In conclusion, the use of a varied panel of eight mesothelioma cell lines and the investigation of a large number of tumour samples from patients with mesothelioma treated with pemetrexed in this study demonstrate that there is no relationship between response to pemetrexed and FRα expression in mesothelioma, or to the expression of RFC and PCFT in the cell lines. Here, FOLR1 is linked to mesothelioma.