PANCREATIC CANCER STEM CELLS EXPRESSION ON ENDOSCOPIC ULTRASOUND FINE NEEDLE BIOPSY PANCREATIC DUCTAL ADENOCARCINOMA SAMPLES.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an intense fibrosis which enhances the growth of tumor cells and drives an epithelialmesenchymal transition. The consequence is the uncontrolled proliferation of cancer cells, including pancreatic cancer stem cells (PCSC), which can enhance the metastatic potential. Objective. The aim of this study is to assess the expression of pancreatic cancer stem cells, on pancreatic endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) specimens. Material and Methods. A total of 21 patients diagnosed with PDAC after EUS-FNB within the Research Center of Gastroenterology and Hepatology of Craiova, were included in the study, and the samples were sent for immunohistochemical assessment. Anti-Human CD 24 (policlonal, Abcam, ab 199140) and EpCAm (Epr 20532-225, Rb monoclonal, Abcam, ab 223582) were used. Results. All cases were positive for CD24 and EpCAM. In NOS ductal adenocarcinomas, CD24 immunomarking was heterogeneous, with variable intensity and a variable number of positive cells within the same case. Well and moderately differentiated adenocarcinomas that formed tubular or papillary structures showed a higher intensity CD24 expression compared to poorly differentiated or undifferentiated adenocarcinomas. EpCam showed a stronger immunolabeling intensity in the analyzed samples. PDAC EpCam expression was of moderate and high intensity and with a heterogeneous appearance in NOS G1 adenocarcinomas, but the intensity of the immunomarking tended to decrease with increasing histological grade. Conclusions. EUS-FNB PCSC immunohistochemistry is feasible. At the subcellular level, the basolateral membranous and cytoplasmic staining of EpCam in PDAC could be correlated with tumor invasion and possibly with the unfavorable evolution of this type of carcinoma, while CD24 frequently presents an apical immunostaining pattern and could suggest the presence of an epithelial-type phenotype of tumor cells, with a lower potential for invasiveness and metastasis. [ABSTRACT FROM AUTHOR]