Tumour suppressor protein (p53), apoptosis inhibiting protein (Bcl-2) and proliferating cell nuclear antigen (PCNA) expressions in a rat pancreatic tumour model

Background: Previous studies have shown that, cultured rat pancreatic carcinoma cells, derived from azaserine-induced acinar tumours, yield tumours with a ductal phenotype. Materials and Methods: In order to find out the molecular characteristics of this tumour model, tumour suppressor protein (p53), apoptosis inhibiting protein (Bcl-2) and proliferating cell nuclear antigen (PCNA) expressions were analysed in rat pancreatic and subcutaneous tumours, as well as in normal rat pancreas. Results: Immunoreactivity for p53 protein was found in 86% of intrapancreatic tumours and in 100% of subcutaneous tumours. The average fraction of positive carcinoma cells was over 50%. Normal rat pancreas showed only slight positive or negative staining for p53. Bcl-2 did not show positive immunoreactivity in rat tumour samples. For PCNA all tumour samples showed positive staining. Also normal pancreas of 6-week-old animals were clearly positive, whereas the samples of the older animals were only slightly positive. Conclusion: Possible mutations in the p53 tumour suppressor gene and a strong expression of PCNA were shown in carcinoma cell line-induced rat pancreatic tumours. These features of the rat pancreatic tumour model resemble human pancreatic carcinoma and may favour the use of this model in pancreatic cancer studies.