AIM:To evaluate p53 protein overexpression and to measureserum CA19,9 concentrations in cytological diagnosis ofpatients with suspected pancreatic cancer,METHODS:24 patients with suspected pancreatic cancerdue to chronic pancreatitis,had a pancreatic mass determinedby imaging methods.The serum CA19.9 concentration wasmeasured by solid phase radioimmunoassay.On laparotomy,puncture biopsy was performed,and specimens weredivided into two parts for cytological diagnosis and detectionof p53 protein.RESULTS:Cytology offered a sensitivity of 0.63,a specificityof 1.00,and an accuracy of 0.63.p53 protein analysis offereda sensitivity of 0.44,a specificity of 1.00,and an accuracy of0.73.CA19.9 offered a sensitivity of 0.44,a specificity of0.80,and an accuracy of 0.67.The combined cytology andp53 protein analysis showed a sensitivity of 0.78,a specificityof 1.00,and an accuracy of 0.92.Cytology and CA19.9showed a sensitivity of 0.67,a specificity of 0.80,an accuracyof 0.67.combined cytology and p53 protein analysis andCA19.9 showed a sensitivity of 0.78,a specificity of 0.80,and an accuracy of 0.79.CONCLUSION: Superior to any single test, the combined approach is helpful for the differential diagnosis of pancreatic cancer complicated with chronic pancreatitis.The combined cytology and p53 protein analysis offers the best diagnostic efficacy. AIM: To evaluate p53 protein overexpression and to measureserum CA19, 9 concentrations in cytological diagnosis of patients with suspected pancreatic cancer, METHODS: 24 patients with suspected pancreatic cancer with chronic pancreatitis, had a pancreatic mass determined by imaging methods. The serum CA 19.9 concentration wasmeasured by solid phase radioimmunoassay. On laparotomy, puncture biopsy was performed, and specimens weredivided into two parts for cytological diagnosis and detection of p53 protein. RESULTS: Cytology offered a sensitivity of 0.63, a specificity of 1.00, and an accuracy of 0.63.p53 protein analysis offereda sensitivity of 0.44, a specificity of 1.00, and an accuracy of 0.73, CA 19.9 offered a sensitivity of 0.44, a specificity of 0.80, and an accuracy of 0.67. The combined cytology and p53 protein analysis showed a sensitivity of 0.78, a specificity of 1.00, and an accuracy of 0.92. Cytology and CA 19.9 showed a sensitivity of 0.67, a specificity of 0.80, an accuracy of 0.67.com bound cytology and p 53 protein analysis and CA19.9 showed a sensitivity of 0.78, a specificity of 0.80, and an accuracy of 0.79. CONCLUSION: Superior to any single test, the combined approach is helpful for the differential diagnosis of pancreatic cancer complicated with chronic pancreatitis. Combined cytology and p53 protein analysis offers the best diagnostic efficacy.