Ivan Koloff, 74, one of pro wrestling's leading heels of the 70s and 80s, is battling liver cancer.

Koloff is best known for his January 18th, 1971, win over Bruno Sammartino in Madison Square Garden which ended up being Sammartino's only pinfall loss in that building in his entire career. The win ended Sammartino's nearly eight year run as WWWF champion.

Koloff had already established himself as a major star years earlier by dropping his Irish gimmick as Red McNulty, and becoming the Russian Bear in Montreal, where he headlined a number of big drawing shows against Jacques Rougeau Sr. and others.

He was a top heel everywhere for more than 20 years, headlining at one point or another in almost every major territory and all over the world. In the early 70s, he and The Sheik were the two top heels in the U.S., and he remains to this day the only heel ever to leave the WWWF because he was so over they were afraid to keep him there for fear of a bad incident, because of the emotion caused by his win over Sammartino.

He left the WWWF only a few weeks after the win, dropping the title three weeks later to Pedro Morales, and not even having one rematch in Madison Square Garden, nor did he feud with Sammartino outside of Pittsburgh, which was a different territory at the time run by Sammartino and not Vince McMahon Sr.

He had a run on top during the second hottest period in AWA history, where he was a longtime top contender for Verne Gagne and wrestled him in the main event of a 1972 show at Soldier Field in Chicago.

Just as cable television was taking off, the tag team of Ole Anderson & Ivan Koloff were the headliners in Georgia, with a long program against Dusty Rhodes and a revolving set of partners.

He settled in the Carolinas in the 80s, forming a strong tag team with Don Kernodle, and more famously, the Russian trio with his so-called nephew, Nikita Koloff, and Krusher Khrushev, who later became Demolition Smash, Barry Darsow.

Koloff's career on a major league level ended in 1989 after Crockett Promotions was purchased by Turner Broadcasting. He had a babyface turn, that worked for a short period of time but was clearly not going to suit him in the long run. He worked regularly for years doing independent shows and was voted into the Hall of Fame in 2015.

Koloff was known in his heyday for his conditioning in the ring and being a top level worker. While the Sammartino win was big, the reality is he got over everywhere he went at the top level, in places where the fan base didn't even know Sammartino, but it did make him a larger-than-life heel when he would return to the WWWF going after titles, and was one of the best drawing challengers that would be brought in during the 70s and early 80s.