ELF5 gene rearrangements have been described in several lung cancer cell lines [5], and the authors of a recent case study described a ZFPM2-ELF5 fusion gene in multicystic mesothelioma [22]; however, gene fusions do not appear to be a major mechanism for deregulation of ELF5, in contrast to other ETS factors, such as TMPRSS2-ERG/ETV1 fusions in prostate cancer [23]. This evidence concerns the gene ELF5 and peritoneal multicystic mesothelioma.