"Non-small cell lung cancer remains the leading cause of cancer deaths worldwide," explains Dr. Tsao. "While there are several anti-cancer agents aimed at genetic mutations, most of the tumours do not harbour these targetable mutations and new effective anti-cancer agents are still much needed."
Using tumour samples from patients at the time of diagnosis and when cancer had returned, the research team implanted and successfully grew 137 tumours in laboratory models known as patient-derived xenografts. These models were established using two of the most common and aggressive types of lung cancer: adenocarcinoma and squamous cell cancer.
The research team then extensively studied the genetics and proteins present and used this information to construct molecular profiles of the tumours. Through analyzing the profiles, they found that the laboratory models closely mirrored human disease. The researchers also confirmed that the models had genetic mutations that are known to promote cancer cell growth, such as those in the KRAS and EGFR genes.
Going further, the team looked at modifications to genes known as epigenetic changes that govern whether genes were turned on or off. These analyses also confirmed that laboratory models matched up with what is observed in human cancer.
"We did this to see if the set of proteins in these cancer models could provide new insight into human disease."
By comprehensively examining the proteins in the laboratory models, the research team discovered three adenocarcinoma and two squamous cell carcinoma proteotypes that were each associated with different patient outcomes.
"Our findings show that laboratory models not only closely reflect non-small cell lung cancer in patients, but they can also be used to provide new insight into treatment outcomes," Dr. Tsao said in summarizing the findings.
"Laboratory models can help us look more closely at the bigger picture – to consider genetics as well as the protein landscape – so that we can identify anti-cancer therapies that move beyond targeting single mutations," said Dr. Tsao, who is also at U of T the M. Qasim Choksi Chair in Lung Cancer Translational Research, and a professor in the departments of Medical Biophysics, and Laboratory Medicine and Pathobiology.
This work was supported by the province of Ontario, the Canadian Cancer Society, the Canadian Institutes of Health Research, the Hospital for Sick Children (SickKids), the National Sciences and Engineering Research Council of Canada, the Terry Fox Foundation and The Princess Margaret Cancer Foundation. UHN News