Genes, Mutations, and Cancer Risk

Our body consists of many genes. A gene is the basic physical and functional unit of heredity. Genes act as instructions to make molecules called proteins that the body needs to function. Our genes are made up of DNA. DNA or deoxyribonucleic acid is the hereditary material in humans and almost all other organisms or in a simple way, the genetic ‘blueprint’ found in each cell. It’s nearly every cell in a person’s body has the same DNA. In the human body, genes vary in size from a few hundred DNA bases to more than 2 million bases. Every person has two copies of each gene, one inherited from each parent. In humans, genes are located on 23 pairs of long strands of DNA called chromosomes. One of each chromosome pair comes from the mother, and the other one comes from the father. Each chromosome can contain hundreds or thousands of genes that are passed from the parents to the child. The genes we were born with are in every cell in our body.

Gene affects inherited traits passed on from a parent to a child, such as hair color, eye color, skin color and height. They also affect whether a person is likely to develop certain diseases, such as cancer. Changes to these genes, called mutations, are important in causing of cancer. Mutations can cause a cell whether to make or not to make proteins that affect how it grows and divides into new cells. Certain mutations can cause cells to grow out of control, which can lead to cancer. Usually several gene changes are needed to becomes a cancer.

Some gene changes that lead to cancer may be inherited from a parent, but mostly are not. It’s only about 5% to 10% of all cancers are thought to be related to an inherited gene change that strongly affects a person’s risk for a certain type of cancer. Most cancers start because of gene mutations that happen sometimes in a person’s lifetime. Sometimes these gene changes have an outside cause, such as exposure to sunlight or radiation, but gene changes can also just be random events that sometimes happen in a cell, without an obvious cause.

These types of acquired mutations only affect the cells that grow from the mutated cell. They do not affect all the cells in the person’s body. This means all the cancer cells will have the mutations, but the normal, non-cancerous cells of the body will not have them as well. This is very different from inherited mutations, which are in every cell in the body, which even the cells without cancer. A variety of agents have the potential to damage DNA, they’re even easy to find around us, such as industrial chemical, natural carcinogens, free radicals, etc. Mutations are generated by DNA damage that escapes the multiple mechanisms for DNA repair. Thus, mutations are not only an indication of cancer but may be central to how cancers evolve.

#Biology