those from biological sources) such as asbestos, nickel, cadmium, radon, vinyl chloride, benzidine, and benzene.
- Physical carcinogens such as hard and soft materials, fibrous particles, nonfibrous particles, and gel materials,
- Oncogenic (cancer-causing) viruses are suspected of causing cancer in animals and humans. Examples include human papillomaviruses, the Epstein-Barr virus, and the hepatitis B virus.
Cancer cannot be transmitted from one person to another except rarely, through pregnancy from mother to baby and by organ transplant surgery from donor to recipient.
Risk factors that cause cancer
We do not know exactly why one person develops cancer and another doesn’t. Research reveals that certain risk factors make you more likely to get cancer. However, yet many people with cancer are not associated with any of these risk factors. Research goes on and still many answers remain unanswered.
1) Genetic factors
Approximately 5% to 20% of all cancers are due to hereditary causes. This type of cancer is also called hereditary cancer or familial cancer. It means that a person is born with a genetic mutation that predisposes him to the development of cancer.
You can inherit this genetic mutation either from the father’s or mother’s side or from both. Also, examine the medical history of your current relatives to determine about you being prone to cancer or not.
Such families carry mutated genes, BRCA1 and BRCA2, which make them more prone to
Some clues that tell you if cancer runs in the family include:
- Having multiple relatives with cancer on the father’s or mother’s side of the family especially if diagnosed at a young age.
- Having one person in the family with multiple tumors in the same organ
2) Exposure to radiation
Repeated and over-exposure to radiation predisposes to causing cancer. Too much radiation can cause damage to the tissues by changing the structure of the cell and causing damage to the DNA of the cell.
This may be due to treatment by repeated doses of radiation for cancer itself. This can also happen when a radiologist or an x-ray technician who is exposed to radiation of x-ray regularly does not take precautions to protect himself against radiation.
Exposure to radiation increases the risk of developing leukemia, cancers of lungs, breast, thyroid, stomach, testicles, etc. The incidence of cancer due to radiation is 10%.
3) Exposure to ultraviolet rays of sunlight
Exposure to ultraviolet rays of the sun or tanning booths or sun lamps can cause melanoma or other forms of skin cancers.
Most skin cancers are caused by over-exposure to the UV rays in sunlight. This is a proven cause of basal cell carcinoma and squamous cell carcinoma, which often appear on exposed areas of the skin. If detected early, these skin cancers are almost always curable.
If you are in an occupation that requires unusual exposure to the sun, you could protect yourself with proper headgear and clothing. Using sunscreens will also be helpful.
4) Certain chemicals
Long-term exposure to chemicals (as in an occupational hazard) can cause cancer, especially of the lungs due to inhalation of chemical vapor or direct contact. Such chemicals include pesticides, asbestos, benzene, nickel, uranium, nickel, glass wool, rock wool, and radon.
1,4-dichlorobenzene (DCB) has been used for years during the past in the manufacture of air fresheners and deodorizers for use in public toilets, homes, and offices. It can cause liver cancer and it is therefore banned.
Similarly, chemical compounds called azodyes release cancer-causing chemicals called aromatic amines. Since 2003, therefore, they are restricted for use in textile and leather articles.
5) Certain viruses, bacteria, and parasites
Infections caused by certain viruses, bacteria, and parasites cause cancer.
- Viruses that cause cancer are called oncovirus. These viruses include those that cause hepatitis B and C, HPV virus, and Epstein Barr virus, which causes infectious mononucleosis.
- Bacteria such as H. Pylori, which are responsible for stomach ulcers, can cause stomach cancer.
- Parasites such as liver flukes and Schistosoma haematobium can cause squamous cell carcinoma of the bladder.
The worldwide average of cancer due to these infections is 18%. It varies wildly among various regions. For example, the incidence in Africa is 25% while in the developed countries, it is less than 10%.
6) Lifestyles habits
- Diets that cause cancer are those that are low in vegetables, fruits, and whole grains and high in red or processed meats. A high salt diet causes gastric ulcers, as is seen in Japan. The habit of chewing betel nut can cause oral cancer. Aflatoxin B1 is a highly toxic carcinogen, which contaminates crops and the milk of animals that are fed these contaminated feeds. Aflatoxin B1 causes cancer of the liver. Studies indicate that eating red or processed meat increases your risk of breast, colon, prostate, and pancreatic cancer. This is possibly due to the presence of carcinogens in foods cooked at high temperatures.
- A sedentary life without physical activity can cause cancer due to its adverse effects on your body’s immunity and endocrine system. Research has shown that being sedentary can increase your risk of cancer. Experts believe that poor circulation and higher insulin levels in the blood due to physical inactivity can contribute to cell growth in cancer. The most widely reported cancers in physically inactive people are cancers of the colon, endometrium, and breast.
- Obesity is a contributory factor to many types of cancer. Being overweight has been associated with 14% to 20% of cancer deaths. Large cohort studies have established the link between obesity and cancer.
7) Hormonal imbalance
Being exposed to higher levels of estrogen and progesterone increases the risk of breast cancer in women. Similarly, higher levels of testosterone are associated with prostate cancer in men. These higher levels of hormones may be due to hereditary traits, obesity, or hormone replacement therapy.
8) Smoking causes cancer
Smoking is the leading cause of cancer. Tobacco smoke contains more than 50 carcinogens and is the cause of cancer deaths in 30% of cancer cases in the developed countries. Ninety percent of lung cancers are caused by tobacco smoking.
Smoking can cause cancer of the lung, mouth, throat, esophagus, bladder, and pancreas. About 10% of smokers die of cancer and the heavier you smoke greater is the risk of cancer.
9) A deficient immune system
Persons who are Human Immunodeficiency Virus (HIV) or AIDS positive have a higher incidence of cancer, thus indicating that poor immunity leads to cancer. Not only AIDS but other disorders also, which lower immunity are associated with a greater incidence of cancer. Examples include common variable immunodeficiency and IgA deficiency.
10) Alcohol can cause cancer
According to the Centers for Disease Control and Prevention, drinking alcohol raises your risk of developing six kinds of cancer.
An enzyme called alcohol dehydrogenase (ADH) in the liver breaks down most of the ethanol in alcohol to acetaldehyde, which is a known carcinogen. Acetaldehyde damages the DNA of the normal cell and prevents the cells from repairing the damage.
This stimulates cancerous cells to grow and increase the rate of cell reproduction. This higher speed of cell division leaves no time for the repair enzymes in the body to repair the damaged DNA of the cell. As a result, this increases the chances of normal cells being mutated into cancer cells.
All types of alcoholic drinks including wines, beers, and hard liquor, are linked with cancer.
10) Increasing Age increases cancer risk
Age is the biggest single risk factor for the development of cancer. Advanced age increases your risk of cancer due to the reduced efficiency of the immune system caused by aging. As a result, this disturbs the repair of the damaged cells. Accumulation of these damaged cells can cause a mutation to occur.
The risk increases considerably after the age of 50. Half of all cancers are diagnosed at the age of 66 and above. According to the National Cancer Institute, 25% of new cancer cases diagnosed are in the age group of 65 to 74 years.