Precision Medicine

Precision medicine is a new way to fight cancer. Scientists use a person’s unique genetic makeup to develop an individualized treatment plan to target cancer cells.

Your jaw drops when you look at the tiny lump of tissue sitting in a small tray in the lab at Wake Forest Baptist Medical Center.

“This is where it starts,” explains Kathy Saylor, assistant manager of the histology lab in the Department of Pathology. “This is brain tissue. It’s been cut by residents in the operating room pathology lab and sent to us.”

Brain tissue. It is eggshell colored and looks a bit like a lump of fish. But the more you examine it, the better you can make out the tiny folds that you always see in pictures of the brain. You wonder what memories and functions were lost when the piece was removed. You wonder how the patient is doing, because the patient is fighting cancer.

“We treat everyone of these patients like it was our own family — mom, dad, brother, sister,” says Saylor. “We know what patients go through because some of us have been on this end so we know what it’s like. So this isn’t just a job. We try to do the best job we can and give the pathologist something to read so they can give the patient good news or bad news."

The tissues are sliced in segments that are four microns wide. Then, they are placed on a slide and stained, which highlights various parts of the tissue. The sample is sent to a doctor for examination to determine if cancer is present. In many cases there are multiple samples from the same patient because samples must be taken every few centimeters around a tumor to determine how far the cancer may have spread.

It is life-changing, and often life-saving, information that is determined from a tiny tissue sample. But the newest front in the battle against cancer starts even smaller.

“If you take a tiny drop of blood and put it in this tray, you can sequence the person’s entire genetic structure using this machine,” says Pam Smitherman, a research technician in Wake Forest Baptist Medical Center's Comprehensive Cancer Center. “If you wanted to sequence only one gene to check for a certain disease, you would program the machine to do just that.”

You read that correctly. The fight against cancer is turning to the genetic level with the sequencing of DNA, or deoxyribonucleic acid. The molecule found in the nucleus of a cell — which contains the entire set of instructions for an organism to develop, survive and reproduce — is part of a groundbreaking effort to fight cancer.

DNA sequencing is a process that used to take weeks or months. Now it can be done in a few hours.

Doctors believe if you can find the DNA sequence of the cancerous tissue, you can find a medicine that will attack the specific type of cancer, not only preventing it from spreading but ultimately destroying it.

“What we would do is sequence the normal genome of an individual, which we would get from a white blood cell, or if we want to fight the cancer in an organ, we would get normal tissue from the organ,” says Dr. Gregory Hawkins, an associate professor at Wake Forest Baptist Medical Center's Center for Genomics and Personalized Medicine. “That gives us a baseline to start. Then we get the DNA from the tumor tissue. After sequencing the healthy and the tumor tissue, we then go back and look for the difference.”

The program is called precision medicine.

“By dissecting the genetic makeup of the healthy organ and the cancerous tumor, we can identify what really confers this tumor its growth advantage and what makes it resilient to other drugs,” says Dr. Boris Pasche, director of the Comprehensive Cancer Center. “This analysis provides our first segue way into finding drugs for specific tumor types that are more likely to be effective and less damaging to the patient because they will be targeting the Achilles heel of the tumor.”

Doctors are looking at the molecular level for cancer treatment because ultimately, at its most basic level, cancer is caused when there is an error in copying the genetic sequence in the DNA. 

Doctors say precision medicine offers new treatment options for patients who have few options, including patients who have been treated for cancer but the disease has returned or suffer from a rare form of cancer.

The hope for precision medicine is centered in the belief that knowing what mutations are present in a cell can provide clues as to which ones are driving its growth. 

“The ability to tailor a patient’s therapy to the mutational components of their cancer and not the way we’ve done for years is really a paradigm shift in oncology,” says an excited Dr. Timothy Pardee, director of leukemia translational research at Wake Forest Baptist Medical Center. “In the past, we would tell a patient with liver cancer that they would get chemotherapy x because that was what the traditional treatment called for. But to be able to say 'you have liver cancer but you have a mutation in gene y so we’ll give you a different treatment' is a tremendous difference and offers an entirely new range of treatment. I think it is in its early days but it is very exciting.”

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