Ectopic expression of RKIP suppressed BT20 cell invasion, while concurrent sub-optimal knockdown of E-cadherin expression reversed the inhibitory effect on invasion due to the expression of RKIP indicating the increase in E-cad expression is required for the RKIP-mediated suppression of breast cancer cell in vitro invasion (Fig. 3c). This evidence concerns the gene PEBP1 and breast cancer.