The Little-Known Genetic Mutation Leading to Cancers

Name: Leeza Petrov
Source: http://discovermagazine.com/2014/dec/16-true-believer
Date: Published in the December 2014 issue of Discover Magazine
Author: Linda Marsa

Summary: Dr. Joanne Weidhaas is a doctor that is raising awareness of a mutation in a gene known as KRAS, which has been linked to more cancers than any other known mutation. The KRAS-variant was found in 1/4 of all cancer patients and in over half of all people that develop multiple cancers. Patients that carry the KRAS-variant tend to get aggressive and recurrent ovarian, breast, head and neck, pancreatic, and lung cancers.
Weidhaas and her parter, Slack, first discovered the variant in 2008, and developed a diagnostic test that would take saliva or blood samples and test for the presence of the KRAS-variant. Their results showed that about 1 in 20 people in the population carries it. To contrast, the commonly known breast cancer causing mutations, BRCA1 and BRCA2 are found in approximately 1 in 400 people.
Ordinarily, KRAS is a gene that regulates cell growth and the cell life cycle, which is essential for proper function of an organism. However, certain mutations to the KRAS gene and other similar genes lead to the overproduction of their specific protein, resulting in the disruption of the cell cycle and in some cases, cancer.
In KRAS-variant patients, the microRNA that was normally used for transcription couldn't attach to the KRAS gene to regulate its production of protein. The extra protein led to unchecked cellular division and cancer.

Relevance: This study on a deadly mutation of a gene in the human body pertains to our study of molecular genetics in term 2. We learned about the basic types of mutations on both a genomic level (eg - substitution, insertion, deletion of a base pair or base pairs) and on a chromosomal level (eg - inversion, duplication, translocation of part of a chromosome). This is a specific example of a mutation that leads to serious damage because the gene in which this mutation occurs happens to control cell division. We also learned about transcription and translation and the process of making proteins from genetic information found in DNA. Because of this mutation, the RNA cannot properly transcribe the code, and therefore the entire process of building proteins is disrupted. Proteins (as we learned in both unit 2 and unit 5) are essential to the function of a cell's life, and if a cell cannot make a certain protein (depending on the importance of the protein), the consequences can be devastating. This KRAS-variant mutation has certainly led to devastating consequences in the lives of the people who suffer from cancers caused by this mutation.