Cancer induction in mice by feeding of the uncooked cultivated mushroom of commerce Agaricus bisporus.

The cultivated mushroom of commerce in the Western hemisphere, Agaricus bisporus, was given p.o. to randomly bred Swiss mice for 3 days and was followed by semisynthetic diet for 4 days each week for life. The mice were 6 weeks old at the beginning of the experiment. As a result of treatment, tumors were induced in the bone, forestomach, liver, and lungs in the following incidences: 16, 38, 8, and 40% in females and 16, 28, 12, and 62% in males, respectively. The corresponding tumor incidences in the untreated controls were 0, 0, 0, and 26% in females and 0, 4, 2, and 34% in males, respectively. Histopathologically, the tumors were classified as osteomas and osteosarcomas, squamous cell papillomas and carcinomas of forestomach, benign hepatomas, and adenomas and adenocarcinomas of lungs. The investigation thus proves the carcinogenicity of uncooked Agaricus bisporus.