Johannes Andreas Grib Fibiger (23 April 1867 – 30 January 1928) was a Danish scientist, physician, and professor of pathological anatomy who won the 1926 Nobel Prize in Physiology or Medicine. Fibiger had claimed to find an organism he called Spiroptera carcinoma that caused cancer in mice and rats. He received a Nobel prize for this discovery. Later, it was shown that this specific organism was not the primary cause of the tumors. Moreover, Katsusaburo Yamagiwa, only two years later in 1915 successfully induced squamous cell carcinoma by painting crude coal tar on the inner surface of rabbits' ears. Yamagiwa's work has become the primary basis for this line of research. Because of this, some consider Fibiger's Nobel Prize to be undeserved particularly because Yamagiwa did not receive the prize. Encyclopædia Britannica s guide to Nobel Prizes in cancer research mentions Yamagiwa's work as a milestone without mentioning Fibiger.