Large interindividual variations in metabolism of benzo(alpha)pyrene by peripheral lung tissue from lung cancer patients.

A very large variation (44-fold) was observed in the ability of short-term organ cultures of peripheral lung tissue from lung-cancer patients to metabolize the environmental carcinogen benzo(alpha)pyrene to organic solvent-soluble metabolites. The amounts of benzo(alpha)pyrene (2 microM) metabolized ranged from little (1%) to almost total (96.2%) metabolism within 24 h of culture. Previous work by Kellerman et al. (1973) has suggested a relationship between susceptibility to lung cancer and the indicibility of aryl hydrocarbon hydroxylase activity in cultured human lymphocytes. The metabolic fate of carcinogenic polycyclic aromatic hydrocarbons in the respiratory tract in vivo is undoubtedly more closely mimicked by short-term organ culture of human lung than by cultured lymphocytes. Thus the very wide interindividual variation observed in pulmonary metabolism of benzo(alpha)pyrene in this study and the large variations in covalent binding to human bronchial DNA observed by Harris et al. (1976) strongly suggest that there may be little basis for screening humans for variations in lymphocyte aryl hydrocarbon hydroxylase activity as a means of assessing their susceptibility to lung cancer.