History of Personalized Medicine Brings Future Hope to Lung Cancer Patients
After feeling a tickle in his throat for about a month, Victor visited the University of Chicago Medicine campus in June 2010 for a check-up. It had only been a very quick tickle, which caused him to clear his throat a half dozen or so times a day, but he wanted to make sure his health remained stable.
“That’s how it all started,” said Victor, a plastic surgeon in the suburbs of Chicago. Medical center physicians took X-rays and diagnosed him with non-small cell lung cancer, one of two main types of lung cancer. His cancer too advanced for radiation, Victor underwent two courses of chemotherapy.
But Victor wasn’t sure how he got to that point. Having only smoked very briefly for a few months during college 40 years ago, he could not say what caused his cancer.
“That’s one of the biggest challenges for us in the future--what can cause lung cancer, especially when there seems to be no toxin exposure,” said Ravi Salgia, MD, PhD, director of the Chest Oncology Program and the Thoracic Oncology Research Program at the medical center.
Yet, an increasing number of genetic tests are enabling doctors at the University of Chicago Medicine to see far beyond patients’ physical symptoms and into the root cause of their diseases. Such vision already has resulted in promising, personalized treatments.
In Victor’s case, Salgia could not initially single out a direct cause for his disease--that is, until he ran a test, which showed that a specific genetic mutation was driving Victor’s cancer. This mutation involved the anaplastic lymphoma kinase (ALK) gene.
Part of the ALK gene was breaking off of its chromosome and reattaching itself to a neighboring gene on the same chromosome.
Scientists discovered this new fusion gene, EML4-ALK, in 2007. Researchers at the drug company Pfizer have since been developing a drug to block signals from the fusion gene. Though less than 5 percent of lung cancer patients have this specific mutation, lung cancer affects millions of people. That means thousands of people could potentially benefit from an ALK-inhibiting drug.
“It’s fortuitous that this was just identified recently, and (Victor) did turn out to be positive for it. It was the right thing at the right time,” Salgia said.
He started Victor on two pills daily, in a Phase I trial of the drug Crizotinib. It was at the medical center within the past year that physicians helped champion Crizotinib, pushing for individualized genetic testing and patient trials.
A History of Mutations
Victor's mutation is called an ALK translocation, a type of genetic alteration with which the University of Chicago Medicine has a long history. Translocations were first discovered at the University of Chicago nearly 40 years ago, completely revolutionizing the way scientists think about, research, and treat cancer.
The woman behind the discovery of translocations is Janet Rowley, MD, Blum Riese Distinguished Service Professor of Medicine, Molecular Genetics & Cell Biology and Human Genetics. She observed the first translocation--a switch of part of chromosome 8 with part of chromosome 21--at her dining room table.
Today, with increased genetic testing and personalized medicine, such discoveries have led to drug treatments very specific to different types of cancer.
Rowley, in 1972, didn't dare think about what this could ultimately mean for science. "It wasn't clear what the translocations were doing. Because it was so new and the consequences were so unknown I didn't speculate," she said.
Since then, researchers around the world have discovered dozens of other translocations, implicated in leukemia, lymphoma, prostate, breast, and lung cancers. One of those translocations--involving chromosomes 9 and 22, which Rowley also discovered--led to a drug called imatinib.
Physicians use imatinib to treat chronic myelogenous leukemia--with a success rate higher than 90 percent. Rowley called people's responses to it "remarkable and very heartening." She receives letters from patients and their families about how imatinib has made their diseases manageable, instead of fatal.
Future of Personalized Medicine
Victor, the hundreds of other patients on the trial for Crizotinib, and Salgia hope to tell the same success story.
“Victor is a great person, and he is responding incredibly well,” Salgia said. “He is very cognizant of his disease, as well as his new therapy.”
Victor’s last CAT scan showed his tumor had shrunk and was not producing any new growth spots. Salgia views this as a good thing for Victor, as well as for the future of personalized, genetically based medicine. “Every patient is different, and we need to individualize every patient’s therapy,” he said.