Figure 1

14q32 miRNA expression levels and metastasis in human osteosarcoma. (A) Correlation network of 14q32 miRNAs expression in human osteosarcoma samples. Correlation network was constructed with Pearson correlation R >0.9 as the edges. The resulting correlation sub-network contained thirty-six miRNAs and 33 of them mapped to the 14q32 locus. All pairwise correlations used to generate this image are given in Additional file 8: Table S7. (B) Microarray based transcript levels of highly correlated 14q32 miRNAs in osteosarcoma tumors shown relative to the level observed in FT-14 (human osteosarcoma primary tumor). miRNA profiling data from human osteosarcoma tumors where metastasis was observed show stronger downregulation of 14q32 miRNAs (highlighted in red) than primary osteosarcoma tumors where metastasis was not observed. (C) Microarray based transcript levels for miR-382 and miR-154. miR-382 and miR-154 show a high level of correlation (R² = 0.95). (D) qRT-PCR validation for miR-382 and miR-154 expression levels obtained in primary osteosarcoma tumors (FT-14, -7) where metastasis was not observed and three primary osteosarcoma tumors with low levels of (FT-18, -13, -12) where metastasis was observed. miR-382 and miR-154 show a high level of correlation (R² = 0.99). Measurements were carried out in triplicate and were normalized to the expression levels in two independent normal bone tissues that were also carried out in triplicate.