This may be an underestimate, given that (i) FISH analysis of clinical tissue sections was done in interphase, (ii) visualizing the locations of FISH probes in clinical tissue sections is difficult and (iii) 6/6 of mesothelioma cell lines showed increased Cul4A copy number (3–4 copies) by FISH (Fig. 2C and D). This evidence concerns the gene CUL4A and mesothelioma.