The Canadian-born scientist who won the Nobel Prize in medicine Monday for ground-breaking research on the immune system had died on Friday. Nobels are usually not awarded posthumously, and the Nobel committee said they were unaware of Ralph Steinman's death until Rockefeller University told them several hours after the honor was announced. But they said the award still stands, The Associated Press reported. Steinman, 68, died of pancreatic cancer and was being treated with the immunotherapy based on his discovery of dendritic cells two decades ago, according the the university. He is sharing the $1.46 million prize with Bruce Beutler of the Scripps Research Institute in La Jolla and Luxembourg-born Jules Hoffmann based in France.