Low expression of B-Cell-Associated protein 31 is associated with unfavorable prognosis in human colorectal cancer.

Colorectal cancer (CRC) is one of the most common cancers worldwide. B cell-associated protein 31 (BAP31) was shown to participate in the apoptosis, and to be an immunotherapy target and a, prognostic factor for cancer, but its role in CRC has not been elucidated. In this study, we examined the expression of BAP31 in CRC to evaluate its prognostic values. We investigated the BAP31 expression level in 142 tissues (108 CRC and 17 paired human adjacent normal mucosa, and 17 liver metastatic CRC tissues) from 108 patients, using tissue microarray-based immunohistochemistry. We further investigated the association between BAP31 expression and overall survival (OS) and disease-free survival (DFS) in 77 CRC patients using Kaplan-Meier analysis. Univariate and multivariate Cox regression analyses were applied to evaluate the potential prognostic value of BAP31 in CRC patients. BAP31 expression level was significantly increased in CRC tissues (p = 0.0014) and liver metastatic CRC tissues (p < 0.0001) compared with corresponding adjacent normal mucosa. BAP31 expression was also significantly increased in liver metastatic CRC tissues compared with corresponding primary CRC tissues (p = 0.0116). Kaplan-Meier analyses showed that CRC patients with low BAP31 expression had significantly lower survival rate (p = 0.001) and lower disease-free survival rate (P = 0.009). Furthermore, multivariate Cox analysis showed that BAP31 was an independent prognostic factor for OS (hazard ratio = 0.410, 95% confidence interval = 0.195-0.862, p = 0.019). CONCLUSIONS: Our study demonstrated that BAP31 is a potential prognostic marker for CRC patients after surgery.