Genomic and Genetic Testing for Cancer

Overview

Researchers have learned a great deal about the thousands of genes in our cells and how changes in some of them are linked to cancer. Testing for these changes can show your risk for some cancers, help with early detection or prevention, and guide treatment.

Genetics and Genomics

Both fields study genes and gene changes, but they look at different things. Genetics studies single genes and how they are passed from one generation to the next. Genomics studies a person's whole set of genes (the genome) and how those genes act with each other and with the environment. Genomics is teaching researchers about gene changes in cancer cells, leading to new treatments aimed at those changes, and it is becoming part of care for many people with cancer.

Genomic Testing

For cancer, genomic testing looks at the genome — or parts of it — inside the cancer cells, to find the gene changes that make them different from normal cells. These changes are usually not inherited; they happen during life and are found only in the cancer. The results can show how fast a cancer may grow and whether treatments such as targeted therapy or immunotherapy are likely to work. The test has many names: genomic profiling, genome sequencing, biomarker testing, tumor testing, tumor genetic testing, tumor marker testing, tumor subtyping, molecular testing or profiling, and next-generation sequencing. It is usually done on tumor tissue from a biopsy or surgery, but sometimes on blood, saliva or other body fluids.

Genetic Testing

Genetic testing looks for changes in a person's own genes that affect cancer risk. It can check one gene or many genes at once (a panel). It can be done before any cancer is found (predictive genetic testing), or after a diagnosis to see whether the cancer came from an inherited change. The results can help estimate the risk of the cancer coming back (recurrence), guide treatment, and tell family members about their own risk. It is usually done on blood or saliva.

Questions to Ask Your Doctor

• Should my tumor have genomic (biomarker) testing, and what could the results change about my treatment?
• Will the test use tumor tissue I already gave, or do I need a new biopsy or a blood test?
• Do I need genetic testing to look for an inherited gene change?
• Will my insurance pay for these tests, and how long do results take?
• Should I meet a genetic counselor before or after testing?

Source: https://www.cancer.org/cancer/understanding-cancer/genes-and-cancer/genomic-genetic-testing.html