Understanding Genes & Cancer

Your genes tell your personal story and may predict your future

Genes not only direct the development and functions of your body, they can tell many details about what your body has inherited from your parents, what has happened to you in your life to date, your current health condition; they may even predict your future. Amazing! However, it is fair to say that science has a long way to go before we can accurately detect, predict and influence all the health characteristics and problems using genetic information. But there have been great advances in this area, thanks to the human genome project and the monumental amount of research that has been performed in the past 50 years.

Genes impact how your body functions through the epigenome

Genes reside within each cell of your body. They are turned off or turned on selectively by a combination of factors called the epigenome. In a normal situation, for example, specific genes are expressed (turned on) in the lung tissues and allow your lungs to pump air properly; but the same genes are not necessarily expressed (turned off) in your colon, which has a totally different function. The epigenome functions like a computer program. It uses genes, proteins, and other components for instructing the whole body on how to breathe, move, digest, grow cells, etc.

Your epigenome can be altered or influenced by your environment and what you eat. Overtime, this results in slight changes in the program that controls gene expression in certain parts of your body. This, for example, may explain why two apparently identical twins, who are very similar when they are young, tend to differ from one another with age.

Genes act differently in cancer

In cancer, the epigenome is altered, cells proliferate out of control and may start expressing genes in greater or lesser quantities, or they may start expressing genes that are detrimental to the proper functioning of the specific organ. In other situations, when a gene product normally expressed only in a specific organ (like the colon) is found outside that organ, it is an indication that the cells of that organ have escaped their original location, which can usually only occur through cancer metastases or other types of diseases.

The understanding of genes drives personalized medicine

Genes can explain why two women of the same family have different hair color. They can also predict if someone is more susceptible to certain diseases. In fact, by understanding the role of genes and the epigenome, we can assess the risk of a person developing a certain disease, identify the disease early, understand the specific stage of the disease and understand the specific responses to the disease of an individual in order to prescribe the best treatment possible. This is why people are talking about topics such as personalized medicine, pharmaco-genomics, and the like.

Genomic technologies

To detect the activity of genes in specific cells of an organ or a body fluid, we need to access the molecules within the cells. This is done using genomic technologies such as quantitative real-time polymerase chain reaction (qRT-PCR), which is a powerful tool that copies multiple times the very few molecules of the gene or its products that we want to analyze. When the targeted gene has been copied enough times, it can be detected with the appropriate tool. This process is called amplification and detection of gene expression.

In order to detect specific gene expressions that are meaningful to understand your disease, doctors use specialized molecular diagnostic tests that have been proven to be sensitive and specific to your disease. These diagnostic tests are performed on specific tissues or fluids removed from your body either during a surgery or from a biopsy. This new information can help you and your doctor make critical treatment decisions.

Today, only a few useful molecular diagnostic tests have been brought to market and have become the standard of care. But based on the amount of research today in developing new molecular diagnostic tests, this holds the promise that one day, we will have a much better understanding of the complex functioning of human life, and we will be able to more accurately predict and identify diseases, and treat patients with the best therapies possible.

To learn more about molecular diagnostics for cancer, Understanding Cancer Series: Molecular Diagnostics, a document published by the National Cancer Institute, may be a helpful resource.