Over-Expression of C-Met Contributes to the Progression of Pancreatic Cancer

Background: Pancreatic cancer is one of the most lethal malignancies with median overall survival of merely 6 months. The lethality of pancreatic cancer is largely due to aggressive localized invasion and metastasis at an early stage. Previous studies suggested c-met was over-expressed in the early stage of pancreatic carcinogenesis. However, little is known about its expression in pancreatic cancer (PC) tissues and its relationship to various clinicopathological parameters. In this study, we aimed to explore the expression of c-met and its correlation with clinicopathological features in PC. Methods: 108 cases of surgically resected PC specimens and 12 normal pancreas (NP) specimens were collected from the First Affiliated Hospital of Xi'an Jiaotong University from March 2008 to June 2012. The immunohistochemical method was carried out to detect c-met expression in PC and NP. The correlations of c-met protein expressions with clinical pathologic features of PC were also analyzed in our research. Results: The positive rate of c-met expression in PC tissues (67.6%, 73/108) was significantly higher than that in NP tissues (16.7%, 2/12). There was no or very low level of c-met expression in most NP cases, in contrast, most of the PC tissues showed moderate to high c-met staining intensity. In PC with lymph node metastasis, the positive rate of c-met (83.8%, 62/74) was significantly higher than that in the group without lymph node metastasis (32.4%, 11/34), (P < 0.05). A significant increasing expression of c-met was detected in PC tissues with perineural invasion (PNI) (72.6%, 68/95) compared with in PC tissues without PNI (38.5%, 5/13), (P < 0.05). In addition, the expression of c-met protein was closely associated with TNM stage. However, c-met expression was not related to age, sex, tumor location, and tumor size. Conclusion: Our result showed that the c-met expression was increased in the PC tissues compared with NP tissues. These data also suggested that the positive rate of c-met was closely correlated with the high incidence rate of lymph node metastasis and PNI in the course of PC progression.