APEX1 and mesothelioma: In light of previous data, we primarily performed experiments to confirm Ref-1 overexpression in MSTO-211H mesothelioma cells toward Met-5A mesothelial untransformed cells, and the NSCLC cellular model was used as a positive control of Ref-1 overexpression; as expected, we clearly stated significant Ref-1 overexpression in MSTO-211H and A549 cells, but not in Met-5A untransformed mesothelial cells.