Following stimulation by TNFα, breast tumor cells acquire increased adhesive, migratory and invasive properties. MCF-7 breast carcinoma cells were stimulated by TNFα (1000 U/ml). Thereafter, the following analyses were performed: (a) Following 72 hr stimulation by TNFα, adhesion to substrate was determined by alkaline phosphatase assay. **p = 0.005 for the difference between cells that were stimulated or not stimulated by TNFα. (b, c) Determination of the ability of the cells to perform migratory and invasive activities, in response to serum. Following 48 hr stimulation by TNFα (1000 U/ml), migration and invasion assays were performed in transwells for 21-23 hr with or without TNFα stimulation. (b) Migration. ***p < 0.001 for TNFα-stimulated cells vs. non-stimulated cells. (c1) Invasion counts. ***p < 0.001 for TNFα-stimulated cells vs. non-stimulated cells. (c2) Invasion as demonstrated in light microscopy. HPF = High Power Field. In all parts of the figure, experiments are representatives of n = 3.