ZEB1 and mesothelioma: The singular situation of the M5-T2 cell line was reinforced by the observation of a maximum expression of five other genes, Rassf1, Zeb1, Vim, Acta2 and Tgfb1, which was common to the PNsarc group, in contrast with the three invasive mesothelioma cell lines which presented significantly lower expression levels.