Morgan et al. BMC Cancer 2010, 10:89 http://www.biomedcentral.com/1471-2407/10/89 Page 3 of 9 three mice at 3, 12 and 24 hours after iv administration of 100 mg/Kg HXR9. Total cellular protein was extracted and 10 μg were dot blotted on nitrocellulose membrane and probed with a rabbit polyclonal anti- HXR9 antibody. Quantification was achieved using a standard series of HXR9 dilutions. Statistical analysis Data are given as means ± SEM of at least three inde- pendent experiments. Significant effects were deter- mined by 2-tailed Student’s t tests (p < 0.05), or the Mann-Whitney test for mouse tumour modelling experiments. For the analysis of the QPCR for HOX gene expression the Bonferroni correction was applied to account for multiple comparisons. There are 39 HOX genes thus the limit for a significant result is p < 0.0013. Results Hox gene expression in normal ovarian tissue and ovarian cancer cell lines Previous studies have examined the expression of HOX genes in ovarian tumours but to date this had not been done in a comprehensive manner, looking at all 39 members of this family. Thus, we measured the relative expression of HOX genes in normal ovarian tissue and in the derived cell lines SK-OV3 and OV-90 using semi-quantitative PCR (Fig 1). This revealed that multi- ple HOX genes had a dysregulated pattern of expression in SK-OV3 cells, but generally not in OV-90 cells, in comparison to the normal ovary. In SK-OV3 the A family of the HOX genes showed a statistically signifi- cant up regulation of HOXA5, HOXA9, and HOXA13. The HOXB and HOXD families were mainly expressed Figure 1 HOX gene expression in normal ovary and in the ovarian cancer derived cell lines SK-OV3 and OV-90 cells. Gene expression was determined by QPCR and expressed as a ratio to the amount of expression of the housekeeping gene, b-actin. Abbreviations are used for each HOX gene shown on the x-axis such that, for example, HOXA1 is represented by ‘A1’. SEM is indicated by the error bars. P-values of less than 0.0013 (Bonferroni correction for multiple hypothesis testing) for expression in SK-OV3 cells compared to that in normal ovary are denoted *.