ERAP1 and non-small cell lung carcinoma: Given the limited and inconsistent data on ERAP1 expression in the context of NSCLC, it will be essential to conduct in-depth studies first to determine ERAP1 expression at the protein level, secondly to find out whether there is a correlation between ERAP1 mRNA and protein expression levels, and finally what mechanisms are responsible for the regulation of ERAP1 protein expression and the reduced mRNA expression observed in the tumor tissue in our study.