Immune Score Closely Associated With Tumor Microenvironment as A Prognostic Factor in Lung Adenocarcinoma
Abstract Background: The tumor microenvironment plays a vital role in tumor biology and has recently attracted widespread attention. However, the prognostic significance of integrated immune scores in lung adenocarcinoma has not yet been identified. This study aimed to systematically estimate the association between immune scores and prognosis and develop a clinical nomogram to predict the survival of patients with lung adenocarcinoma. This study also systematically explored the underlying prognostic factors of the immune score in lung adenocarcinoma.Methods: Public datasets for lung adenocarcinoma was acquired from The Cancer Genome Atlas data portal. The immune score of each sample was calculated using the ESTIMATE algorithm. Univariate and multivariate Cox regression analyses identified several significant prognostic factors and further developed a prognostic nomogram. The C-index, calibration curve, and ROC curve were used to evaluate the predictive accuracy and discriminative ability of the resultant nomogram. Results: We found that patients with higher immune scores had a better prognosis (log rank test p = 0.0004). The nomogram that integrated the immune score could effectively stratify high-risk LUAD patients in terms of clinical response. Patients in the high-risk groups usually had a worse prognosis (log rank test p < 0.0001) and higher mortality. The mortality rate in high and low risk groups was 42.67% and 26.37%, respectively (p < 0.0001). In addition, correlation analysis showed that the immune score was significantly dependent on the mRNA expression of immunotherapy-associated biomarkers (PD-1, PD-L1, and LAG3) as well as on the presence of certain immune cell subtypes, but had no correlation with tumor mutation burden.Conclusion: The immune score is a prognostic factor in lung adenocarcinoma. The nomogram with an integrated immune score can effectively predict the survival of patients with lung adenocarcinoma. The mechanism by which the immune score estimates the prognosis of patients with lung adenocarcinoma is related to the tumor immune microenvironment.