Effects of EGF treatment on EL4 cell invasion. Equal numbers (1 × 105) of EL4 cells were plated in the upper chamber of 8-micron trans-well insert coated with 20 μg Matrigel. To the bottom chamber the following chemoattractants were added in serum-free medium: Control, 0.1% BSA; Serum, 10% FBS; EGF, 10 nM EGF. (a) After 24 hours, invaded cells were stained with Diff-Quik, photographed. (b) Migrated cells were quantified by cell counting. Data are plotted as percent of BSA control; each data point represents mean ± SD for three wells of cells. Statistical significance was determined using t-test: * p < 0.05.