Expression and prognostic significance of serum response factor in cholangiocarcinoma

Background: Serum response factor (SRF) is a transcriptional factor that plays an important role in cell growth and differentiation for several types of cells. The expression of SRF in cholangiocarcinoma (CC) and its potential role has not been examined. The aim of this study was to determine the relationship between the expression of SRF in CC and the clinicopathological parameters, as well as patient survival. Methods: We analyzed the expression of SRF in 84 surgically resected cases of CC (33 cases of intrahepatic CC [ICC] and 51 cases of extrahepatic CC [ECC]) by using immunohistochemistry. Results: The positive expression of SRF was detected in 48.8% of the cases of CC (42.4% in ICC, 52.9% in ECC). SRF was predominantly expressed in the CC cells with intense labeling in the nucleus. A SRF expression was significantly associated with the cell proliferation rate (Ki-67 labeling index, p=0.046) and poor patient survival (p=0.002). The tumor differentiation (p=0.038), the T category (p<0.001), lymph node and distant metastasis (p<0.001, p=0.009) and nerve and vessel invasion (p=0.010, p=0.012) were also found to be significantly associated with a poor CC prognosis. Conclusions: These results suggest that the SRF may play a role in the tumor cell proliferation of CC, and its expression in tumor cells can provide additional prognostic information.