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Cancer Should Be Reclassified By Molecular Signature Rather Than Tissue Type, Study Suggests

A tumor that arises in the prostate may well have the same molecular signature as one that occurs in the breast. Annie Cavanagh/Wellcome Collection

We tend to group cancers together depending on where in the body it originated, be it the breast, stomach, or prostate. But a new report is arguing that this could be detrimental to the treatment of patients and that cancers should be reclassified depending on their molecular signature instead.

The work, carried out by the US-based National Cancer Institute and National Human Genome Research Institute, form the last part of The Cancer Genome Atlas. It looked at tumor samples taken from 10,000 patients and categorized each one, finding that they represented 33 different cancer types that could be reclassified into 28 molecular types or clusters.  From this, the team has published 27 papers.


Interestingly, out of these clusters of cancers, nearly two-thirds were heterogeneous, in that they contained tumors derived from multiple different tissue types that ordinarily would be treated entirely differently. One tumor type was found to arise in a massive 25 different parts of the body.

“Insights about how one type of cancer relates to another form of the disease can have real clinical implications,” explained University of California Santa Cruz’s Josh Stuart, an organizer of the Pan-Cancer Initiative of which is research is part of, in a statement.

“In some cases, we can borrow clinical practices from better-known diseases and apply them to cancers for which treatment options are less well defined.”

This is really fascinating because it means that if they find one type of cancer in the bowel has a similar molecular signature to another found in the lungs, for example, then the drugs normally reserved to treat the former may well work on the latter.


The work so far is basically a roadmap from which other work can then be based. “It’s a survey of what kinds of overarching systems underlie the data," said Stuart. "It’s less about clinical implications, and more about the patterns we’ve found.” 

These results are yet to have any application in the real world, but future clinical trials could help answer whether this new way of looking at, and therefore treating, cancer has any merit. The results could be that a new perspective on how to classify cancers could potentially help save lives.  

“It’s time to re-write the textbooks on cancer,” said co-author Christopher Benz.


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