Luo D, et al. - Researchers examined the roles of tissue and circulating microRNA-21 (miRNA-21) and SNHG1 (small nucleolar RNA host gene 1) in ESCC patients, especially focusing on the features of miRNA-21 and SNHG1 expression as well as their associations with survival rates, and their interaction with each other in ESCC. They found significant upregulation of the expression level of miRNA-21 and SNHG1 in tissues, serum and cell lines of ESCC. In ESCC patients, they identified a significant correlation of tissue miRNA-21 and SNHG1 with lymph node metastasis, TNM stage, tumor size, and poor overall survival. For serum miRNA-21 and SNHG1, areas under the ROC curve (AUC) were 0.928 and 0.850, respectively, as demonstrated by ROC curves. In ESCC patients, miRNA-21 and SNHG1 were identified as independent prognostic factors for overall survival and disease-free survival in Cox univariate and multivariate analyses. According to the findings, SNHG1 may represent a new downstream target of miRNA-21 and not vice versa in ESCC cells. The results also showed a significant contribution of SNHG1 toward the proliferation of ESCC cells. The possible utility of miRNA-21 and SNHG1 as potential diagnostic, prognostic biomarkers and treatment targets for ESCC patients was suggested.