“For many people with cancer, the most difficult news they may receive is that their cancer has spread, or metastasized,” says Dr. Carol Swallow, a surgical oncologist and associate scientist at Mount Sinai Hospital who specializes in colorectal cancer. She explains that when a primary colorectal tumour spreads, typically to the liver or lung, patient survival rates drop significantly.
Metastasis is a complex process whereby cancer cells disengage from the original tumour, enter the bloodstream, and infiltrate healthy tissue in a new part of the body, in conditions ‘hostile’ to the tumour cell’s makeup.
But Dr. Swallow anticipates that, through Mount Sinai’s Sydney C. Cooper Program for the Prevention of Cancer—an innovative program begun in 2008 that links basic health research with clinical research to solve a particular medical problem like metastasis— and her work with scientist Dr. Jim Dennis, significant new progress will be made to decrease the rates of metastatic cancer among patients at Mount Sinai.
Dr. Dennis, a Senior Investigator at the hospital’s Samuel Lunenfeld Research Institute, has been studying metastasis for decades. One of his current projects focuses on cancer cell metabolism, and how cancer cells consume more energy, grow aberrantly, and spread throughout the body.
Dr. Dennis’ lab also isolated a gene called Plk4, which is implicated in liver cancer and promotes genome instability—a precursor to cancer progression and metastasis. His team is using mouse models to study the effects of Plk4 mutations and the resulting changes in cell metabolism and thus propensity for cancerous growth.
But while the basic research in Dr. Dennis’ lab is critical to understanding metastasis, it is incomplete without clues from patient samples and clinical data.
That’s where Dr. Swallow’s clinical work and her access to the Familial Gastrointestinal Cancer Registry—a vast database of patient tumour samples from people with inherited colorectal cancers—comes into play.
“We’re able to identify and analyze genes from a patient’s primary tumour, and compare them to those from metastatic tissue,” says Dr. Swallow. “Few other centres in North America have access to such a rich source of research data. What we ascertain from the samples will help us give patients more individualized treatments, customized to their specific tumour type.”
Dr. Swallow points to successes made to date through this model of research, and says that her team has already identified a number of patients for whom they have clinical data and tumour samples from the primary lesion and from the metastases that emerged years later. “With this information, I can work with Dr. Dennis and others at the Lunenfeld to sequence and analyze gene expression, finding clues that will help us understand how and why some of the initial cancer cells spread.”
“Collaborating with Dr. Swallow really helps us focus on the problems of metastasis in human cancers, especially in relation to Plk4,” says Dr. Dennis. “In working with cancer patients daily, she sees our scientific questions through that clinical lens. And this gives our team-based approach greater ability to stop patients’ cancers from spreading.”
“The interaction among clinicians and researchers here at Mount Sinai is among the most collegial I’ve encountered,” says Dr. Swallow, who joined the hospital in 1996 from Memorial Sloan Kettering Cancer Center. “There is a genuine appreciation that clinicians can offer conceptual and analytical efforts to complement the fantastic basic research being explored at the Lunenfeld.”