Mucin expression pattern in pancreatic diseases: findings from EUS-guided fine-needle aspiration biopsies.

OBJECTIVES: Alterations in mucin (MUC) glycosylation and expression have been described in cancer. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) can provide material for molecular biology analysis. This study assessed the feasibility of evaluating MUC expression from material obtained by EUS-FNA and studied the profile of MUC expression in benign and malignant pancreatic lesions. METHODS: A total of 90 patients with solid or cystic pancreatic lesions underwent FNA. The aspirated material was used for cytological analysis and RNA extraction to assess the expression pattern of MUCs by reverse transcription-PCR with primers specific for the MUC1, MUC2, MUC3, MUC4, MUC5A, MUC5B, MUC6, and MUC7 genes. RESULTS: RNA extraction was successful in 81% of the biopsies. The prevalences of MUC1, MUC2, MUC4, and MUC7 in ductal adenocarcinoma were 57.7, 51.4, 18.9, and 73.0%, respectively. Fifty percent of benign lesions and neuroendocrine tumors (NETs), and 63% of intraductal papillary mucinous neoplasms (IPMNs) were positive for MUC1. Twenty-five percent of benign lesions, 86% of NETs, and 47% of IPMNs were positive for MUC2. Of NETs, 50% were positive for MUC1, and 14% were positive for MUC7. None of the benign lesions or NETs expressed MUC4. MUC7 expression was highly significant for adenocarcinoma (P=0.007) and borderline for IPMN (P=0.05). MUC7 was expressed in 37.5% of chronic pancreatitis cases. CONCLUSIONS: RNA can be extracted from samples obtained under EUS-FNA. MUC7 could serve as a potential biological marker to identify malignant lesions, especially pancreatic adenocarcinoma.