MORPHOLOGICAL TRANSFORMATION OF C3H M2 MOUSE FIBROBLASTS BY EXTRACTS OF HUMAN MAMMARY LIPID/

Mammary lipid may act as a reservoir for genotoxins. Mammary lipid ext racts (MLEs), obtained from eight UK women (21-41 years) undergoing re duction mammoplasty, were examined for their abilities to morphologica lly transform C3H/M2 mouse fibroblasts. Resultant transformation rates were 0.27, 0.33, 0.07, 0.29, 0.21, 0.00, 0.07, and 0.13 transformed f oci/treated dish, respectively. Although the lipid-extraction procedur e used was originally designed to extract heterocyclic aromatic amines (HAAs), Liquid chromatography/mass spectroscopy (LC/MS) with selectiv e ion monitoring has failed to detect HAAs in any of the lipid extract s so far examined. Genotoxicities were also assessed in S. typhimurium TA98 and in metabolically competent human (MCL-5) cells by the micron ucleus and by the alkaline single-cell gel (''comet'') assays. The MLE s induced bacterial mutagenicity rates ranging from 0 to 498 revertant s/plate/g-lipid equivalent and micronucleus-formation rates from 0 to 20 micronuclei/500 binucleate cells/g-lipid. Median comet tail lengths (induced with MLEs of 8.0 g-lipid equivalent) ranged from 6.0 to 74.0 mu m. The results demonstrate the presence of as-yet-unidentified tra nsforming agents in mammary Lipid. (C) 1998 Academic Press.