In a quest to find a target which is broadly expressed among most of the tumors, especially the most aggressive ones, and which may target key cells that are critical for chemotherapy resistance and tumor progression (cancer stem-like cells), we selected through a combinatorial peptide-Cell High Throughput (HT) SELEX an aptamer against the extracellular exposed motif of MRP1. This evidence concerns the gene ABCC1 and neoplasm.