Tumor induction by 4-(methyl)benzenediazonium sulfate in mice

4-(Methyl)benzenediazonium sulfate (MBD) was administered to Swiss mice by subcutaneous injection at weekly intervals 19 or 16 times at 50 μg/g body weight. The treatment gave rise to tumors of the subcutaneous tissue and skin. The tumor incidences in the groups with 19 injections were 12 and 6% in females and 12 and 4% in males, respectively, while in the group with 16 injections were 24 and 14% in females and 50 and 4% in males, respectively. The corresponding tumor incidences in the untreated controls were 2 and 2% in females and 8 and 2% in males, respectively. Histopathologically, the tumors were classified as fibromas, fibrosarcomas, myxosarcomas, fibromyxosarcomas, rhabdomyosarcomas and angiosarcomas in subcutis and squamous cell papillomas and carcinomas of skin. MBD is closely related to 4-(hydroxymethyl)benzenediazonium ion (HMBD), an ingredient of the cultivated mushroom Agaricus bisporus. The conversion of HMBD to MBD appears to be a distinct possibility.