Abstract
High-grade soft-tissue sarcoma (STS) is a highly malignant neoplasm with a poor overall prognosis. Numerous prognostic factors determine tumor progression and patient outcomes. Various immune-associated cells identified in the tumor microenvironment have important roles in various tumor types. The present study was performed to evaluate the expression of immune-associated genes and to elucidate the association between these genes and the prognosis in high-grade STS. A total of 12 formalin-fixed, paraffin-embedded tissue samples of high-grade STS were subjected to gene expression analysis using the NanoString nCounter® System and another 35 samples were used for immunohistochemistry. For comparative analysis, the patients were divided into two groups according to overall survival (OS). The expression levels of 770 genes were first analyzed using the nCounter® PanCancer Immune Profiling Panel. Immunohistochemistry was then performed for the most significantly altered genes. Subsequently, the association between gene expression and prognosis of high-grade STS was evaluated. Of the 770 immune-associated genes analyzed, several genes were identified as being differentially expressed between the two groups. Based on gene expression levels and fold change, 13 representative genes were identified; 7 of the 13 candidate genes (C3, CD36, DOCK9, FCER2, FOS, HLA-DRB4 and NCAM1) were significantly overexpressed in the poor prognosis group, while the other 6 immune-associated genes (BIRC5, DUSP4, FOXP3, HLA-DQA1, HLA-DQB1 and LAG3) were increased in the good prognosis group. By immunohistochemistry, the expression of the 13 immune-associated genes was confirmed to be significantly different between the two groups. Expression of HLA-DQA1, HLA-DQB1 and HLA-DRB4 was observed in 74.3, 34.3 and 48.6% of tumors, respectively. HLA-DQA1 and HLA-DQB1 were significantly decreased, whereas HLA-DRB4 was significantly increased in the poor prognosis group. Of note, expression of HLA-DQA1 was associated with a significantly longer OS (P=0.028). In conclusion, HLA-DQA1 expression was significantly associated with long-term survival and may therefore be an immune biomarker for good prognosis in high-grade STS.