Somatic Mutations leads to Cancer

“Somatic Mutations or Body Mutations may lead to cancer”.

Forewords

This blog is intended to provide a general understanding and explore biological importance.

Definition

Somatic mutations are genetic alterations that occur in the DNA of body cells or non-reproductive (somatic) cells, which make up the majority of cells in the body. These mutations are not inherited but are acquired during a person’s life, often due to environmental factors (physical, chemical, or biological factors), ageing, or errors in DNA replication. Somatic mutations occur in genes or DNA that regulate cell growth and division, and they may lead to the development of cancer.

General view of mutations

Various factors can contribute to the occurrence of somatic mutations, including exposure to carcinogens (e.g., tobacco smoke, UV radiation), chronic inflammation, certain viruses, and cellular oxidative stress. However, it is essential to note that not all somatic mutations lead to cancer. Many of these mutations are harmless, and some can even be repaired by the cell’s DNA repair mechanisms.

Environmental factors causing mutations

• Physical mutagens

• Ionizing Radiation such as X-rays
• gamma rays, and radioactive materials
• Ultraviolet (UV) Radiation (UV rays) comes from sunlight and artificial sources like tanning beds
• Non-Ionizing Radiation includes radio waves, microwaves, and extremely low-frequency electromagnetic fields that can damage DNA
• High-Energy Particles, heat, and physical stress may also lead to the development of cancers in the body.

• Chemical mutagens

These mutagens originate from chemicals that can alter the DNA sequence, leading to changes in the genetic information, which may result in various abnormal cell growth called cancer. Examples include:

1. Polycyclic Aromatic Hydrocarbons (PAHs) – from smoking, vehicle exhaust, and charred food.
2. Aromatic Amines – Found in some dyes, plastics, and rubber products.
3. Nitrosamines – Found in preservatives in processed meats.
4. Benzene – An industrial chemical, including plastics, rubber, and gasoline.
5. Formaldehyde – This chemical is used in building materials, household products, and some industrial processes.
6. Vinyl Chloride – Used in the production of PVC (polyvinyl chloride) plastics.
7. Ethylene Oxide – A chemical used for sterilization and as a raw material in various industries, etc.
8. Intercalating Agents: Certain chemicals used in laboratories, such as ethidium bromide, Acridine Orange, Doxorubicin, etc., distort the DNA structure and lead to errors during replication or repair.
9. Nitrous Acid: Found especially in cured and processed meats, as they are sometimes used as preservatives, reacts with DNA, causing chemical changes that can lead to the mispairing of nucleotide bases during replication.
10. Aflatoxins: These naturally occurring toxins are produced by certain moulds (normally grown on groundnut seed nuts stored in warm and humid conditions- remember those seeds are looking shrunken; the taste is bitter), such as Aspergillus species. They can be present in contaminated food and have been associated with mutagenesis and an increased risk of liver cancer.

• Biological mutagens

1. Viruses: Retroviruses, such as HIV, are able to integrate their RNA into our cell’s DNA using the enzyme reverse transcriptase and alter the genetic makeup of the infected cells. As a result, the genes may get another abnormal potency to divide again and again, causing the birth of cancer.
2. Transposons: These are known as “jumping genes capable of moving from one location in the genome to another in our body. “They make up about 10% of the human genome, with over one million copies scattered throughout the DNA. They can disrupt the gene/DNA or able to create new exons (functional genes- they may be cancerous).
3. Error-Prone DNA Polymerases: Unfortunately, we too have had some specialized unwanted polymerases in our body that can initiate gene mutations during replication.
4. Reactive Oxygen Species (ROS): These are formed from the incomplete utilization of Oxygen (partial reduction of Oxygen), especially in the mitochondria during the Electron Transport Chain (ETC) and superoxide radicals (O2•-) by combining with some electrons. These are highly reactive and provoke oxidative damage to DNA and other biomolecules, leading to mutations and cellular dysfunction.

Cancer propagation and accumulation in the body!

Cancer is a complex group of diseases characterized by uncontrolled cell growth and the ability of cells to invade surrounding tissues. Somatic mutations in certain genes can disrupt the normal mechanisms that regulate cell division, leading to the formation of a tumour. These mutated cells can then grow uncontrollably and spread to other parts of the body through a process known as metastasis.

Q: In what way do the mutagens change or damage the DNA and cause mutations?

Carcinogenic agents (cancer-causing factors) show adverse effects on our genetic makeup (DNA) in multiple ways at the molecular level and damage.

There are various types of somatic mutations that can contribute to cancer development. Some of the common types include:

1. Point mutations: These involve the replacement of a single DNA base with another, potentially leading to changes in the protein produced by the gene.
2. Deletions and insertions: These mutations involve the loss or addition of one or more DNA bases, disrupting the normal reading frame of the gene.
3. Gene amplification: In this type of mutation, certain genes are duplicated multiple times, leading to an increased expression of the corresponding proteins and promoting uncontrolled cell growth.
4. Chromosomal translocations: These mutations involve the rearrangement of genetic material between two non-homologous chromosomes, leading to fusion genes that can drive abnormal cell behaviour.

Conclusion *

Understanding the genetic basis of cancer has led to aware people to implement a healthy way of life with appropriate precautions and significant advancements in cancer research and personalized medicine. By identifying specific somatic mutations driving a person’s cancer, targeted therapies can be developed to inhibit the specific mutated proteins, potentially leading to more effective and less harmful treatments.

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@ Consult your healthcare professionals for personalized information about cancer, its causes, risk factors, prevention, and treatment options.”