NUCLEOLIN and neoplasm: Underscoring the broad utility of the nucleolin aptamer as tumor-targeting ligand for siRNA delivery, measuring mRNA (Fig. 1a) or MHC class I downregulation (Fig. 1b), antigen presentation in vitro (Fig. 1c, d), CTL induction (Fig. 4f–i), or tumor inhibition in mice (Fig. 3), and in vitro studies in human tumor cells (Fig. 6), the TAP siRNA was delivered to multiple murine and human tumor cells of distinct origin.