Cancer is Hereditary – Fact or Myth
We will explore if cancer is hereditary. However, let us explore what is cancer and what are its symptoms. Cancer is a set of diseases involving abnormal growth of cells. It has the potential to spread to various parts of the body.
Cancer cells divide uncontrollably and can destroy body tissues. There are more than 100 types of cancer that can affect human beings. A few examples are breast cancer, colon cancer, skin cancer, and prostate cancer. Cancer symptoms depend on the type of cancer. Cancer Treatment can involve chemotherapy, radiotherapy and surgery.
Symptoms of cancer
In the initial stages of cancer, there are no symptoms. Few signs start to appear as the mass of cells ulcerates. A lump in the skin can be one of the earliest signs of cancer. Few symptoms are specific to the type of cancer.
Local symptoms also occur due to the tumor. People with cancers in the soft tissues and lymph nodes have lumps. In the case of lung cancer, the bronchus can be blocked, resulting in coughing. Colorectal cancer may result in the blockages of the bowel. Symptoms like fatigue, coughing up blood, and weight loss are also noticed in most cases of cancer.
Influence of Heredity on Cancer & other Facts
Cancer is hereditary or not, it is unwelcomed worldwide. It results in several deaths every year. Thus, the patients must select only the best cancer treatment. Below are a few facts about cancer:
- About 22% of cancer deaths are caused due to tobacco use
- Approximately 10% of cancer deaths are due to obesity, lack of physical activity, poor diet, or excessive consumption of alcohol.
- Only 5-10% of the cases of cancer are due to genetic defects inherited from the parents.
- About 14.1 million new cases are reported every year.
- In 2015, approximately 90.5 million people had cancer.
How can genes cause cancer?
A structure called the nucleus is present inside every cell of the body. It is the control center of the cell. Within the nucleus are 23 pairs of chromosomes comprising genes. Genes are the coded messages that instruct the cell on how to behave.
All types of cancer are developed because of a fault or a mutation in one or more genes in a cell. In most cases, a gene becomes cancerous if it has 6 or more faults. The cell might stop functioning properly due to these faults. It might become cancerous and divide uncontrollably.
The majority of the gene faults develop during the lifetime of a person. The gene faults might happen due to random mistakes when the cells are dividing. However, some (5-10%) might be inherited from the parents. The gene faults might also occur due to exposure to cigarette smoke or other carcinogens. These genes are not inherited and cannot be passed from the parent to the offspring.
Cancer is Hereditary – Inheriting faulty cancer genes
Some faulty genes that might increase hereditary risks of cancer can be passed from the parent to the offspring. These genes are called inherited cancer genes. These make cancer hereditary.
It happens when there is a fault in the sperm or egg cell. In this manner, the gene fault can be passed on to the children. The child inherits genes from both parents. Thus, some children will have a gene and an increased chance of developing cancer while some won’t.
Being born with an inherited faulty gene does not mean that the child will develop cancer. However, the risk of developing cancer and showing cancer symptoms increases.
Are cancers due to inherited genes common?
Most cancers are not hereditary. Cancers caused due to gene changes caused by radiation and other factors are more common than cancers caused due to an inherited faulty gene. Most cancers are caused due to environmental factors and not hereditary ones.
Less than 0.3% of the populations carry a genetic mutation that has a detrimental effect on the risk of developing cancer. These genes cause less than 3-10% of cancer.
Types of Hereditary Cancer
Few types of hereditary cancer, which inherited gene mutations have been discovered are –
- Adrenal gland cancer
- Bone cancer
- Breast cancer
- Fallopian tube cancer
- Ovarian cancer
- Prostate cancer
- Skin cancer
- Testicular cancer
Other factors that can cause cancer
Most cancers are due to lifestyle and environmental factors. Environmental factors refer to any factor that is not genetically inherited. They can be lifestyle or behavioral factors. This is where the importance of preventive care comes into play. Common factors that lead to cancer death are tobacco (around 25-30%), obesity (30-35%), radiation, and infections (approximately 15-20%). Below are the causes that could lead to the development of cancer –
- Chemicals: Exposure to carcinogens is linked to the development of specific types of cancer. For example, tobacco smoke is a cause for 90% of lung cancer cases.
- Diet and physical activity: Excessive body weight is linked to the development of many cancers. A high-salt diet might result in gastric cancer.
- Infection: Around 18% of cancer deaths are linked to infectious diseases.
- Radiation: Radioactive material and exposure to UV radiation increase the risk of cancer.
- Physical agents: Some agents cause cancer through their physical effects. Continuous exposure to asbestos can result in mesothelioma.
Thus, most factors that might result in developing cancer are environmental rather than hereditary. However, some cancers are hereditary.