The KRAS Mutation

Specific genes carry out all the processes that occur in our body. Each gene is encoded by a specific DNA sequence. Over the course of a person’s life, they can acquire a change, or mutation, in the DNA sequence of a specific gene. Researchers have identified mutations in a number of different genes that can each give rise to cancer.

What is the KRAS mutation?

The KRAS gene is needed for normal cell growth.  It is part of a pathway that, when activated by signal, causes the cell to grow and divide. When a mutation occurs in the KRAS gene, cells no longer need a signal to activate the growth pathway, and they grow uncontrollably.  Mutations in the KRAS gene are responsible for causing 20% to 25% of non-small cell lung cancer (NSCLC).  Scientists have identified several specific genetic mutations that occur in the KRAS gene.

  

A. In a non-mutant cell, growth factors (indicated by the green dot) are released when it is time for the cell to grow and divide. The growth factors then bind to and activate a growth factor receptor on the surface of the cell membrane. This receptor activates the KRAS protein, which, in turn, passes the signal along to additional downstream proteins. The signal finally reaches the nucleus of the cell, telling it to begin to grow and divide. B. In a non-mutant cell, when there is no growth factor present, the signaling pathway is shut off. 

  

C. In a cell with a mutant KRAS protein, KRAS is active even in the absence of growth factors.  The mutant KRAS continues to signal to the cell to grow and divide. D. Inhibiting the mutant KRAS protein by using targeted therapies and/or immunotherapies can turn off the growth signal.