Cancer: risk factors, prevention and treatment
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Explainer Video
Summary
Cancer: risk factors, prevention and treatment
In a nutshell
When old or damaged cells die, new cells take their place, these cells can grow and divide. If this division goes wrong, it can result in cancer. Lumps of tissue form a tumour and tumours can be cancerous (malignant), or not cancerous (benign). Tumours can arise in any organ of the body and can sometimes be undetected for years. Cancerous cells can arise from mutations, inheriting cancer-causing genes or even acquired throughout adulthood due to environmental or lifestyle risk factors. Treatment and prevention of cancer are available even for the most aggressive types.
Types of cancers
Identifying the differences in the two types of cancers help healthcare professionals to diagnose patients correctly.
The table below describes the type of cancer and its definition and characteristics:
Benign | Malignant |
| Visible and well-defined borders. | Irregular shape. |
| Non-invasive. | Invasive. |
| Normal cellular growth. | Uncontrolled growth. |
| Divide slowly. | Divide rapidly. |
| Covered in fibrous tissue and does not spread. | Spreads uncontrollably. |
| Non-cancerous tumours. | Cancerous tumours. |
| Stay in the primary location. | Spread via the bloodstream to other areas of the body. |
Malignant cancer formation
| 1. | Normal cells become mutated and malignant cells develop. |
| 2. | Malignant cells rapidly divide by mitosis and invade healthy tissues. |
| 3. | Malignant cells detach from the tumour's primary location and spread to other parts of the body. |
| 4. | The malignant tumour secretes hormone-like chemicals. |
| 5. | This causes blood vessels to grow around the tumour. |
| 6. | Metastatic tumours happen and invade other body parts via the bloodstream. |
| 7. | A malignant cell is able to squeeze through the capillary wall. |
| 8. | The malignant cell divides to produce secondary cancer. |
Curiosity: Malignant cancer uncontrollably spreads, when cancer spreads from the area it originated from to other body parts this process is called metastatic cancer. Metastatic cancer is secondary cancer.
Mutations in genes
Mutation in genes can cause uncontrolled growth of malignant cells. Two types of genes control cell division: the tumour suppressor genes and proto-oncogenes. Acquired mutations are different to inherited mutations as they happen in adulthood and are often caused by lifestyle and environmental risk factors.
TYPE OF GENE | Effects of mutations |
| Tumour suppressor gene | TP genes are tumour suppressor genes that encode the p protein. Over half of cancers involve a deleted or damaged tumour suppressor gene. p mutations are rare but individuals who inherit these mutations have an increased risk of developing different types of cancer in adulthood. |
| Proto-oncogene | The proto-oncogenes produce proteins and regulate cell division, if mutated proto-oncogenes become oncogenes (cancerous) and can uncontrollably divide and spread. |
DNA methylation
Methylation of DNA is important in regulating gene expression, methylation consists of the addition of a methyl group to DNA. This can control if a gene is transcribed, translated and turned into a protein. Errors in DNA methylation can result in the development of tumours. Hypermethylation (too much) or hypomethylation (too little) can result in the growth of malignant tumours. Hypermethylation of proto-oncogenes leads to them function as oncogenes, resulting in the overproduction of proteins, rapid cell growth and cancerous tumours forming.
Genes and environment
There is no single cause for cancer, but there are risk factors that are both genetic and environmental. These risk factors are believed to cause cells to become damaged or mutated. Genetic factors may include cancer being linked to specific inherited genes and people with these genes will therefore have an increased risk of developing cancer.
The table below shows the risk factors involved in cancer development:
Risk factor | Description | Example |
| Genetics | Genetic factors include cancer being linked to specific inherited alleles. | BRCA gene is known to promote breast cancer when mutated. People with this cancer-causing gene have an increased risk of developing breast cancer. |
| Environment | Certain risk factors can affect gene expression and expose DNA to chemical changes in which genes are turned on and off. The excessive use of carcinogens increases the risk of cancer development and influences cell abnormalities. | Exposure to radiation, smoking, drinking alcohol and a poor diet are environmental factors linked to cancer development. |
| Hormones | Hormonal changes can increase cancer risk in patients. | Studies have suggested that oestrogen can contribute to the development of some breast cancers due to increased exposure to oestrogen over an extended period. |
Treatment of cancer
There is lots of research surrounding cancer development and treatment. For more aggressive cancers, the treatment is much stronger. The most common treatments for cancer patients are surgery, chemotherapy, bone marrow transplantation and radiation. The treatment is different depending on the specific mutations and types of cancer. Drugs can also be used to effectively target these specific mutations and treat cancer.
Prevention of cancer
Cancer prevention is information that can benefit both people predisposed to certain cancers and the general public. It is possible to reduce the risk of getting cancer by making healthy choices and maintaining a healthy weight. Making better lifestyle choices such as limiting or stopping alcohol intake and tobacco use can reduce your risk of developing cancer. Wearing sun cream with SPF and covering up in very sunny weather, can help lower the risk of skin cancer. People who have inherited specific alleles that make them predisposed to cancer mutations can also have surgery as a method of prevention.
Example
Women who have inherited the BRCA gene can undergo a mastectomy (breast tissue removal surgery) in order to significantly reduce their risk of developing breast cancer.
FAQs - Frequently Asked Questions
How can a mutation cause cancer?
Mutation in genes can cause uncontrolled growth of malignant cells.
What is charge?
Charge is an inherent property possessed by some particles, it can be positive or negative.
How can hypermethylation cause cancerous tumours?
Hypermethylation of proto-oncogenes leads to them function as oncogenes, resulting in the overproduction of proteins, rapid cell growth and cancerous tumours forming.