To validate the immunohistochemical results of eight frozen representative cases, Yen et al. used reverse-transcription PCR and observed that the PCR product of mesothelin was strongly representative of tumours with diffuse mesothelin immunoreactivity (4+ and 3+ positivity) (Figure 1A,B), while it was barely detectable in negative tumours (score: 0) (Table 1). The gene discussed is MSLN; the disease is neoplasm.