Overexpression of c-met in the early stage of pancreatic carcinogenesis; altered expression is not sufficient for progression from chronic pancreatitis to pancreatic cancer

Figure 1 PCR products were analyzed with an Agilent Bioanalyzer 2001. A single 149-bp band was observed for c-met primer pairs (left panel). A single 138-bp band was observed for β-actin primer pairs (right panel). Each primer pair used in the present study produced a single melting peak on real-time RT-PCR and a single prominent band of the expected size on microchip electrophoresis.

Figure 2 We performed quantitative real-time RT-PCR to quantify c-met expression in pancreatic cancer tissues (n = 11), normal pancreatic tissues (n = 20), and chronic pancreatitis tissues (n = 15). c-met was overexpressed in pancreatic cancer tissues in comparison to expression in normal pancreatic (P = 0.0017) and chronic pancreatitis tissues (P = 0.0047). Levels of c-met did not differ between normal pancreatic and chronic pancreatitis tissues (P = 0.4433).

Figure 3 c-met expression in pancreatic cancer cell lines and primary pancreatic fibroblasts. The median value of c-met expression from pancreatic cancer cell lines was 0.742. In contrast, the median value of c-met expression in 4 primary cultures of pancreatic fibroblasts (Panc-f1, Panc-f2, Panc-f3, and Panc-f4) was 0.023.

Figure 4 Quantitative analysis of c-met mRNA levels in microdissected pancreatic cancer cells (n = 13), pancreatitis-affected epithelial cells (n = 11), and normal pancreatic ductal epithelial cells (n = 12). c-met levels in pancreatic cancer cells (median, 1.208) were 2.21-fold higher than those in normal ductal epithelial cells (median, 0.546; P = 0.0011). c-met levels in pancreatitis-affected epithelial cells (median, 1.211) were 2.22-fold higher than those in normal ductal epithelial cells (median, 0.546; P = 0.005). c-met levels in microdissected normal ductal epithelial cells were the lowest with a median value of 0.546. Interestingly, pancreatitis-affected epithelial cells expressed levels of c-met that approached those in pancreatic cancer cells.