High expression of PTGES3 is an independent predictive poor prognostic biomarker and correlates with immune infiltrates in lung adenocarcinoma

BACKGROUND: Immune-infiltration was positively relationship with overall survival in lung adenocarcinoma (LUAD). Nevertheless, the potential clinical value of PTGES3, especially in terms of prognosis and tumor immune-infiltration in LUAD had not been fully elucidated. METHODS: Original data available from TCGA and GEO databases and integrated via R3.6.3. Kaplan-Meier and Cox regression methods were used to examine the effect of PTGES3 expression in overall survival, and nomogram was performed to illustrate the correlation between the PTGES3 expression and the risk of LUAD. The associate between PTGES3 and cancer immune characteristics were analyzed via the TISIDB databases. Western blot and RT-qPCR were used to analyze PTGES3 expression in the clinical lung adenocarcinoma tissue samples or non-small cell lung cancer cell lines. RESULTS: PTGES3 mRNA and protein expression were significantly elevated in LUAD compared with normal lung tissues. Up-regulated PTGES3 was significantly associated with pathologic stage and TM stage. Kaplan-Meier survival analysis and subgroup analysis showed that up-regulated PTGES3 was associated with a worse overall survival of LUAD (HR = 1.71 (1.27-2.31), p < 0.001). Multivariate Cox analysis showed that high PTGES3 expression was an independent factor affecting overall survival (HR = 1.64 (1.14-2.37), p < 0.001). GO and KEGG analysis revealed that the cell cycle, regulation of DNA replication, and regulation of innate immune response were enriched. A positive correlation between PTGES3 expression and immune infiltrating levels of Th2 cells was found. CONCLUSION: PTGES3 may play an important role in the cell cycle and as an independent predictive prognostic biomarker correlates with immune infiltrates in lung adenocarcinoma.