CRISPR-Cas9 is a recently developed technological advancement for the addition, removal, or alteration of the DNA of an organism. This new methodology is faster, cheaper, and more accurate than previously existing DNA alteration technologies. Through scientific work done with the biological functions of bacteria, the CRISPR-Cas9 system was created. Bacteria has the ability to identify the DNA structure of a virus and replicate the DNA to create a CRISPR array. CRISPR arrays allow the bacteria to identify the DNA of viruses and produce an enzyme (known as Cas9) that attacks the virus based on the DNA identification. Scientists have been able to use CRISPR-Cas9 in a laboratory setting to retrieve specific sequences of DNA for alteration. This technology is being used to develop new treatment methods for human diseases. The replication of this bacterial function will allow gene therapy procedures to be provided to people in the near future. This technological advancement will improve the lives of cancer and disease patients around the world.