Prognostic significance of Ubiquilin1 expression in invasive breast cancer.

Objective: To explore the correlation between Ubiquilin1 (UBQLN1) expression and clinicopathological characteristics and determine its prognostic significance in patients with breast cancer.

Methods: UBQLN1 expression was evaluated by immunohistochemistry in 125 invasive breast cancer samples. The association between UBQLN1 and clinicopathological parameters and prognosis of breast cancer were detected.

Results: The UBQLN1 protein was overexpressed in breast cancer samples (68/125) and associated with tumor size (P = 0.034), lymph node metastasis (P = 0.035), TNM stage (P = 0.049) and vascular invasion (P = 0.003). The DFS and OS rates at 5 years were 27.7% and 48.7% for UBQLN1 positive patients compared with 49.6% and 77.4% for UBQLN1 negative patients, respectively (both P = 0.001). Multivariate analyses revealed that UBQLN1 was an independent prognostic factor for overall survival (hazard ratio, 2.416; 95% CI, 1.134-5.149, P= 0.022) and disease-free survival (hazard ratio, 2.113; 95% CI, 1.203-3.709, P= 0.009). Furthermore, UBQLN1 overexpression was associated with poor prognosis in patients without lymph node metastasis (DFS 35 months vs 62 months, P = 0.005; OS 68 months vs 72 months, P = 0.017).

Conclusions: The expression level of UBQLN1 and prognosis in breast cancer is clarified for the first time and UBQLN1 seems to be a novel molecular marker to predict poor prognosis in breast cancer.