Some GROs have been reported to induce apoptosis in tumor cells21,47,48 and induce the accumulation of cells in S phase and in sub-G1 phase.20,41,47 In order to further compare the effects of guanine-based compounds and GROs on cell cycle and apoptotic profile, we performed Annexin V-fluorescein assay and cell cycle assay after treating cells with 10 μM TT-loop, de-TT-loop (TT-loop pretreated in 50% serum for 48 h), AS1411 or different concentrations of dG for different times. This evidence concerns the gene ANXA5 and neoplasm.