Four-time Iditarod champion Susan Butcher died Saturday of complications from a recent bone marrow transplant. Her health concerns began three years ago when she was diagnosed with polycythemia vera -- a rare disease that causes bone marrow to produce excess blood. Then last winter, she was diagnosed with leukemia. Her subsequent bone marrow transplant on May 16 cleared her system of cancer. But she developed graft-versus-host disease -- where transplanted cells start attacking the digestive system. A fever, a change in her potassium level, and a trip to intensive care prompted her husband to write on his blog Friday of her condition. He reported that if she remained stable, she would return to her previous hospital room and would work on recovering. But sadly, Butcher did not recover.

Butcher dominated the 1,100-mile sled-dog race from Anchorage to Nome in the late 1980s and brought national attention to the grueling competition. She won the 1986 race and became the second female champion -- and then won again in 1987, 1988, and 1990. She finished in the top four through 1993. Butcher also made headlines in 1979 when she helped drive the first sled-dog team to the 20,320-foot summit of Mount McKinley -- the highest peak in North America.

Butcher, who ran her last Iditarod in 1994, grew up in Cambridge, Massachusetts and was married with two daughters -- ages 10 and five. Butcher was 51 years old.