A growing area of cancer research, called cancer genome research, studies the differences in genes found in tumors to understand which ones are important. In cancer genome research, researchers collect thousands of samples from all types of tumors to find out a tumor’s genetic “fingerprint.” Different genes are involved in different tumor types, and understanding what genes are important to the development of cancer may lead to improvements in detecting, diagnosing, and treating cancer.

The human genome

To better understand cancer genome research, a basic knowledge of genes and genomes helps.

Each cell in the human body contains about 20,500 genes. Genes are the instructions, or blueprints, that tell our bodies how to grow and develop. They are arranged in pairs and are made of genetic material called DNA.

All of a person’s genes together are known as a genome. Genomics is the study of what these genes do and how they interact with each other. In 2003, researchers identified the sequence (order) of the genome in the human body as part of the Human Genome Project.

Cancer genomes

All of the genes in a cancer cell are known as the cancer genome, and cancer genomics is the study of the cancer genome.

Cancer begins when normal cells begin to change and grow uncontrollably, forming a mass called a tumor. In a cancer cell, genes mutate (change) in ways that are harmful.

How a specific cancer cell behaves depends on which gene mutations it has. For instance, some cancer cells simply divide and produce more cancer cells, and the tumor stays where it began. Other tumors are able to spread to other parts of the body.

Mapping the cancer genome

Studying the cancer genome, often called “mapping” the cancer genome, helps researchers understand the mutated genes that lead to cancer. This information will help answer many important questions about how to detect cancer and how to best treat each patient.

For example, by identifying mutated genes that cause cancer to develop or spread, researchers hope to develop drugs that target those specific genes to stop the cancer’s growth. Learn more about targeted treatments. Also, identifying the genes responsible for cancer helps researchers and doctors develop tests to detect cancer earlier.

Researchers have already identified many mutated genes in breast cancer, colon cancer, melanoma, and other cancers that have led to the development of tests that can determine which treatment will be the most effective. Discoveries in cancer genomics have also helped identify several new treatments that target mutated genes. For example, the drug imatinib (Gleevec) treats chronic myeloid leukemia, gastrointestinal stromal tumors (GIST), and several other types of cancer. Trastuzumab (Herceptin) is another example of a drug that works in treating breast cancers with a specific genetic mutation that causes tumors to have too much of a protein called HER2.

Many scientists are working to create a map of the cancer genome that details every gene mutation in cancer. One of the biggest efforts underway to map the cancer genome is The Cancer Genome Atlas (TCGA) project. This project was started more than three years ago by the National Cancer Institute and the National Human Genome Research Institute.

As part of TCGA, researchers are collecting tissue samples from patients treated at cancer centers across the United States. By studying these tissue samples and comparing them to tissue samples from people who do not have cancer, researchers will map the genomes of glioblastoma (a malignant brain tumor), lung cancer, and ovarian cancer. Depending on the results of this research, TCGA may map the genomes of other types of cancer.

TCGA recently announced the first results in mapping the glioblastoma genome. Researchers found several mutated genes that are responsible for the development and growth of glioblastoma, including three genetic mutations that researchers previously did not know were common with this type of cancer. This information may help researchers determine that patients with a particular gene that is mutated may benefit from treatments that target that gene, but not from other treatments. Researchers also pinpointed a mutated gene that may cause chemotherapy to not work in some people with glioblastoma.

In addition to TCGA, several other organizations and researchers are mapping individual cancer genomes. Some of the types of cancer under investigation include multiple myeloma (a blood cancer), melanoma (a type of skin cancer), and neuroblastoma (a childhood cancer of the nervous system).

What this means for patients

Although some results of cancer genome mapping may not be ready for use in cancer treatment today, discoveries from this research may lead to better tests to diagnose cancer and find more effective treatments. Talk with your doctor to learn more about the role of genes in cancer, including whether there are tests available to identify mutated genes, and if there are any treatment options that target those genes.

More Information

Genetics

Facts About Personalized Cancer Medicine

Personalized Cancer Medicine: Translating Breakthroughs in Biology into Better Treatment for Patients

Last Updated: July 13, 2009