Based on these findings, we hypothesized that siRelA with MPEG-PCL-CH2R4H2C could inhibit cell-adhesion between migrating cancer cells and vascular endothelial cells by inhibiting the expression of RelA through gene silencing with siRelA, and therefore improve tumor accumulation and the silencing effect of MPEG-PCL-CH2R4H2C through systemic administration. This evidence concerns the gene RELA and cancer.