Cancer is said to be a genetic disease. This is not referring to the inheritance of cancer from one generation to the next. Although there are examples of variants (mutations) in genes such as BRCA1 which signficantly increase an individual’s risk for developing cancer (for BRCA1, breast and ovarian cancer), this inherited predisposition makes up a small percentage of cancer cases. Rather, cancer is said to be a genetic disease because of the genetic changes which accumulate that enable cancer cells to divide uncontrollably. (For more on this, see here.)
One of the major challenges in treating cancer is that these genetic changes often differ from person to person (even in people with cancers originating from the same tissue) and, as a result, the same treatment is more effective in some patients than others. Already, genetics is being used to guide cancer treatments; for example, there are cancer drugs such as Herceptin which are recommended for a subset of breast cancer patients. However, for many people, this type of “tailored” treatment is not yet available.
Aiming to advance personalized cancer care, a consortium of scientists have embarked on a project called The Cancer Genome Atlas (TCGA) to catalog the genetic changes associated with 20 different forms of cancer. This past week, this group published an analysis of the tumor genomes from nearly 200 individuals with a common form of lung cancer. This is a significant advance in the research process toward developing new tailored treatment options for patients. Additional research is needed to find out which mutations are responsible for tumor growth and, if drugs are available to target these mutations, to determine how effectively they work.
To read more about this study, check out Gina Kolata’s article in the NY Times and Monya Baker’s news report in Nature, which also highlights two studies analyzing tumor genomes from a second form of lung cancer.
Genome sequencing presents new opportunities for improving cancer care, but this path is unlikely to be a simple one. Check out this post from Erika Check Haydn to explore the challenges and limitations in using genome sequencing to personalize cancer treatment.