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Cancers have a genomic signature unique to every patient
The interest in and the knowledge of gene expression profiling in cancer medicine has heighten since the completion of the human genome project. However, researchers have cautioned the science of gene expression profiling, in which scientists examine the genetic signature of a cell.
Medical research has focused on developing DNA (genomic) tests to identify various gene expressions, markers and mutations relevant to a person's cancer. The hope was that genetic information would enable researchers to better predict how an individual will respond to various treatment options.
However, when it comes to "predicting" the best treatment for the individual, unlocking the complexities of a person's DNA is not the answer, it is simply a starting point. In fact, a March 16, 2010 study in the Journal of the National Cancer Institute looked at the value of various gene tests and concluded none of the studies showed a clear usefulness.
Genomic tests provide lots of information about a patient's genes. But there are so many sequences in our DNA which influence disease, that attempting to unravel such complexity just produces more and more information without a particularly useful benefit. While genes may provide a recipe, they do not determine the end results and cannot predict how an individual will respond to a specific treatment.
Like the various influences on a flower seed that cause one blossom to turn out differently from another, there are biological processes in the body that affect the development of cancer in each patient and determine how that patient's cancer cells will uniquely react to treatment.
Despite its allure, the "genetic" path is not all that personalized. Treatment based on genetic testing is still a guessing game (trial-and-error). But a treatment regimen based on a "functional profile" - a real-time test of chemotherapy on the actual cancer tissue - can predict with accuracy an individual's response to chemotherapy.
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