NUCLEOLIN and cancer: However, two aptamers are in clinical trials for cancer therapy: i) AS1411, a DNA quadruplex aptamer against nucleolin, an ubiquitous intranuclear and cytoplasmic phosphoprotein involved in the regulation of cell proliferation, often over-expressed on the surface of tumour cells; and ii) NOX-A12, a Spiegelmer that binds and neutralizes CXCL12 chemokine, which has a crucial role in cell growth and migration [95].