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Last year the Canadian Cancer Society reported that breast cancer was the leading cancer diagnosis for women and the second most prevalent type of cancer diagnosis across the country. While new cases were still in the tens of thousands, the report indicated some positive progress with new diagnoses trending downward and the survival rate of breast cancer significantly increasing over the past few decades. A critical factor in continuing this momentum to beat cancer is early detection and treatment.

A team of researchers at Queen’s University, led by Dr. Christopher Mueller (Queen’s Cancer Research Institute), have developed a new detection and characterization method based on the presence of circulating tumour DNA in the blood called mDETECT (methylation DETEction of Circulating Tumour DNA). Using a liquid biopsy (a blood test), the team has developed a method that is a more sensitive means of detecting and monitoring the presence of cancer. This innovation was recently published in  based on their study examining women with metastatic breast cancer, specifically Triple Negative Breast Cancer (TNBC) who are undergoing active therapy for their disease.

"TNBC makes up about 20 per cent of all breast cancers and it is often more aggressive than other types of breast cancer, and it is the type of cancer that women who are carriers of the BRCA1 mutation tend to develop, so that is why we decided to start with this type of cancer," says Dr. Mueller. "What is great about this study is that we had a lot of collaboration both locally and with the Curie Institute in France."

The project began while Dr. Mueller was on sabbatical in 2014 and 2016 at the Curie Institute in France with its Circulating Biomarkers group. Following funding from the Canadian Cancer Society Research Institute, Dr. Mueller was able to begin development of the mDETECT test at Queen’s while using patient blood samples from the Curie Institute. Many of these samples had been previously analyzed by other tests, providing a database for Dr. Mueller and his team to compare the performance of mDETECT to previous mutation-based assays. Kingston was also the location of his control group for the study. Funding from Breast Cancer Action Kingston allowed for the recruitment of 100 local women, who did not have cancer, to donate their blood and help determine the validity and usefulness of the test.

"As advocates for a group of breast cancer patients and survivors, Breast Cancer Action Kingston (BCAK) is proud to have been an essential part of this research," says Lynne Funnell, President of BCAK. "We welcome any and all research that leads to the early detection and subsequent early treatment of breast cancer."

The mDETECT test allows for real time monitoring of a patient’s response to chemotherapy to optimize the treatment. It also supports the early detection of relapse as the success of therapy is much higher if the disease is caught earlier. For patients with TNBC, which is often resistant to specific chemotherapeutic agents, this test can determine if the treatment is working much faster and more sensitively than conventional methods ensuring the best treatment is being given.

"If the signal in women without cancer is low enough, this test could be used for earlier detection of cancer, potentially replacing screening mammography," says Dr. Mueller.

The impact of this innovation could be game-changing in cancer diagnostics. Dr. Mueller and his team have already developed eight mDETECT tests for different cancers, including uveal melanoma, prostate, pancreatic, and lung, the most prevalent cancer diagnosis in 2020. His students are also helping to advance the research, with fourth-year undergraduate and graduate students using the mDETECT development in their own research projects. Dr. Mueller hopes to expand his research to the list of frequent and lethal cancers and to include all types of breast cancer, as well as make the test even more sensitive allowing for earlier detection.

Through Queen’s Partnerships and Innovation (QPI), Dr. Mueller is working to license this healthcare innovation so it can be put into practice, with its added benefit as an economical alternative to current methods. There are several large corporate players in this field, with the largest company, , attracting over $2 billion in funding.

For more information, read Dr. Mueller’s article "A DNA Methylation Based Liquid Biopsy for Triple Negative Breast Cancer" in and his contribution to from the Nature Portfolio Cancer Community.