Three mesothelioma cell lines (MS-1, H2452 and 211H) with increased Cul4A copy number were treated with Cul4A siRNA for 48 hr and greater than 90% reduction in Cul4A mRNA was detected in all cell lines when compared to controls (*P < 0.05, t-test; Fig. S2A). This evidence concerns the gene CUL4A and mesothelioma.