Objective To investigate the expression of Ubiquilin1(UBQLN1) protein in breast cancer tissues and its prognostic significance.

Methods Immunohistochemistry for UBQLN1 expression was performed on 108 cases of breast cancer specimens. Additionally, the relationship between UBQLN1 expression and clinicopathological features, recurrence, metastasis, survival time was analyzed.

Results The positive expression rate of UBQLN1 in breast cancer tissues was 50.9%(55/108) and positively associated with tumor size, TNM stage, number of lymph node metastasis, vascular invasion, perineural invasion, Ki-67, P53 and distant metastasis (P < 0.05). There was no correlation between UBQLN1 expression and age, menostasis, pathological type, pathological grade, ER, PR, Her2/neu, genetic typing or lymphoplasmacytic invasion (P > 0.05). Non-parametric Spearman rank correlation analysis showed that there was a positive correlation between the expression of UBQLN1 and P53 (r=0.262, P=0.006). Univariate Kaplan-Meier analyses revealed there was negative correlation between the overexpression of UBQLN1 and survival rate (P < 0.05). Cox-regression analysis indicated that the overexpression of UBQLN1 was an independent prognostic factor for overall survival (OS) and disease free survival (DFS) of breast cancer patients.

Conclusion UBQLN1 is overexpressed in breast cancer samples and closely associated with various clinicopathological features and poor prognosis of breast cancer patients. It could be a novel molecular marker to evaluate the prognosis of breast cancer patients.