Abstract
OBJECTIVE: The aim of this study was to construct the immunoscore (IS) to facilitate the prediction of postoperative survival and benefit from adjuvant chemotherapy (ACT) in esophageal squamous cell carcinoma (ESCC). METHODS: A total of 249 patients who received radical esophagectomy at Fudan University Shanghai Cancer Center were divided into training set and testing set. Eighty-nine patients with ESCC from TCGA database were enrolled into the validation set. Myeloid cells in tumor microenvironment were evaluated by immunohistochemistry or CIBERSORT, and then were included into a LASSO Cox regression model to construct the immunoscore. The predictive value of the immunoscore for prognosis after surgery or ACT was analyzed. RESULTS: The immunoscore was constructed by four types of myeloid cells including macrophages, neutrophils, mast cells, and dendritic cells and was demonstrated as IS=2^(0.527719*Mφ -0.2604269*MC-0.4812935*DC-0.4519706*Neu). The overall survival was significantly different between two immunotypes, which were divided according to the immunoscore, in all sets (P<0.001, P=0.005, and P=0.002, respectively). Immunotype A was identified as an independent predictor for survival benefit in all three sets (HR=2.068, P=0.005; HR=2.028, P=0.007; HR=6.474, P=0.007; respectively). In patients who received ACT, immunotype A was significantly related to longer overall survival both in the training set (P<0.001) and in the testing set (P=0.011). The nomogram based on immunotype and other clinicopathological factors showed good efficiency of predicting response to ACT. Finally, several important cytokines and pathways were highly enriched in immunoscore A subgroup. CONCLUSION: The immunoscore was an effective prognostic predictor in ESCC for patients undergoing surgical resection and receiving ACT.