Although recent studies revealed that adipose tissue accelerates pancreatic tumor progression with excessive extracellular matrix, key players for desmoplasia in the adipose microenvironment remains unknown. Here, we investigated the roles of adipose tissue-derived stromal cells (ASCs) in desmoplastic lesions and tumor progression by in vitro and in vivo experiments. In a three-dimensional (3-D) organotypic fat invasion model using visceral fat from CAG-EGFP mice, GFP-positive fibroblastic cells infiltrated toward cancer cells. When tumor cells were inoculated into transplanted visceral fat pads in vivo, tumor weights and stromal components were enhanced compared to subcutaneous and orthotopic tumor cells inoculated without fat pads. Expression of αSMA in established human ASCs was lower compared to cancer associated fibroblasts, and the 3-D collagen matrices produced by ASCs cultured in cancer cell-conditioned medium changed from loose to dense structures that affected the motility of cancer cells. Microarray analyses revealed upregulation of S100A4 in ASCs, while S100A4-positive stromal cells were observed at extrapancreatic invasion sites of human pancreatic cancer. The present findings indicate that ASCs are recruited to extrapancreatic invasion sites and produce dense collagen matrices that lead to enhanced tumor progression. Both inhibition of ASCs recruitment and activation could lead to a novel antistromal therapy.

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BackgroundParacecal hernias, also known as pericecal hernias, are an exceptionally rare type of internal hernia. We report a unique case of paracecal hernia due to membranous adhesion of the omentum to the right paracolic gutter.Case presentationAn 86-year-old female was admitted to our hospital with vomiting and abdominal pain. Laboratory findings showed a slightly elevated C-reactive protein level. Computed tomography scan showed dilated loops of the small intestine in the right paracolic gutter with medial displacement of the cecum and ascending colon. Internal hernia around the cecum due to postoperative adhesion after appendectomy was suspected, and she underwent emergency laparotomy. Intraoperative findings revealed the adhesion between the omentum and right paracolic gutter forming a cavity with the small intestine incarcerated. No abnormal adhesion in the ileocecal region was seen. We transected the omental adhesion from the orifice to the far end of the cavity near the hepatic flexure of the colon to release strangulation and to prevent recurrence. The patient was discharged on postoperative day 14 without complications.ConclusionsParacecal hernias have a type of membranous adhesion of the omentum to the right paracolic gutter. Surgeons should be aware of this paracecal hernia type, when they encounter the internal hernia.