What is Cancer?

Cancers are essentially genetic diseases which are triggered by mutations that lead to abnormal cell growth. Cancer is caused by certain changes to genes that control the way our cells function, grow, and divide. Genes carry the instructions to make proteins, which do a great deal of the work in our cells. Certain gene changes can cause cells to avoid normal growth controls and become cancer. Genetic changes that promote cancer can be inherited from our parents. These changes, called germline changes, are found in every cell of the offspring. Cancer-causing genetic changes can also be obtained during one’s lifetime, as the result of errors that occur when cells divide or from exposure to substances that damage DNA, such as certain chemicals in tobacco, and radiation. There are many different kinds of DNA changes. Some changes affect just one unit of DNA, called a nucleotide. Other changes include larger stretches of DNA and might contain rearrangements, deletions, or duplications of long stretches of DNA. Cancers that are not caused by inherited genetic mutations can sometimes run in families, a shared environment or lifestyle, such as tobacco use, can cause similar cancers to develop among family members. 

https://www.simmonsfirm.com/about-us/giving-back/cancer-institute/