Delivering personalized medicine for cancer patients
Drs. Paul Walfish and Ranju Ralhan, Photo: Erin Howe
By Liam Mitchell, University of Toronto
Not all cancers are the same. Some can develop quickly and are aggressive, while others can develop slowly and be easily managed. Being able to tell the difference is important in determining the care for each patient. But without a crystal ball, what can help doctors determine the best treatment options?
The answer lies in identifying reliable biomarkers, which can be measured to determine how aggressive a particular cancer might be. The result: more personalized medicine for cancer patients.
Genomics, which focuses on a cell’s DNA, has been a popular method for delivering on this promise. Mount Sinai’s Dr. Paul Walfish, and Dr. Ranju Ralhan from the University of Toronto’s the Department of Otolaryngology - Head and Neck Surgery, have focused their research on proteomics, which identifies specific cellular proteins.
“Proteins are really the workhorses of cells,” Ralhan explains. “If you focus your attention on their expression and function, you can quickly obtain an understanding of relevant biomarkers.
Using this approach has led to identification of the S100A7 protein as a predictive biomarker for an oral lesion with dysplasia called a premalignant lesion. These types of lesions can lead to cancer. However, it’s difficult to predict which of these oral lesions will become cancerous and how rapidly. This remains a major clinical challenge and is important for identifying patients who would benefit from early intervention.
“We are extremely pleased to have identified a protein which can predict which oral dysplastic lesions will transform. This will be a great tool to find out which patients really need closer follow-up, and in time this will lead to better patient survival,” says Walfish, who is Director of the Mount Sinai Hospital’s Alex and Simona Shnaider Research Laboratory in Molecular Oncology.
“The overexpression of S100A7 can demonstrate the aggressiveness of the premalignant lesion, which can help doctors determine the best course of treatment,” explains Ralhan, who is the Co-Director of the Shnaider Laboratory and Canadian Institute of Health Research Chair in Advanced Cancer Diagnostics. She notes that treatment for advanced oral cancer can cause severe pain, disfigurement and poor quality of life in survivors. Being able to accurately predict whether treatment may be needed spares the patient unnecessary discomfort by avoiding overtreatment and providing greater cost savings.
Their findings were detailed in October, in the International Journal of Cancer, and have been independently verified by labs in both Toronto and New Delhi. The importance of these findings is underscored by the global rates of oral cancer. Oral cancer is one of the most common cancers in Asia —particularly in India and China — where smoking or chewing tobacco and betel quid are common. Incidents of oral cancer are also increasing in North America.
Working with an interdisciplinary team of researchers that includes pathologists, oncologists and surgeons, Walfish and Ralhan are continuing to explore how protein biomarkers can help diagnosis and prognosis of other epithelial cancers. For example, they have also used their approach to identify biomarkers for types of breast and thyroid cancer.
“Since there is a lot of interest in personalized medicine, biomarkers identified by proteomics offer a more feasible option,” says Walfish.
