COPB2 is the main representative of β'‐COP in the COPI complex, which is built up of seven subunits: α‐COP (COPA), β‐COP, γ‐COP, δ‐COP, β'‐COP (COPB), ε‐COP and ξ‐COP (COPZ) and COPB2 were among the definite features in the protein collaboration network.17 Gordon et al18 showed that mRNA expression was increased in mesothelioma tissues, which was explained by one of the subunits in COPI along with large scale transcription profile. This evidence concerns the gene PSMB5 and mesothelioma.