The leading-edge work of a Memorial researcher is providing new insight into a devastating disease.
Dr. Thomas Belbin, GlaxoSmithKline Chair in Oncology Research, Discipline of Oncology, Faculty of Medicine, is also an associate member of the Beatrice Hunter Cancer Research Institute.
He specializes in the genomes of head and neck cancer cells, which occur in tumours found in various parts of the nose, mouth or throat.
Last year, 7,500 Canadians were diagnosed with some form of this cancer.
Part of his research focuses on the genes and genetic changes that enable cancer to form, grow and spread.
Unique profiles
“My research focuses mainly on finding novel genes that cancer cells like to ‘silence’,” said Dr. Belbin (B.Sc.’90, PhD’99). “They do that not by mutating or deleting the gene, but by suppressing the expression of the gene using the cancer cell’s own regulatory machinery. So, part of my work involves identifying novel genes that fall into this category.”
Dr. Belbin and his team examine several genes that code for KRAB-ZNF proteins, a known cancer suppressor protein.
“Head and neck tumours, as well as other solid tumours, silence these genes with a high frequency, although we don’t really know what they do. There are several projects ongoing in my lab to turn these genes back on, and then observe how their re-expression affects a tumour cell’s behaviour.”
In addition to studying how tumours behave towards cancer-suppressing genes, the group is also gathering insight into what makes these tumours tick.
“We can instead zero in on the most effective treatment straight away.”
Tumours, it turns out, have unique molecular profiles like individual fingerprints.
“These ‘molecular profiles’ of tumours give us a window into sub-types of the disease that we never knew existed,” said Dr. Belbin. “When combined with sophisticated machine learning with computers, you can use this information to try to make predictions about things such as a patient’s outcome, their response to radiation treatment or a particular chemotherapy.”
This approach to treating tumours based on the unique molecular or genetic profile of the patient or tumour is referred to as personalized medicine.
It can take much of the guesswork out of treatment.
“Instead of trying different treatments until we find one that works, we can instead zero in on the most effective treatment straight away, thereby saving time and cost, as well as offering an effective approach to treating the patient.”
‘Virtual goldmine’
Dr. Belbin is passionate about finding better ways to treat head and neck cancer, which can impact essential functions like the ability to swallow and talk.
Surgeries to treat the disease can have psychological effects related to body image or loss of function.
“The more we understand about the disease, the more we can give only the necessary treatment. De-escalating treatment often spares the patient unnecessary surgery or other therapies and is more cost-effective.”
He says there are many reasons to be hopeful. Medical research into head and neck cancer is advancing rapidly.
“Our ability to detect those changes is crucial to catching the disease at a much earlier stage.”
Survival rates for the disease are improving, albeit slowly, and new drugs are coming on the market all the time.
Dr. Belbin says he believes that one of the next big breakthroughs will be at the genetic level.
“The ability to sequence entire genomes in one experiment or measure the expressions of all genes simultaneously is a window into cancers that we never had before.”
He credits the Terry Fox Marathon of Hope Cancer Centres Network’s bank of genomic data as a critical piece of the puzzle.
“When researchers and clinicians across the country come together to build this large repository of data about thousands of patients, and then share that data with researchers, it will be a virtual goldmine of new information for researchers.”
Dr. Belbin adds that new technologies to help detect cancer at the cellular level represent another promising area.
“Cells undergo a variety of molecular changes very early in their transformation to a cancerous cell. So, while cells may look relatively normal in a microscope, many of the changes at the molecular level are already taking place. Our ability to detect those changes is crucial to catching the disease at a much earlier stage, when it can be much more treatable.”
