Review of the genotoxicity and carcinogenicity of 4,4'-methylene-dianiline and 4,4'-methylene-bis-2-chloroaniline.

4,4'-Methylene-dianiline (MDA) and 4,4'-methylene-bis-2-chloroaniline (MOCA) are polycyclic aromatic amines that are currently used in industry. Both compounds have been found to be bacterial mutagens and to be positive in a number of assays for genotoxicity. In animal studies, MDA has induced thyroid and liver neoplasms while exposure to MOCA resulted in a variety of tumors including those of the liver, mammary gland and bladder. Epidemiologic proof of human carcinogenicity of both compounds is lacking; however, there is evidence that MOCA can be metabolized to mutagenic products by human tissue. In this paper, the major finding concerning the biotransformation, genotoxicity and carcinogenicity of MDA and MOCA are reviewed.