Expression of the tumor suppressor gene maspin and its significance in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND: Maspin is a member of the serpin family of protease inhibitors and is thought to inhibit carcinoma invasion, metastasis, and angiogenesis and induce apoptosis. We examined maspin expression immunohistochemically and assessed its significance in intraductal papillary mucinous neoplasm (IPMN) of the pancreas. METHODS: We examined 39 surgically resected specimens of IPMN that included 17 adenomas (IPMAs), 5 borderline tumors (IPMBs), 4 non-invasive carcinomas (non-invasive IPMCs), and 13 invasive carcinomas (invasive IPMCs). Immunostaining was performed according to the EnVision ChemMate method. The degree of maspin expression was scored and assessed according to the percentage and staining intensity of positive cells. RESULTS: Maspin expression was minimal in normal pancreatic duct epithelium, whereas in IPMNs, maspin was expressed in neoplasms of all stages. Maspin expression increased with increasing grade from IPMAs, IPMBs, to non-invasive IPMCs but decreased significantly in invasive IPMCs. No specific association between maspin expression and mucin type was found. Analysis of maspin expression with respect to clinicopathologic factors in cases of invasive IPMC revealed a greater extent of invasion in cases of low maspin expression and significantly fewer apoptotic cells in the tumor.CONCLUSIONS: Maspin was expressed at high levels in IPMNs at various stages from adenoma to invasive carcinoma, and our results suggest that maspin may be involved in the occurrence and progression of IPMN. In addition, our data suggest that the apoptosis-inducing action of maspin suppresses invasion and progression of IPMN.

Gastric-and intestinal-type marker expression in invasive ductal adenocarcinoma of the pancreas

BACKGROUND:Although invasive ductal adenocarcinoma of the pancreas(PDAC) manifests as a relatively uniform histomorphological feature of the pancreatobiliary type,it may be complicated by metaplastic changes and heterogeneous gastric and intestinal elements.This study aimed to investigate the complication rate and clinicopathological significance of such heterogeneous elements.METHODS:Fifty-nine patients who underwent resection of PDAC were examined in this study.Immunohistochemically,tumors showing high expression(>25%) of the intestinal-type(INT) marker CDX2 were classified as PDAC with INT.Those with high expression(>25%) of the gastric-type(GAS) marker MUC5AC were classified as PDAC with GAS,while those with high expression of both markers were classified as PDAC with INT/GAS.These patients were compared with those with PDAC of the negative group in which neither markers was highly expressed to examine their clinicopathological significance.RESULTS:In the 59 patients,31(52.5%) showed high CDX2 or MUC5AC expression.Twenty-eight patients(47.5%) belonged to a negative group,11(18.6%) to a PDAC with INT group,15(25.4%) to a PDAC with GAS group,and 5(8.5%) to a PDAC with INT/GAS group.No significant differences were observed for age,gender,size,localization,T classification,or prognosis among the four groups.Although the PDAC with GAS group had well differentiated types significantly more than the other groups,the rate of lymph node metastasis in this group was significantly higher(PDAC with GAS:73%;other groups:36%).CONCLUSION:Complications with heterogeneous elements are not uncommon in PDAC,and this should be considered during the diagnosis and treatment of PDAC along with histogenesis of the disease.