We have encountered cases of unusual intraductal pancreatic neoplasms with predominant tubulopapillary growth. We collected data on 10 similar cases of "intraductal tubulopapillary neoplasms (ITPNs)" and analyzed their clinicopathologic and molecular features. Tumor specimens were obtained from 5 men and 5 women with a mean age of 58 years. ITPNs were solid and nodular tumors obstructing dilated pancreatic ducts and did not contain any visible mucin. The tumor cells formed tubulopapillae and contained little cytoplasmic mucin. The tumors exhibited uniform high-grade atypia. Necrotic foci were frequently observed, and invasion was observed in some cases. The ITPNs were immunohistochemically positive for cytokeratin 7 and/or cytokeratin 19 and negative for trypsin, MUC2, MUC5AC, and fascin. Molecular studies revealed abnormal expressions of TP53 and SMAD4 in 1 case, but aberrant expression of beta-catenin was not observed. No mutations in KRAS and BRAF were observed in the 8 cases that were examined. Eight patients are alive without recurrence, 1 patient died of liver metastases, and 1 patient is alive but had a recurrence and underwent additional pancreatectomy. The mitotic count and Ki-67 labeling index were significantly associated with invasion. All the features of ITPN were distinct from those of other known intraductal pancreatic neoplasms, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and the intraductal variant of acinar cell carcinoma. Intraductal tubular carcinomas showed several features that were similar to those of ITPN, except for the tubulopapillary growth pattern. In conclusion, ITPNs can be considered to represent a new disease entity encompassing intraductal tubular carcinoma as a morphologic variant.
The long non-coding RNA HOTAIR has been reported to be a poor prognostic biomarker in a variety of malignant tumors. However, little is known about the association of HOTAIR with gastric cancer. We examined the expression of HOTAIR in 68 gastric cancer samples using quantitative real-time RT-PCR and analyzed its correlation with the clinical parameters. The functional role of HOTAIR was examined by generating human gastric cancer cell lines with increased or suppressed HOTAIR expression. The anchorage -independent growth was assessed by soft agar assay. The increased or suppressed HOTAIR expressing gastric cancer cells were injected into the tail vein or peritoneal cavity of immunodeficient mice to examine the effect of this molecule on metastasis and peritoneal dissemination. The expression of HOTAIR was significantly higher in cancer lesions than in adjacent non-cancerous tissues in human gastric cancers. In the diffuse type of gastric cancer, the High-HOTAIR group (HOTAIR/GAPDH > 1) showed significantly more venous invasion, frequent lymph node metastases and a lower overall survival rate compared to the Low-HOTAIR group (HOTAIR/GAPDH < 1). Colony formation on the soft agar was enhanced in a HOTAIR-dependent manner. HOTAIR-expressing MKN74 formed more liver metastasis compared to control when they were injected into the tail vein of mice. In addition, reduced expression of HOTAIR in KATO III suppressed peritoneal dissemination. These results suggest that HOTAIR plays a pivotal role in the development of gastric cancer.
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