Prognostic value of immune-related genes and comparative analysis of immune cell infiltration in lung adenocarcinoma of different genders

Abstract Background Lung adenocarcinoma (LUAD) is one of the most important subtypes of lung cancer. Compared with male LUAD patients, female patients have a higher incidence, but better long-term survival rate, with unknown reasons. In this study, we aimed to explore the effect of gender on immune cell infiltration of LUAD tumor microenvironment (TME), and tried to clarify the reasons for the different clinical characteristics of male and female LUAD patients, by conducting a comparative analysis of the TME in female and male LUAD patients. Methods We calculated immune and stromal scores of LUAD patients samples from The Cancer Genome Atlas (TCGA) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted to reveal biological processes of intersecting genes. Cox regression analysis and protein-protein interaction (PPI) network analysis were conducted to screen immune-related prognostic genes in female (CCR2, LCP2, and PTPRC) and male (BTK and CCR2) patients. Kaplan-Meier survival analysis was used to evaluate prognostic value of identified genes. Mann-Whitney test was used to compare various indicators of male patients and female patients. The main result was subsequently validated in 420 cases from GSE72094. Results 304 and 368 intersecting genes were identified in female and male patients respectively. The immune score is ranged from − 943.17 to 3229.35 among female patients with LUAD and from − 541.75 to 3441.78 among male patients with LUAD. The stromal score is ranged from − 1790.23 to 2097.27 among female patients and from − 1786.94 to 1722.70 among male patients. The immune and stromal scores of women were higher than those of men (P < 0.05). CCR2, LCP2 and PTPRC were identified as the most important immune-related prognostic genes in women. BTK and CCR2 were identified as the most important immune-related prognostic genes in men. Female patients had a higher proportion of memory B cells than that of male patients, while the percentage of T cells CD4 naïve and resting NK cells was lower in female patients (P < 0.05). Conclusions This study compared the differences in TIICs in the TME of male and female LUAD patients, and identified prognosis-related genes for patients of different genders.