The role of S100P and IMP3 in the cytologic diagnosis of pancreatic adenocarcinoma.

Purpose: The aim of this study was to assess the role of the two markers, S100P and IMP3, in differentiating between pancreatic ductal adenocarcinoma (PDA) and non-neoplastic pancreatic tissue in (fine needle aspiration cytology) FNAC.

Patients And Methods: This is a retrospective study that included 72 cases presented with pancreatic mass, where endoscopic guided FNAC was taken from pancreatic lesions. The final histopathologic diagnosis was considered the gold standard. Cell blocks were stained with anti S100P, and IMP3. Nuclear immunoreactivity with or without cytoplasmic staining for the first marker, and cytoplasmic staining for the second marker was considered specific. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and total accuracy of the two markers, as well as the combined accuracy of both markers were calculated.

Results: S100P achieved 96.4% sensitivity, 93.3% specificity, 98.2% PPV, 87.5% NPV and 95.8% total accuracy, while IMP3 achieved 91.2% sensitivity, 86.7% specificity, 96.2% PPV, 72.2% NPV and 90.3% total accuracy for PDA. Both markers showed a total combined accuracy of 89%. S100P showed strong and diffuse staining pattern in most of cases, while the staining pattern for IMP3 was moderate and focal in most of cases.

Conclusion: Both markers were sensitive and specific for diagnosis of PDA. The staining pattern for S100P was easier to evaluate than IMP3.