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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.