Role of talc and benzo(a)pyrene in respiratory tumor formation. An experimental study

Biologic and morphologic alterations caused by repeated intratracheal instillations of talc, alone or in combination with benzo(a)pyrene (B(a)P), were studied in Syrian golden hamsters to determine the possible carcinogenic and cocarcinogenic effects of talc. Talc alone failed to induce respiratory tumors, granulomas or mesothelial proliferation, but when a mixture of equal quantities of talc with B(a)P was administered, papillomas, squamous cells carcinomas and undifferentiated tumors of the larynx, trachea and lungs resulted. It therefore appears that in the hamster, talc is devoid of carcinogenic activity in itself, but does affect the activity of polycyclic hydrocarbons.