Quantitative analysis of the tumor cells invasion assay shown in Figure 1. A. The area above and below the cell monolayer was divided into three subsequent 120 μm wide zones as shown in Figure 1A. The number of invading cells in each of the zones was determined at three day intervals as described in methods. Each point represents the average number of cells counted in at least eight different microscopic fields derived from three separate experiments. B. The average number of each of the tumor cell types was determined as a function of time following monolayer formation in microscopic fields using the image-pro software as described in methods. C. The number of cells that have invaded each of the zones as a function of time is presented here as a percentage out of the total number of cells. Error bars represent the standard error of the mean.