Genomic Testing

Discovering individual cancer genes with mutations

Genomic testing—sometimes known as DNA sequencing, whole or partial genome sequencing—is the process of discovering individual cancer genes with mutations.

The IU Health Precision Genomics program is one of only a few in the United States to provide comprehensive genomic testing, which may include testing the whole genome DNA of 3 billion base pairs, 20,000 genes.

We’ve learned that an individual’s genetic makeup can significantly impact the effectiveness of drugs and any adverse side effects that someone might have to those drugs. We use the insights from these tests to avoid drugs that might be less effective at treating your cancer or could cause significant side effects for you.

Genetic Testing vs. Genomic Testing

Genetic and genomic testing can tell us a great deal about someone’s likelihood of getting cancer or which treatment options may be most effective. But there’s often confusion about these two types of tests.

Both genetics and genomics are concerned with the DNA that defines us. Our genome is composed of a series of three billion letters that forms a blueprint telling every cell in our body what to do. Genomics is a newer term that describes a wider look at the overall code. Essentially, think of them as the forest or the trees.

Genetics (Often Referred to as Inherited Genetics of Germ-Line Genetics)

Classic genetics refer to what we inherit from mom and dad; our DNA blueprint is a mixture of letters from both of our parents. While the DNA from one person to another is about 99.9 percent identical, about 0.1 percent of it is different from person to person. Interestingly, it’s that 0.1 percent difference that makes each of us unique – it gives some people blue eyes and others brown; makes some people grow tall and others short. It’s that same 0.1 percent that can also increase our risk for cancer.

Studying inherited genetics helps us:

  • determine whether or not we’re predisposed to a higher risk to cancer
  • how early we should start screening
  • what kind of tests we should do
  • determine whether patients may want to take medications to decrease the likelihood of getting cancer or opt for surgeries

This is an aspect of genetics that has become very powerful in terms of informing patients about their risks of cancer.

What to Expect

We’ve learned that an individual’s genetic makeup can significantly impact the effectiveness of drugs and any adverse side effects that someone might have to those drugs. We use the insights from these tests to avoid drugs that might be less effective at treating your cancer or could cause significant side effects for you.

Genetic Testing vs. Genomic Testing

Genetic and genomic testing can tell us a great deal about someone’s likelihood of getting cancer or which treatment options may be most effective. But there’s often confusion about these two types of tests.

Both genetics and genomics are concerned with the DNA that defines us. Our genome is composed of a series of three billion letters that forms a blueprint telling every cell in our body what to do. Genomics is a newer term that describes a wider look at the overall code. Essentially, think of them as the forest or the trees.

Genetics (Often Referred to as Inherited Genetics of Germ-Line Genetics)

Classic genetics refer to what we inherit from mom and dad; our DNA blueprint is a mixture of letters from both of our parents. While the DNA from one person to another is about 99.9 percent identical, about 0.1 percent of it is different from person to person. Interestingly, it’s that 0.1 percent difference that makes each of us unique – it gives some people blue eyes and others brown; makes some people grow tall and others short. It’s that same 0.1 percent that can also increase our risk for cancer.

Studying inherited genetics helps us:

  • determine whether or not we’re predisposed to a higher risk to cancer
  • how early we should start screening
  • what kind of tests we should do
  • determine whether patients may want to take medications to decrease the likelihood of getting cancer or opt for surgeries

This is an aspect of genetics that has become very powerful in terms of informing patients about their risks of cancer.

Genomics

In the newer world of genetic technology, there’s an ability to step back and read the wider genomics to detect abnormalities, which we can think of as typographical errors in those DNA letters.

When we examine a patient’s tumor, we can identify typos and, if the spellchecker that we’re born with doesn’t fix those typos and if they occur in the wrong place, that cell can no longer follow the instructions in its blueprint. This cell no longer respects boundaries or dies when it’s programmed to die. This is essentially cancer: a disease of typographical errors in our DNA blueprint.

This is important because we now have the ability to look across all three billion letters in our genomic code to locate those typographical errors. Genomic testing allows us to:

  • locate the typo that resulted in the gas pedal being stuck “on,” giving us unprecedented ability to try to match that faulty gas pedal with a specific drug known to release that pedal
  • more precisely identify what’s gone wrong in the tumor
  • provide clues as to which drugs may be the most efficient way to kill that tumor

Genomic testing on tumors is often used with patients who have advanced cancer, in the hope that it provides some insight as to best drugs to use or best clinical trials to enter. But the use of either test continues to evolve as science advances.

Precision Genomics 2018 04

Genomic testing is offered through a doctor's referral only. Talk with your doctor to see if this testing may be right for you.

Patient Stories for Genomic Testing