Staining for p53 and Ki-67 increases the sensitivity of EUS-FNA to detect pancreatic malignancy

AIM:To investigate whether tumor marker staining can improve the sensitivity of endoscopic ultrasound-guided fine needle aspiration(EUS-FNA)to diagnose pancreatic malignancy. METHODS:Patients who underwent EUS-FNA were retrospectively identified.Each EUS-FNA specimen was evaluated by routine cytology and stained for tumor markers p53,Ki-67,carcinoembryonic antigen(CEA) and CA19-9.Sensitivity,specificity,positive and negative predictive values(PPV and NPV),and positive and negative likelihood ratios(PLR and NLR)were calculated in order to evaluate the performance of each test to detect malignancy. RESULTS:Sixty-one specimens had complete sets of stains,yielding 49 and 12 specimens from pancreatic adenocarcinomas and benign pancreatic lesions due to pancreatitis,respectively.Cytology alone had sensitivity and specificity of 41%and 100%to detect malignancy, respectively.In 46%of the specimens,routine cytology alone was deemed indeterminate.The addition of either p53 or Ki-67 increased the sensitivity to 51%and 53%,respectively,with perfect specificity,PPV and PLR (100%,100%and infinite).Both stains in combination increased the sensitivity to 57%.While additional staining with CEA and CA19-9 further increased the sensitivity to 86%,the specificity,PPV and PLR were significantly reduced(at minimum 42%,84%and 1,respectively).Markers in all combinations performed poorly as a negative test(NPV 26%to 47%,and NLR 0.27 and 0.70).CONCLUSION:Immunohistochemical staining for p53 and Ki-67 can improve the sensitivity of EUS-FNA to diagnose pancreatic adenocarcinoma.