Over the past decade, tongue cancer has increased two to four-fold in young people under 45. This alarming trend is occurring independent of factors normally linked with this disease, such as smoking, alcohol consumption or HPV. Research to date has not determined the cause of this worrying trend.
Tongue cancer is a debilitating disease and the available treatment options are limited and drastic. Because treatment usually requires radical surgery and high dose radiation therapy, people with tongue cancer may suffer permanent disabilities in speech and swallowing, facial disfigurement and lifelong dependence on feeding tubes for nutrition.
60% of cases of tongue cancer recur within five years of treatment, either in the mouth or other parts of the body. There are no effective second-line treatment options, and if the cancer returns to a distant site of the body, the chance of survival is low.
Our researchers are determined to advance our understanding of the cause of this cancer. Existing research to date has looked into the coding regions of DNA. This is the part of our DNA that maps out the proteins that make us who we are. It makes up 2-3% of the human genome, or our complete set of DNA.
The rest of our DNA is non-coding DNA, often called ‘dark matter’ or ‘junk’ DNA.
Our researchers believe that the driver of tongue cancer in young people lies in this junk DNA. Although junk DNA makes up the majority of the human genome, it has never before been investigated as a cause of tongue cancer.
Earlier this year, thanks to the support of our donor community, we welcomed a new research fellow to the head and neck team – Dr Dario Strbenac. A bioinformatician with the School of Mathematics and Statistics at The University of Sydney, Dario is passionate about mathematics, in particular looking at patterns in big data.
Dario is analysing the whole genome of tongue cancer patients in the study and creating computational models.
“For each patient,” Dario explains, “we’re looking to find what has changed in their cancer sample compared to the normal sample. It could be that their DNA sequence has changed, or they might have more copies of their DNA than they should have. It might be that a chromosome has broken apart and has stuck to other chromosomes. We are looking for these kinds of patterns of changes and whether they occur across the entire patient sample, meaning there are chromosomal commonalities among the patients.”
“So far, we’ve completed sequencing and analysis of two samples from the same patient, healthy tissue and tumour tissue. What we’ve found is that at some stage in the past, this person has had their whole genome duplicated. We are all meant to have two copies of every chromosome, but this person has four copies, so a bit too much of everything.”
It’s early days for the research, but it has already produced some interesting results— the team has discovered a genome duplication in 30% of samples tested.
This interesting finding brings us much closer to understanding the causes of tongue cancer in young people where there is an absence of known risk factors.
Once we understand the mechanisms that drive tongue cancer, we can work towards developing a diagnostic test for early detection and preventative strategies to reduce the incidence of the disease, which will ultimately save lives.