Adenocarcinoma, Biomarkers, Tumor, Biopsy, Fine-Needle, Clusterin, Diagnosis, Differential, Epithelial Cells, GPI-Linked Proteins, Humans, Inhibitor of Apoptosis Proteins, Membrane Glycoproteins, Mesothelin, Microtubule-Associated Proteins, Mucin-4, Mucins, Neoplasm Proteins, Pancreatic Ducts, Pancreatic Neoplasms, Pancreatitis, Research Design, Survivin