Correlation of Cystatin E/M with Clinicopathological Features and Prognosis in Triple-Negative Breast Cancer.

Background: Among all kinds of breast cancer, triple-negative breast cancer (TNBC) is the most aggressive, with the poorest prognosis and highest mortality rates. Thus, novel biomarkers that personalize the therapeutic regimen and evaluate prognosis for TNBC patients should be determined.
Methods: We analyzed the cystatin E/M (CST6) expression profiles of 161 TNBC tissues and 14 noncancerous tissues through multiple statistical analyses. We also investigated the relationship of CST6 expression with clinical parameters and evaluated the prognostic value of CST6 in 161 TNBC patients.
Results: CST6, a member of the cystatin superfamily, was remarkably more up-regulated in TNBC tissues than in adjacent normal breast tissues. High CST6 expression was frequently observed in white people and associated with a high risk of lymph-node metastasis. Cox regression analysis confirmed that the high CST6 expression was an independent predictor of disease-free survival in TNBC. Kaplan-Meier analysis further revealed that high CST6 expression caused a low disease-free survival rate.
Conclusion: CST6 is involved in the progression of TNBC and may act as a tumor-promoter gene. A systematic literature review shows that our study is the first to explore the relationship between CST6 and TNBC.
(© 2018 by the Association of Clinical Scientists, Inc.)