The long-term exposure of MCF-12A cells to low dose ethanol or to acetaldehyde induces anchorage-independent growth as assessed by the soft agar assay. Monolayer cultures were maintained in triplicate for 4 weeks in the presence of or absence of 1 or 2.5 mM ethanol, or 1 mM acetaldehyde, as indicated, and then cells were transferred to soft agar for 2–3 weeks growth in triplicate on Petri dishes in the absence of added ethanol or acetaldehyde. Foci were stained with methylene blue (top, representing 1 mM ethanol cultures), photographed, and then counted (bottom). ***p<0.001.