Cancer care has made great strides over the past decade, and three little letters have made a huge difference in the journey: DNA.
Like detectives working a cold case, scientists are using genes to unravel the mysteries of cancer’s origins and mutations, unearthing clues to a disease of genetic mistakes. The burgeoning field is called genomic medicine, and it is equipping doctors with new tools to target cancer at its source: the blunder coded in its molecular structure.
Just as your genome can be sequenced to identify your unique genetic makeup, decoding cancerous cells can reveal why they’re acting the way they do, and perhaps how to stop their errant behavior. Genomic sequencing is typically reserved for patients with advanced cancers that haven’t responded to traditional treatments like surgery, chemotherapy and radiation therapy, which are effective for most patients. The process of decoding a patient’s genome starts in the lab, where “we are able to use highly sophisticated, highly sensitive equipment to look at tumor abnormalities at a molecular level,” said Dr. Maurie Markman, President of Medicine and Science at Cancer Treatment Centers of America® (CTCA).
Technicians sequence the DNA obtained from a biopsy of the tumor, then scan it for abnormalities. Certain mutations, especially those common to lung, breast and colorectal cancer, have been studied closely over the years, giving oncologists a better understanding of their behaviors—and their response to treatments. If the abnormalities found in the patient’s tumor match known mutations, oncologists can recommend therapies that tend to be effective for that particular malignancy.
“Ideally, it would be great if we had one disease, with one mutation, with one treatment, with one drug, but unfortunately, that’s not the case,” said Dr. Shayma Kazmi, Medical Oncologist and Hematologist at CTCA. “For people who have one of the identifiable mutations, if we can target that with treatments that have been known to work elsewhere, perhaps we can have better outcomes.”
The discoveries are helping to refine the approach to cancer treatment. Oncologists, for example, have found similarities in the genetic makeup of different types of cancer. One patient’s lung tumor, say, may look and act much like an abnormality more typical in breast cancer. This revelation can open up new possibilities for drug therapies that may not have otherwise been considered in that patient’s treatment plan.
The targeting process is so precise that the field has earned a new name:precision medicine. And cancer specialists like Kazmi predict it will lead to a day when cancer is no longer defined by where it’s located—pancreatic cancer in the pancreas, liver cancer in the liver—but by the molecular structure coded in its DNA.
The expanding landscape is bringing new prospects, and new opportunities. As knowledge of genomic medicine has increased, its cost has plummeted. Sequencing a human genome today costs less than $10,000, compared to more than $100 million in 2001. Not only are the tests more available to patients, but more oncologists are trying their hand at tumor testing and building on the base of knowledge.
“As much as it is a really promising future, it’s a really exciting to be part of the changing landscape,” Dr. Kazmi said of genomic profiling for cancer patients.
And yet, there are still many unknowns. For example, one tumor may spawn several varying mutations, and they all may interact differently depending on the patient. Scientists don’t yet know why that is, or for that matter, why some abnormalities lead to cancer and others don’t.
But the prospects for discovery are bright. Those who dedicate their lives to understanding cancer say there is no overestimating the potential for genomic medicine to dramatically improve the diagnosis, treatment—and prevention—of cancer.
“This is an incredibly powerful, positive force in medical care,” Dr. Markman said. “It is the tsunami on our shores, and it’s going to take over all of medicine.”