A Canadian study showing how cancerous cells are able to survive the body's defense attacks has unlocked one of the greatest puzzles in cancer research, cancer organizations and a study author said Wednesday.

And the finding, published in the latest issue of the US journal Cell, will likely have "profound clinical implications" for treating auto-immune diseases, cancer and transplant rejection, said lead author Chris Bleackley in a phone interview from Calgary, Alberta.

The study, conducted by 12 scientists from the University of Alberta and McMaster University in Ontario, shows how white blood cells which destroy foreign or virus-infected matter carry out their attack.

"White blood cells essentially release little molecular bullets that have to get inside the target cell -- tumor or transplanted cell -- in order to kill it," said Bob Phillips, executive director of the National Cancer Institute of Canada.

"One of the puzzles is how do one of these molecular bullets get inside of cells ... (and) they identified the molecule on the surface of cells that this little bullet uses to get inside," Phillips said in an interview.

Bleackley said the surface receptor binds with the so-called bullets -- a substance known as granzyme-B -- and then they are internalized in the targeted cell, starting its self-destruction.

He compared the action to a letter bomb making its way into a mailbox.

The finding is pertinent to cancer research because other studies have shown that a variety of cancer cells -- including those from breast, liver and pancreatic cancer -- have markedly reduced receptors, preventing the so-called bullets from getting inside the cell and triggering its death.

"If we could somehow work out how to make the tumors to synthesize this receptor cell again, then those tumor cells should become susceptible to the white blood cells," Bleackley predicted.

"That's the next stage (and) that's what we are looking at now," he added.

His team's findings will likely prompt labs around the world and the pharmaceutical industry to re-evaluate possible treatment paths for a wide variety of auto-immune-type health problems.

"If we hadn't discovered this, nobody would have suspected that this was an approach for the treatment of transplants, or to the immune disease or tumors," said the 48-year-old researcher from Manchester, England who came to the university in 1981.

Phillips cautioned, however, that it will take years to determine if the findings "will translate into improved treatments for specific types of cancer."

Bleackley and his team have been working on the puzzle for more than a decade and discovered only five years ago that granzyme-B was transferred, yet still could not figure out how.

"Getting a discovery like this that is so potentially applicable to clinical medicine ... is like winning a gold medal in a world record time," he added.

(From ChinaDaily)