Carcinogenesis studies with the lyophilized mushroom Agaricus bisporus in mice

Continuous administration of 10, 5, and 2.5% lyophilized Agaricus bisporus (AB) mushroom in the diet of six-week-old, randomly bred Swiss mice for life induced tumors in the lungs, forestomach, glandular stomach, and ovaries in certain groups. Some of the tumor incidences were found to be statistically significant, although no dose-response relationship was established. Histopathologically, the neoplasms were classified as adenomas and adenocarcinomas of lungs, glandular stomach, and ovaries and squamous cell papillomas and carcinomas of the forestomach. AB given in both raw and baked forms induced tumors in the same species in earlier experiments. Since this fungus is consumed in lyophilized form to a certain degree in the United States, the results may carry practical significance.