BACKGROUND MicroRNAs (miRNAs) are RNA molecules that are involved in the regulation of many cellular processes, including those related to human cancers. The aim of this study was to determine, as a proof of principle, whether specific candidate miRNAs could be detected in fine-needle aspirate (FNA) biopsies of pancreatic ductal adenocarcinoma (PDAC) and could accurately differentiate malignant from benign pancreatic tissues. METHODS We used TaqMan® assays to quantify miRNA levels in FNA samples collected in RNARetain (n = 16) and compared the results with a training set consisting of frozen macrodissected pancreatic samples (n = 20). RESULTS Quantitative reverse-transcription PCR analysis confirmed that miRNA levels are affected in PDAC FNAs and correlate well with the changes observed in the training set of frozen pancreatic samples. Analysis of the amounts produced for a few specific miRNAs enabled identification of PDAC samples. The combination of miR-196a and miR-217 biomarkers further improved the ability to distinguish between healthy tissue, PDAC, and chronic pancreatitis in the training set (P = 8.2 × 10−10), as well as segregate PDAC FNA samples from other FNA samples (P = 1.1 × 10−5). Furthermore, we showed that miR-196a production is likely specific to PDAC cells and that its incidence paralleled the progression of PDAC. CONCLUSIONS To the best of our knowledge, this study is the first to evaluate the diagnostic potential of miRNAs in a clinical setting and has shown that miRNA analysis of pancreatic FNA biopsy samples can aid in the pathologic evaluation of suspicious cases and may provide a new strategy for improving the diagnosis of pancreatic diseases.

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The distinction between sarcomatoid carcinoma (SC) and bona fide sarcoma can be difficult using conventional immunohistochemical markers. Epithelial-mesenchymal transition (EMT) has been proposed as a histogenetic mechanism for the development of SC. Expression of selected markers of EMT (Twist and Slug) was compared with other markers of epithelial differentiation in SC and spindle cell sarcoma to determine the utility of these antigens in this differential diagnosis. Twenty-seven cases of SC (excluding those of gynecologic origin) were stained by immunohistochemistry for cytokeratins (AE1/AE3, 5D3, CK5/6, and 34betaE12), p63, claudin-1, claudin-7, epithelial cadherin, placental cadherin, epithelial cell adhesion molecule/epithelial-specific antigen, 14-3-3sigma, Twist, and Slug. A comparison group of 21 spindle or pleomorphic spindle cell sarcomas was also studied. Immunohistochemical stains were scored in a semiquantitative manner and subsequent exploratory analyses were performed using logistic regression and chi2 tests. Only cytokeratin AE1/AE3 specifically labeled SC in a statistically significant manner. Other epithelial-specific markers tested did not distinguish SC from sarcoma primarily owing to low sensitivity. However, when positive, immunostains such as CK5/6, membranous epithelial cadherin, and nuclear p63 may aid in the distinction of SC from sarcoma. EMT markers were expressed in most cases of both SC and sarcoma, and were not useful in making a differential diagnosis between these neoplasms.

Listeria monocytogenes infections have been described in patients with diverse types of malignancy, especially leukemia. We report the case of a 65-year-old man with previously untreated hairy cell leukemia characterized by CD5 positivity and trisomy 12 (3% of blood lymphocytes) who developed bacteremia due to L. monocytogenes serotype 1/2b. We summarize clinical features and treatment of this patient and five previously reported patients with hairy cell leukemia who also had L. monocytogenes infections. All six patients were men. Their mean age at infection diagnosis was 70 y. Three men had undergone splenectomy 4–11 y before they developed L. monocytogenes infection. The central nervous system was the primary site of infection in four men. Bacteremia alone occurred in two other men. At diagnosis of infection, one man was receiving antileukemia chemotherapy and another man was receiving treatment for Kaposi's sarcoma. Two other patients had other comorbid conditions. All six men recovered from their infections.