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GEORGETOWN, ON - MAY 7: A surgical scar is barely visible as a part in the middle of Rilley's skull. In November 2010 Rilley the 12 year old beagle mix dog belonging to the Janke family underwent brain surgery in Minnesota to remove a tumor in his brain lining. He is now cancer free. The clinical trial involved re-introducing Rilley to a vaccine made from the cancerous cells removed from the brain. Researchers have gone on to do trials with humans. (Chris So/Toronto Star via Getty Images)

GEORGETOWN, ON - MAY 7:  A surgical scar is barely visible as a part in the middle of Rilley's skull. In November 2010 Rilley the 12 year old beagle mix dog belonging to the Janke family underwent brain surgery in Minnesota to remove a tumor in his brain lining. He is now cancer free. The clinical trial involved re-introducing Rilley to a vaccine made from the cancerous cells removed from the brain. Researchers have gone on to do trials with humans.        (Chris So/Toronto Star via Getty Images)