S; (SPR): Surface plasmon resonance; (Ph) chromosome: Philadelphia; (PBMC): Peripheral blood mononuclear cells; (AUC): Area

S; (SPR): Surface plasmon resonance; (Ph) chromosome: Philadelphia; (PBMC): Peripheral blood mononuclear cells; (AUC): Area under the curve. Acknowledgements This work received the financial support of FCT/MCES through grants to CIGMH-FCT/UNL, PTDC/BIO/66514/2006 and PTDC/SAU-BEB/66511/2006. We thank Dr. A.S. Rodrigues for the human cell lines (K562 and HL-60) and M. Mateus for blood samples. Author details 1 CIGMH, Departamento de Ci cias da Vida, Faculdade de Ci cias e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. 2Instituto de Nanociencia de Arag , Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain. Authors’ contributions JC participated in the sequence alignment and design of the nanoprobe, carried out the nanoprobe synthesis, and performed the detection assays. JF participated in the design of the study. PB conceived the study, participated in its design and coordination, and drafted the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 23 November 2009 Accepted: 24 February 2010 Published: 24 February 2010 References 1. National Cancer Institute: [http://nano.cancer.gov/]. 2. Mirkin CA, Letsinger RL, Mucic RC, Storhoff JJ: A DNA-based method for rationally assembling nanoparticles into macroscopic materials. Nature 1996, 382(6592):607-609. 3. Storhoff JJ, Lucas AD, FCCP web Garimella V, Bao YP, Muller UR: Homogeneous detection of unamplified genomic DNA sequences based on colorimetric scatter of gold nanoparticle probes. Nat Biotechnol 2004, 22(7):883-887. 4. Thaxton CS, Georganopoulou DG, Mirkin CA: Gold nanoparticle probes for the detection of nucleic acid targets. Clin Chim Acta 2006, 363(12):120-126. 5. Baptista P, Pereira E, PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/25447644 Eaton P, Doria G, Miranda A, Gomes I, Quaresma P, Franco R: Gold nanoparticles for the development of clinical diagnosis methods. Anal Bioanal Chem 2008, 391(3):943-950. 6. Baptista P, Doria G, Henriques D, Pereira E, Franco R: Colorimetric detection of eukaryotic gene expression with DNA-derivatized gold nanoparticles. J Biotechnol 2005, 119(2):111-117.7.8.9.10.11. 12.13. 14. 15. 16.17. 18.19.20.21.Baptista PV, Koziol-Montewka M, Paluch-Oles J, Doria G, Franco R: Goldnanoparticle-probe-based assay for rapid and direct detection of Mycobacterium tuberculosis DNA in clinical samples. Clin Chem 2006, 52(7):1433-1434. Costa P, Amaro A, Botelho A, In io J, Baptista PV: Gold nanoprobes assay for identification of mycobacteria from the Mycobacterium tuberculosis complex. Clin Microbiol Infect 2009. Doria G, Franco R, Baptista P: Nanodiagnostics: fast colorimetric method for single nucleotide polymorphism/mutation detection. IET Nanobiotechnol 2007, 1(4):53-57. Griffin J, Singh AK, Senapati D, Lee E, Gaylor K, Jones-Boone J, Ray PC: Sequence-specific HCV RNA quantification using the size-dependent nonlinear optical properties of gold nanoparticles. Small 2009, 5(7):839-845. Hehlmann R, Hochhaus A, Baccarani M: Chronic myeloid leukaemia. Lancet 2007, 370(9584):342-350. Shet AS, Jahagirdar BN, Verfaillie CM: Chronic myelogenous leukemia: mechanisms underlying disease progression. Leukemia 2002, 16(8):1402-1411. Ren R: Mechanisms of BCR-ABL in the pathogenesis of chronic myelogenous leukaemia. Nat Rev Cancer 2005, 5(3):172-183. Wong S, Witte ON: The BCR-ABL story: bench to bedside and back. Annu Rev Immunol 2004, 22:247-306. Melo J: Inviting leukemic cells to waltz.