Objective:Pseudogenes are initially regarded as nonfunctional genomic sequences,but some pseudogenes regulate tumor initiation and progression by interacting with other genes to modulate their transcriptional activities.Olfactory receptor family 7 subfamily E member 47 pseudogene(OR7E47P)is expressed broadly in lung tissues and has been identified as a positive regulator in the tumor microenvironment(TME)of lung adenocarcinoma(LUAD).This study aimed to elucidate the correlation between OR7E47P and tumor immunity in lung squamous cell carcinoma(LUSC).Methods:Clinical and molecular information from The Cancer Genome Atlas(TCGA)LUSC cohort was used to identify OR7E47P-related immune genes(ORIGs)by weighted gene correlation network analysis(WGCNA).Based on the ORIGs,2 OR7E47P clusters were identified using non-negative matrix factorization(NMF)clustering,and the stability of the clustering was tested by an extreme gradient boosting classifier(XGBoost).LASSO-Cox and stepwise regressions were applied to further select prognostic ORIGs and to construct a predictive model(ORPScore)for immunotherapy.The Botling cohorts and 8 immunotherapy cohorts(the Samstein,Braun,Jung,Gide,IMvigor210,Lauss,Van Allen,and Cho cohorts)were included as independent validation cohorts.Results:OR7E47P expression was positively correlated with immune cell infiltration and enrichment of immune-related pathways in LUSC.A total of 57 ORIGs were identified to classify the patients into 2 OR7E47P clusters(Cluster 1 and Cluster 2)with distinct immune,mutation,and stromal programs.Compared to Cluster 1,Cluster 2 had more infiltration by immune and stromal cells,lower mutation rates of driver genes,and higher expression of immune-related proteins.The clustering performed well in the internal and 5 external validation cohorts.Based on the 7 ORIGs(HOPX,STX2,WFS,DUSP22,SLFN13,GGCT,and CCSER2),the ORPScore was constructed to predict the prognosis and the treatment response.In addition,the ORPScore was a better prognostic factor and correlated positively with the immunotherapeutic response in cancer patients.The area under the curve values ranged from 0.584 to 0.805 in the 6 independent immunotherapy cohorts.Conclusion:Our study suggests a significant correlation between OR7E47P and TME modulation in LUSC.ORIGs can be applied to molecularly stratify patients,and the ORPScore may serve as a biomarker for clinical decision-making regarding individualized prognostication and immunotherapy.