The utility of S100P in eus fnas of pancreatic tumours – can it help in distinguishing benign from malignant lesions

Abstract

Pancreatic ductal adenocarcinoma is the most common malignant neoplasm of the pancreas. Endoscopic ultrasound fine needle aspiration (EUS FNA) is a rapid, safe, cost-effective way to establish an accurate diagnosis of pancreatic cancer. Due to overlapping cy-tological features between neoplastic and reactive ductal epithelium, a high rate of false positivity/negativity involved in this test, we have explored the utility of tumour markers as an adjunct to conventional procedures. S100P is a protein in the S100 family of calcium binding proteins. S100P expression has been found to increase during the progression from pancreatic intraepithelial neoplasia to invasive adenocarcinoma, but is absent in benign and reactive pancreatic epithelial cells. The diagnostic value of S100P on FNA biopsy specimens of the pancreas was evaluated. There were 300 cases of pancreatic FNAs in the department, of which 50 cases where cell blocks contained adequate material were utilised for this pilot study. Mixes of benign, suspicious and malignant cases were included. Unstained sections from the cell block were stained with S100P. The slides have been analysed based on intensity and percentage of staining. Nuclear or nuclear/cytoplasmic staining was regarded as positive. Cytoplasmic without nuclear staining was regarded as negative. The sensitivity and specificity were calculated.