CXCL12 and neoplasm: Noxxon Pharma AG has developed an l-RNA (Spiegelmer) aptamer (NOX-A12) that binds to the chemokine (C-X-C motif) ligand 12 (CXCL12; Darisipudi et al., 2011), a ligand involved in tumor metastasis, cell homing, and angiogenesis (Keefe et al., 2010).