Lavage and nipple aspiration of breast ductal fluids: a source of biomarkers for environmental mutagenesis.

The acquisition of breast ductal fluid by nipple aspiration and ductal lavage are simple noninvasive procedures to sample breast tissue. Nipple aspiration fluid (NAF) obtained with gentle suction and a simple syringe-adapted apparatus may evaluate the secretory components that bathe the ductal epithelial cells. Evaluations have included the quantification of soluble markers (carcinoembryonic antigen and prostatic-specific antigen), DNA amplification, protein gel electrophoresis, and mutagenesis assays. It has been suggested that environmental mutagens in the breast ductal system may contribute to carcinogenesis. The feasibility of mutagenesis assays on NAF has been limited by the small size of the samples obtained. Three small clinical studies detected mutagens in 6-14% of the samples using the Salmonella Ames assay. Ductal lavage collects more of a cellular aspirate from the ductal system utilizing a microcatheter. Early studies on ductal lavage fluid have included cytology and methylation-specific PCR. Ductal lavage in a high-risk group has identified cellular atypia in 21% of those sampled. Samples obtained through the nipple, by aspiration or lavage, are the proteinaceous secretions from the ductal system and ductal epithelial cells. The fluid represents the cellular events and the dynamic secretory process of the breast and may include potential initiators of the carcinogenesis process in the cellular microenvironment. Fluid obtained by ductal lavage may allow for more detailed studies of the role of mutagens in breast cancer.