Abstract: Objective   To analyze the expression of bromodomaincontaining protein 4 (BRD4) in colorectal cancer (CRC) tissue,and to explore its relationship with clinicopathological characteristics and prognosis of patients.  Methods   CRC patients admitted to our hospital from November 2014 to May 2017 were collected,and CRC tissue and paracancerous tissue were excised from the patients during radical resection.Real-time fluorescence quantitative PCR (qRT-PCR) and immunohistochemistry were used to measure the expression of BRD4 mRNA and BRD4 protein in CRC tissue and paracancerous tissue,respectively;Kaplan-Meier survival curve was used to analyze the relationship between BRD4 expression and patient prognosis;COX regression was applied to analyze the risk factors affecting the prognosis of CRC patients.  Results   Compared with the adjacent tissues,the expression level of BRD4 mRNA and the positive expression rate of BRD4 protein in CRC tissues were obviously increased (P<0.05).The expression level of BRD4 mRNA was correlated with regional lymph node metastasis (N) and distant metastasis (M) in CRC patients (P<0.05),the expression of BRD4 protein was correlated with the degree of tissue differentiation,N and M in CRC patients (P<0.05).Kaplan-Meier analysis showed that the 5-year progression-free survival rates of patients with high BRD4 mRNA expression and BRD4 protein positive expression were obviously lower than those of patients with low BRD4 mRNA expression (P＜0.05) and BRD4 protein negative expression (P＜0.05).The 5-year cumulative survival rates of patients with high expression of BRD4 mRNA and positive expression of BRD4 protein were significantly lower than those with low expression of BRD4 mRNA (P＜0.05) and negative expression of BRD4 protein (24/32) (P＜0.05) patients.Multivariate COX regression analysis showed that N₁-N₂,M₁,the high expression of BRD4 mRNA and the positive expression of BRD4 were risk factors affecting the prognosis of CRC patients (P<0.05).  Conclusion   BRD4 is highly expressed in CRC tissue,there is a certain correlation with N,M and prognosis of patients,and it can be used as one of the indicators for the prognosis of CRC patients.

Key words: colorectal cancer, bromodomain-containing protein 4, clinicopathological features, prognosis