The former World Heavyweight Champion, nicknamed Smokin' Joe, learned he was battling the deadly disease around four or five weeks ago and the 67 year old has been receiving treatment at a hospice in Philadelphia, Pennsylvania for the past week (begs31Oct11).
Confirming the news to the Associated Press, Frazier's manager Leslie Wolff says, ""We have medical experts looking into all the options that are out there. There are very few. But that doesn't mean we're going to stop looking.
""We appreciate every prayer we can get. I've got everybody praying for him. We'll just keep our fingers crossed and hope for a miracle.""
Frazier became the first man to beat Muhammad Ali when he knocked him down in the 1971 fight regularly referred to as the Fight of the Century.
But he struggled in repeated performances against Ali and lost two other bouts against him, including the epic Thrilla in Manila fight in 1975.
He earned the heavyweight title in 1970 and successfully defeated it four times, before losing the championship belt to George Foreman in 1973.