Fig. 1

Expression of HOX genes in cell lines derived from mesothelioma (a) and (b) primary mesothelioma tumors. These genes were previously shown to function as either oncogenes or tumor suppressors (see Table 1 for more detail). The relative levels of RNA for each gene are shown as a ratio with Beta-actin (×10000 for NCI-H28, NCI-H2052 and NCI-H226, ×100 for primary mesothelioma tumors, Met-5A, and MSTO-211). For the cell lines (a) each value is the mean of three experiments, and error bars show the SEM. For the primary tumors (b) the expression of each HOX gene is shown for each individual tumor. The values shown are the mean of three technical repeats. No error bars are included in order to simplify the figure, although all repeats were within 10 % of the mean value. For three of the HOX genes, (HOXA4, HOXA9, and HOXB4), the protein expression was also determined using immunohistochemistry and an example of each staining from a single tumor is shown. Scale bar: 20 μm. Neg, negative – no primary antibody. c HOXB4 tumor expression, as determined using quantitative real-time PCR, is significantly higher amongst patients surviving for less than 6 months after diagnosis (values on the y-axis are the ratio of HOXB4 to Beta-actin expression × 10000). d HOXB4 expression is associated with a shorter overall survival. Kaplan-Meier survival curves for patients with high- and low-HOXB4 expressing tumors (p = 0.041). The cut-off point between high- and low-expression was determined as the midpoint between the mean values of HOXB4 expression shown in (c), which was 53