Prognostic values of EDNRB in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has a high degree of malignancy. The endothelin B receptor (EDNRB) serves an important role in the occurrence and development of cancer. The present study aimed to investigate the prognostic value of EDNRB in TNBC. A total of 99 cases of TNBC were collected from the Henan Cancer Hospital database and 159 cases of TNBC were collected from The Cancer Genome Atlas database. A χ² test was used to analyze the association between EDNRB and clinicopathological data. Kaplan-Meier analysis and multivariate Cox regression analysis were used to analyze the association between EDNRB and prognosis, and to establish two models. The discrimination degree of the models was evaluated using time-dependent receiver operating characteristic curves and concordance index (C-index), whereas the accuracy and net benefit of the models were evaluated using integrated discriminant improvement (IDI) and decision curves. EDNRB expression was low in TNBC samples (P<0.01). Age (P=0.01), tumor size (P=0.04) and N stage (P=0.01) were associated with EDNRB expression. EDNRB expression was positively associated with stromal score (P<0.01), but not immune score. High expression levels of EDNRB indicated favorable disease-free survival time (hazard ratio, 0.38; 95% CI, 0.15-0.98; P=0.04). The integrated area under the curve and C-index of the new model were increased compared with the old model following the addition of EDNRB expression as a parameter. The IDI values for prediction of the 3- and 5-year survival rates were 0.04 (P=0.02) and 0.05 (P=0.01), respectively. The results of decision curve analysis showed that the new model had higher clinical net benefit than the old model in the range of 3-year survival rate <0.52. In conclusion, EDNRB was associated with a favorable prognosis in patients with TNBC, and may be used as a novel prognostic biomarker.