We investigated possible cytotoxic effects produced by ZOL or Ad-delE1B55 on 5 kinds of mesothelioma, MSTO-211H, NCI-H226, NCI-H28, EHMES-10 and NCI-H2452 cells, which are defective of the p14ARF and p16INK4A genes or the transcription but possess the wild-type p53. Cells treated with ZOL showed decreased viability with a similar level (Fig. 1a), whereas the sensitivity to Ad-delE1B55 was different among the cells and EHMES-10 cells were resistant (Fig. 1b). Here, CDKN2A is linked to mesothelioma.