Deregulated Mucin Carbohydrate Antigens Tn and Sialosyl-Tn: Potential Utility in Fine Needle Aspiration Specimens of Pancreas
Kun Jiang, Cynthia Cohen, Sean R Stowell, Richard D Cummings, Momin T Siddiqui. Emory University School of Medicine, Atlanta, GA
Background: Abnormal levels of glycan antigen Tn and sialylated structure STn have been implicated in the initiation and progression of a variety of carcinomas. However, their impact on pancreatic cancers remains poorly understood. In addition, deregulated protein glycosylation has been well recognized as a common feature of malignancies, but the potential diagnostic utility of Tn and STn in pathologic diagnosis, especially in fine needle aspiration (FNA) cell blocks (CB), has not been clearly addressed. Hence, this study evaluated and compared the expression of Tn and STn in FNAs from different types of neoplasm and non-tumor tissues of pancreas, in an attempt to determine their potential diagnostic applicability.
Design: Tn and STn were evaluated immunohistochemically in 46 pancreatic ductal adenocarcinoma (PDAC), 5 neuroendocrine tumors, and 8 non-neoplastic pancreatic FNA CB. Membranous labeling and granular cytoplasmic staining for Tn or STn (3+ and >10% cells) was considered positive. The data were analyzed by statistical analysis.
Results: Forty-three and forty-one of 46 PDAC CB displayed positive staining for Tn (sensitivity 93.48%; specificity 87.50%) and STn (sensitivity 89.13%; specificity 87.50%), respectively; adjacent non-neoplastic tissue showed either negativity or minimal levels of Tn and STn (P<0.001). Only 12.5% (1/8) of non-tumor specimens showed minimal to moderate Tn or STn expression (focally 2+). Furthermore, no positivity was detected in pancreatic neuroendocrine tumors for either Tn or STn.
|Pancreatic FNAs (number)||Tn +++||STn +++|
|PDAC (46)||43 (93.48%)||41 (89.13%)|
|Neuroendocrine tumors (5)||0 (0%)||0 (0%)|
|Non-tumor (8)||1 (12.5%)||1 (12.5%)|