Among these proteasome subunits, PSMB3 [35] and PSMD14 [36] have been found to promote lung adenocarcinoma progression, while PSMA4 polymorphisms are associated with lung cancer susceptibility and response to cisplatin-based chemotherapy [37], suggesting that the proteasome may be associated with the LUAD progression and drug response due to numerous subunits. This evidence concerns the gene PSMA4 and lung cancer.