Dr Rayjean Hung is a senior scientist at Mount Sinai Hospital and faculty at University of Toronto where she specializes in studying populations to identify changes in genetic material that alter cancer risk. She currently holds a Canadian Cancer Society Innovation to Impact Grant, looking at whether identifying genetic changes in DNA found in the blood can be used for early detection of pancreatic cancer. We spoke with her about how her research could help improve survival for pancreatic cancer, and how she became interested in her area of study.
CCS: What is genomics? Why is it important in cancer research?
RH: Genomics is a vast field of science that includes many different disciplines. It focuses on studying the information in the DNA as a whole, rather than focusing on individual parts of the genetic material. Studying genomics is central to understanding many different diseases, including cancer. Tumours develop because of alterations or changes to the genome, such as mutations in specific genes, instability in the genome, or changes to how the genome is read and interpreted by other molecules. Understanding genomics is critical to understanding how cancer develops and progresses.
CCS: What questions are you trying to answer in your research? Why is this important?
RH: In our CCS grant, we are studying pancreatic cancer. We are looking for changes in the genome related to cancer development that can be detected in the blood rather than tumour tissues. This kind of test is often called a “liquid biopsy.”
Pancreatic cancer is a devastating disease. The prognosis after surgery is better, but many people with pancreatic cancer are diagnosed at a late stage when surgery is not an option, so survival is extremely low. If we can detect the genetic changes signalling that cancer is present before there are symptoms, we will be able to detect cancer early, treat it more successfully and improve patients' survival.
CCS: What progress have you made in your research?
RH: In our research, we look for alterations found in the genetic material in the blood in the form of cell-free DNA (cfDNA). This is very challenging to do. cfDNA is found in very low amounts in the blood, and it is very fragmented, so it can be difficult to analyze and find the alterations that signal that cancer is present.
Through our research, we have been able to develop a method, in collaboration with the scientists at the University Health Network, that can analyze the pattern of changes in cfDNA at a genome-wide level, and we found a distinctive pattern of changes that indicate cancer is present. We have been able to demonstrate that this set of changes is also found in the tumour, and it can distinguish people with cancer from people without cancer.
We have run this test for 200 people with cancer and 200 people without cancer, and it was shown to be very predictive of the presence of cancer with high accuracy. Now that we have had some initial success, we are in the process of confirming our results in another group of samples to ensure that the test is as predictive and reliable as it needs to be to be used in a clinical setting.
CCS: How could your research improve detection of pancreatic cancer?
RH: A blood sample is much easier to obtain than a tissue sample. If we can identify specific patterns of changes in a blood sample that indicate pancreatic cancer is present, this test could be offered in the clinic to people who are at high risk for pancreatic cancer, like people with a family history of it, chronic pancreatic inflammation or other risk factors. These people could be monitored very closely so that cancer could be diagnosed at an earlier stage. This test has the potential to be able to detect a tumor when it is still very small and when surgery is still an option.
CCS: How did you become a genomics researcher?
RH: I was always very interested in health-related fields. Specifically, I was interested in studying potential impact at the population level.
Genomics is a multi-disciplinary field, and it is central to understanding many diseases. It’s a very challenging field, but very rewarding. Understanding the genomics of complex diseases helps to provide insights on how they develop, helps to develop screening or surveillance guidelines, identifies potential targets for treatment, and sometimes also helps to point to specific environmental risk factors. By studying genomics, you can address complex research questions from different angles. It can also be applied in different aspects of research from prevention and early detection to treatment. It’s a very exciting field of research.
CCS: What do you like about research?
RH: For me, research is about innovation, and lighting up the black holes in our knowledge. It’s about bridging what we know now with what we can do in the future. In particular, I appreciate that we have the opportunity to improve population health and make a difference through research.