Perivascular epithelial cell tumor (PEComa) of the pancreas: a case report and review of previous literatures.

Perivascular epithelial cell tumors (PEComas), firstly described by Bonetti in 1992, are a family of mesenchymal tumor composed of perivascular epithelioid cells having epithelioid or spindle morphology and exhibiting melanocytic and myogenic immunoreactivities. We herein described a 61-year-old woman who presented with epigastric pain. Preoperative imaging studies showed that 7-cm-sized mass was located in pancreatic head and body, and pancreaticoduodenectomy was performed. Histological findings showed that the tumor was composed of clear epithelioid cells with abundant glycogen granules, which grew in a nested and alveolar pattern around blood vessels. The tumor cells showed immunoreactivities for HMB-45 but did not express epithelial or endocrine markers. These histological features indicated those of PEComa. This report underlines that we should recognize PEComa as a preoperative differential diagnosis of pancreatic tumors.

Insulin-like growth factor II messenger RNA-binding protein-3 is a valuable diagnostic and prognostic marker of intraductal papillary mucinous neoplasm.

Recently, various studies have shown that insulin-like growth factor II messenger RNA-binding protein-3 (IMP3) is a useful diagnostic marker for malignant lesions and a prognostic marker for poor survival in several kinds of tumors. However, the value of IMP3 as a diagnostic and prognostic marker in intraductal papillary mucinous neoplasm (IPMN) of pancreas has been unclear until now. In this study, we examined IMP3 immunohistochemical expression in 190 resection samples and 15 biopsy samples of IPMN and analyzed the value of IMP3 as a diagnostic and prognostic marker. IMP3 expression was recognized in 71.8% (28/39) of IPMNs with high-grade dysplasia and in 81.3% (26/32) of IPMNs with an associated invasive carcinoma (IPMN-IC), but it was not found in any IPMNs with low-grade dysplasia or in IPMNs with intermediate dysplasia. IMP3 expression was significantly higher in cancerous lesions (IPMN with high-grade dysplasia and IPMN-IC) than in noncancerous lesions (IPMN with low-grade dysplasia and IPMN with intermediate-grade dysplasia), with a sensitivity of 76.1% and a specificity of 100% (P < .001). We also identified a significant difference in IMP3 expression between cancerous lesions and noncancerous lesions in biopsy specimens (P = .027). In IPMN-IC, disease-specific survival was significantly shorter in the high-expression group (>50% tumor staining) than in the low-expression group (≤50% tumor staining; P = .0069). In conclusion, our findings show that IMP3 is a useful diagnostic marker for distinguishing between noncancerous and cancerous lesions and is a valuable prognostic biomarker in IPMN.

Differential ezrin and phosphorylated ezrin expression profiles between pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and invasive ductal carcinoma of the pancreas.

Intraductal papillary mucinous neoplasms (IPMNs) and pancreatic intraepithelial neoplasia (PanINs) are important premalignant lesions of pancreatic cancer. Ezrin is a member of the ezrin, radixin, and moesin protein family and acts as a cross-linker between the plasma membrane and the actin cytoskeleton. We investigated the roles of ezrin during carcinogenesis in IPMN and invasive ductal carcinoma and examined whether ezrin was a prognostic factor. We examined ezrin and phosphorylated ezrin (p-ezrin) expression in 131 IPMNs, 47 PanINs, and 59 invasive ductal carcinomas by immunohistochemical staining. Ezrin and p-ezrin (tyr354) expressions were significantly higher in IPMN with an associated invasive carcinoma, compared with those in IPMN with high-grade dysplasia (P = .03 and P = .0007, respectively). In all grades of PanINs, ezrin and p-ezrin (tyr353) were highly expressed. In patients with invasive ductal carcinoma, the presence of PanIN-2 or PanIN-3 was significantly correlated with positive ezrin and p-ezrin (tyr353) expression of the invasive ductal carcinoma component (P = .01 and P = .0004). The negative p-ezrin (tyr353) expression group of invasive ductal carcinoma showed a significantly worse prognosis than did the positive p-ezrin (tyr353) expression group by survival analysis (P = .04) and was a statistically significant adverse prognostic factor by both univariate and multivariate analyses (P = .048 and P = .015). Ezrin phosphorylation sites differ between the developments of IPMN and PanIN. Although p-ezrin (tyr354) expression in IPMNs is associated with tumor invasion, p-ezrin (tyr353) expression in invasive ductal carcinoma plays an important role not in tumor invasion and metastasis but in the early development of PanINs.

Liver-intestine cadherin expression is associated with intestinal differentiation and carcinogenesis in intraductal papillary mucinous neoplasm.

OBJECTIVES: Intraductal papillary mucinous neoplasms (IPMN) are classified into four phenotypes according to the WHO classification. Recently, intestinal-type IPMN has been suggested to grow with a distinct carcinogenetic pathway. Like mucin 2, oligomeric mucus/gel forming (MUC2) and caudal-related homeobox 2 (CDX2), liver-intestine cadherin (LI cadherin) is an intestine-specific marker. We aimed to investigate the roles of LI cadherin expression in IPMN. METHODS: We examined LI cadherin expression in 135 cases of IPMN by immunohistochemical staining and the quantitative real-time reverse-transcription polymerase chain reaction. RESULTS: LI cadherin protein and mRNA levels were significantly higher in intestinal-type IPMN than in nonintestinal-type IPMN (protein level, p < 0.001; mRNA level, p = 0.0312). A positive correlation was found between protein and mRNA of LI cadherin (p = 0.0037). The positivity rates of LI cadherin expression were significantly higher in CDX2-positive cases than in CDX2-negative cases (p < 0.001). In 41 intestinal-type IPMNs, LI cadherin-positive rates tended to increase gradually, from IPMN with low-grade dysplasia (IPMN-L) to IPMN with an associated invasive carcinoma (IPMN-IC) [IPMN-L vs. IPMN with high-grade dysplasia (IPMN-H); p = 0.0357, IPMN-L vs. IPMN-IC; p = 0.0230] and positively correlated with the Ki-67 labeling index (p = 0.0408), whereas this tendency was not recognized in nonintestinal-type IPMNs. CONCLUSIONS: LI cadherin is associated with an intestinal phenotype and an 'intestinal pathway' of carcinogenesis in IPMN.

Senescence in intraductal papillary mucinous neoplasm of the pancreas.

Intraductal papillary mucinous neoplasm of the pancreas is attracting attention as a precursor lesion of the invasive ductal adenocarcinoma, whereas it has been reported that some intraductal papillary mucinous neoplasms do not display progression to malignancy and remain almost unchanged in size and morphology. Recent studies have reported that oncogene-induced senescence has been observed in neoplasms, especially in premalignant lesions, and that it can play an important role in preventing malignant progression. To clarify the presence of senescence in intraductal papillary mucinous neoplasms, we analyzed the expression of several markers of senescence. The intraductal papillary mucinous neoplasms evaluated in this study were classified into 4 groups according to the degree of dysplasia. Senescence-associated ß-galactosidase activity and senescence-associated heterochromatin foci formation were investigated in 33 cases of intraductal papillary mucinous neoplasms and 6 normal controls. Immunohistochemical analysis of p16(INK4a) and p15(INK4b) was performed in 158 cases of intraductal papillary mucinous neoplasms and 10 normal controls. In the normal controls, neither senescence-associated ß-galactosidase activity nor senescence-associated heterochromatin foci formation was observed. Most of the normal epithelia were negative for either p16(INK4a) or p15(INK4b). For all 4 markers, the percentages of positive cases reached a peak in intraductal papillary mucinous neoplasm with low-grade dysplasia and showed significant decreasing trends in the transition from intraductal papillary mucinous neoplasm with low-grade dysplasia to intraductal papillary mucinous neoplasm with an associated invasive carcinoma. Our results indicate that senescence is induced in the early stage of intraductal papillary mucinous neoplasm and gradually attenuated according to the progression. It is suggested that senescence plays a role in preventing malignant progression of intraductal papillary mucinous neoplasm.

High EGFR mRNA expression is a prognostic factor for reduced survival in pancreatic cancer after gemcitabine-based adjuvant chemotherapy.

Pancreatic ductal adenocarcinoma (PDAC) still presents a major therapeutic challenge and a phase III clinical trial has revealed that the combination of gemcitabine and a human epidermal growth factor receptor type I (HER1/EGFR) targeting agent presented a significant benefit compared to treatment with gemcitabine alone. The aim of this study was to investigate EGFR mRNA expression in resected PDAC tissues and its correlation with patient prognosis. We obtained formalin-fixed paraffin-embedded (FFPE) tissue samples from 88 patients with PDAC who underwent pancreatectomy, and measured EGFR mRNA levels by quantitative real-time reverse transcription-polymerase chain reaction. The high-level EGFR group had significantly shorter disease-free-survival (p=0.029) and overall-survival (p=0.014) as shown by univariate analyses, although these did not reach statistical significance, as shown by multivariate analyses. However, we found that high EGFR expression was an independent prognostic factor in patients receiving gemcitabine-based adjuvant chemotherapy (p=0.023). Furthermore, we measured EGFR mRNA levels in 20 endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytological specimens. Altered EGFR levels were distinguishable in microdissected neoplastic cells from EUS-FNA cytological specimens compared to those in whole cell pellets. In conclusion, quantitative analysis of EGFR mRNA expression using FFPE tissue samples and microdissected neoplastic cells from EUS-FNA cytological specimens could be useful in predicting prognosis and sensitivity to gemcitabine in PDAC patients.

Adenocarcinoma involving the whole pancreas with multiple pancreatic masses.

A 77-year-old man was referred to our hospital for further investigation of pancreatic masses. Imaging studies revealed hypovascular masses in the pancreatic head and body. Total pancreatectomy was performed under the diagnosis of double primary pancreatic carcinomas. Macroscopic examination revealed 3 nodules: one each in the pancreatic head, body, and tail. Microscopically, all 3 lesions showed similar carcinoma cells, which communicated with each other via the intraductal component, indicating a single large tumor. Incidentally, we also identified an adenocarcinoma of the common bile duct (CBD). The final diagnosis was synchronous double cancer involving the whole pancreas and the CBD.

Pdcd4 expression in intraductal papillary mucinous neoplasm of the pancreas: its association with tumor progression and proliferation.

Intraductal papillary mucinous neoplasm is characterized by cystically dilated main and/or branch pancreatic duct with mucus. According to the degree of atypia, intraductal papillary mucinous neoplasm is classified into 3 groups: adenoma, borderline, and carcinoma. Furthermore, intraductal papillary mucinous neoplasm is considered to progress through an adenoma-carcinoma sequence like colorectal carcinoma. Programmed cell death 4 is a recently identified tumor suppressor that was found to inhibit translation. Programmed cell death 4 has been reported to inhibit tumorigenesis, tumor progression, proliferation, invasion, and metastasis in several human malignancies. We examined 108 cases of intraductal papillary mucinous neoplasm by immunohistochemistry and revealed that programmed cell death 4 expression was recognized in both the nucleus and cytoplasm in intraductal papillary mucinous neoplasm. The positive rate of programmed cell death 4 was 79%, 43%, and 10% in adenoma, borderline, and carcinoma, respectively. The positive rate of programmed cell death 4 decreased from adenoma to carcinoma (P < .0001, both adenoma versus borderline and borderline versus carcinoma), indicating that programmed cell death 4 might inhibit tumor progression in intraductal papillary mucinous neoplasm. Programmed cell death 4 expression had a strong relationship with p21 expression (P < .0001) and an inverse correlation with Ki-67 labeling index (r = -0.6255, P < .0001). Thus, programmed cell death 4 might inhibit the proliferation of intraductal papillary mucinous neoplasm; and its inhibition might partly result from cell cycle arrest caused by the up-regulation of p21. In conclusion, programmed cell death 4 may inhibit tumor progression in intraductal papillary mucinous neoplasm; and the loss of programmed cell death 4 expression is representative of the malignant potential of intraductal papillary mucinous neoplasm including the proliferative activity. Therefore, programmed cell death 4 can be an important biomarker for intraductal papillary mucinous neoplasm.

Characterization of CD24 expression in intraductal papillary mucinous neoplasms and ductal carcinoma of the pancreas.

CD24 is a molecule involved in cell adhesion and tumor metastasis. The aims of this study were (1) to evaluate the association between CD24 expression and the progression of intraductal papillary mucinous neoplasms of the pancreas and (2) to investigate the association between CD24 expression in pancreatic cancer and the prognosis of patients who underwent curative pancreatectomy. Immunohistochemical analysis of CD24 was performed for 95 intraductal papillary mucinous neoplasms of the pancreas and 83 pancreatic cancers. We investigated the association between CD24 expression and the histologic grade of intraductal papillary mucinous neoplasms of the pancreas, the clinicopathologic parameters of pancreatic cancers, and the survival time of pancreatic cancer patients who underwent pancreatectomy. The positive rates of CD24 expression in intraductal papillary mucinous adenoma, borderline intraductal papillary mucinous neoplasm, noninvasive intraductal papillary mucinous carcinoma, and invasive intraductal papillary mucinous carcinoma were 5 (20%) of 24, 12 (48%) of 25, 10 (43%) of 23, and 15 (65%) of 23, respectively. The CD24-positive rates were significantly higher in borderline intraductal papillary mucinous neoplasm and intraductal papillary mucinous carcinoma compared with intraductal papillary mucinous adenoma (P = .046 and P = .007, respectively). The staining scores, which were determined from the percentage of stained cells and the staining intensity, were significantly higher in invasive intraductal papillary mucinous carcinoma than in noninvasive intraductal papillary mucinous carcinoma (P = .043). In the pancreatic cancers, higher tumor stage (P = .007), nodal metastasis (P = .021), and higher-grade tumors (P < .001) were more frequent in the CD24-positive group compared with the CD24-negative group. CD24 expression was associated with shorter survival in univariate analysis (P = .028) However, based on the multivariate analysis, the CD24 expression was not associated with survival. In conclusion, CD24 is involved in the progression of intraductal papillary mucinous neoplasms of the pancreas and in the malignant behavior of pancreatic cancers.

Decreased expression of focal adhesion kinase is associated with a poor prognosis in extrahepatic bile duct carcinoma.

Extrahepatic bile duct (EBD) carcinoma is a relatively rare neoplasm worldwide, and its prognostic outcome remains unfavorable. Therefore, it is necessary to investigate molecular biologic features of EBD carcinomas. Focal adhesion kinase (FAK) plays a pivotal role in cell adhesion, survival, migration, and signal transduction, but FAK expression in EBD carcinomas has not been evaluated. We measured FAK expression in 76 EBD carcinomas using immunohistochemistry and evaluated its correlation with tumor progression, clinicopathologic factors, and patient outcome. FAK was expressed specifically in the cytoplasm of all normal biliary epithelia (100%). Most dysplastic epithelia also showed positive FAK expression except for 2 cases (92%), whereas EBD carcinomas showed positive FAK expression in 53 (77%) of 76 cases (P < .001, versus normal epithelia). FAK expression tended to be gradually reduced along as dysplasia progressed to carcinoma. Although FAK expression had no association with clinicopathologic factors, the positive FAK expression group showed significantly better survival than the negative FAK expression group (P < .05). However, FAK expression was not an independent prognostic factor by multivariate analysis. In conclusion, FAK expression was significantly lower in EBD carcinomas than in normal biliary epithelia and decreased expression of FAK seemed to be indicative of a poor prognosis, suggesting that FAK might play an inhibitory role for tumor progression in EBD carcinomas. It is important to notice the role of FAK in tumor progression when treatments targeting FAK are performed.

S100P is a novel marker to identify intraductal papillary mucinous neoplasms.

Intraductal papillary mucinous neoplasms of the pancreas are subclassified based on morphological features, and different immunohistochemical profiles have been identified in association with the subtypes. We previously reported that S100P was an early developmental marker of pancreatic carcinogenesis and that there was higher S100P expression in intraductal papillary mucinous neoplasms than in normal pancreatic ductal epithelium. However, there have been no reports on novel diagnostic markers to distinguish intraductal papillary mucinous neoplasm from nonneoplastic lesions. Surgical specimens of intraductal papillary mucinous neoplasm obtained from 105 patients were investigated using immunohistochemistry. S100P expression was not detected in normal pancreatic ductal epithelium but was detected in all intraductal papillary mucinous neoplasm cells (100%) with diffuse nuclear or nuclear/cytoplasmic staining. MUC5AC was also expressed in most of the intraductal papillary mucinous neoplasms (102/105; 97%). Furthermore, S100P was clearly expressed in the invasive component of intraductal papillary mucinous neoplasms (32/32; 100%), including perineural and lymphatic and minimal invasion. On the other hand, MUC5AC was expressed in only 23 cases of 32 invasive components (P < .01). These data suggest that the S100P antibody may be a useful marker for detecting all types of intraductal papillary mucinous neoplasms.

CD44v6 expression in intraductal papillary mucinous neoplasms of the pancreas.

OBJECTIVES: The purpose of this study was to examine CD44v6 expression in intraductal papillary mucinous neoplasms (IPMNs) and clarify the role of CD44v6 in progression, invasion, metastasis, and morphogenesis of IPMNs. METHODS: One hundred fifty-one samples of IPMNs and 30 normal controls were subjected to immunohistochemical analysis for CD44v6. The IPMNs were divided into 4 groups according to the grade of atypia (adenoma, borderline IPMN, noninvasive carcinoma, and invasive carcinoma) and 5 subtypes according to histological phenotype (gastric, intestinal, pancreatobiliary, oncocytic, and unclassified). Correlations were investigated between CD44v6 expression and clinicopathological characteristics including grade of atypia, subtype, lymph node metastasis, and invasion pattern. RESULTS: Whereas normal ductal epithelium did not express CD44v6, CD44v6 expression was observed from the early stage of IPMNs and up-regulated in the progression of IPMNs to invasive carcinoma. CD44v6 expression in intestinal-type IPMNs was significantly lower compared with that in other subtypes. Whereas no correlation was observed between lymph node metastasis and CD44v6 expression in invasive IPM carcinomas, the invasion pattern was significantly correlated to CD44v6 expression. CONCLUSIONS: The present data indicate that CD44v6 expression determines the morphology and aggressiveness of IPMNs and is involved in development and invasion of IPMNs.

CD10+ fibroblasts are more involved in the progression of hilar/extrahepatic cholangiocarcinoma than of peripheral intrahepatic cholangiocarcinoma.

AIMS: To identify the role of CD10 expression of tumour-associated fibroblastic cells in the progression of cholangiocarcinoma (CC). METHODS AND RESULTS: The CD10 expression of fibroblastic cells was investigated immunohistochemically in 167 cases of intrahepatic and extrahepatic CC and 29 cases of biliary dysplasia, comparing the clinicopathological parameters. CD10 expression of fibroblastic cells was observed in 5.7% (4/70) of peripheral intrahepatic CC, 29.2% (14/48) of hilar intrahepatic CC, and 57.1% (28/49) of extrahepatic CC. As for biliary dysplasia, CD10 expression of fibroblastic cells was observed in 4.3% (1/23) in the hepatic hilum and 20% (3/15) in the extrahepatic bile duct. CD10 expression had a strong relationship with the anatomical location of CC, and was more frequently detected in the periductal infiltrating type of hilar intrahepatic CC (P < 0.0001) and in less differentiated cases in extrahepatic CC (P = 0.0151). CD10 expression was observed more frequently in CC than in biliary dysplasia of hepatic hilum (P = 0.0365) and extrahepatic bile duct (P = 0.0262). CD10 expression was not a prognostic indicator in CC. CONCLUSIONS: We suggest that CD10+ fibroblasts are more involved in the progression of hilar and extrahepatic CC than of peripheral intrahepatic CC.

LMO2 is a novel predictive marker for a better prognosis in pancreatic cancer.

PURPOSE: LIM domain only 2 (LMO2) has been identified as a novel oncogene associated with carcinogenesis and better prognosis in several malignant tumors. We investigate the involvement of LMO2 in pancreatic cancer. EXPERIMENTAL DESIGN: We evaluated LMO2 expression in cultured cells, bulk tissues, and microdissected cells from pancreatic cancers by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. RESULTS: Of 164 pancreatic cancers, 98 (60%) were positive for LMO2 expression. LMO2 was more frequently detected in high-grade pancreatic intraepithelial neoplasia (PanIN) lesions (PanIN-2 and -3) than in low-grade PanIN lesions (PanIN-1A and -1B; P < .001) and was not detected in normal pancreatic ductal epithelium. The LMO2 messenger RNA levels were significantly higher in invasive ductal carcinoma cells than in normal pancreatic cells as evaluated by quantitative reverse transcription-polymerase chain reaction analyses of microdissected cells (P = .036). We also found higher incidence of LMO2 expression in histologic grade G1/G2 cancers than in grade G3 cancers (P < .001). The median survival time of LMO2-positive patients was significantly longer than that of LMO2-negative patients (P < .001), and multivariate analyses revealed that high LMO2 expression was an independent predictor of longer survival (risk ratio, 0.432, P < .001). Even among patients with a positive operative margin, LMO2-positive patients had a significant survival benefit compared with LMO2-negative patients. We further performed a large cohort study (n = 113) to examine the LMO2 messenger RNA levels in formalin-fixed paraffin-embedded samples and found similar results. CONCLUSIONS: LMO2 is a promising marker for predicting a better prognosis in pancreatic cancer.

REG4 is associated with carcinogenesis in the 'intestinal' pathway of intraductal papillary mucinous neoplasms.

Subclassification of intraductal papillary mucinous neoplasms of the pancreas (IPMNs), based on morphological features and immunohistochemical profiles, has been proposed. Intestinal-type IPMNs frequently show moderate to severe dysplasia. Regenerating islet-derived family, member 4 (REG4) is associated with the adenoma-carcinoma sequence in colon cancer and it is also associated with intestinal phenotype. Therefore, to identify REG4 expression in IPMNs may be helpful to detect high-grade IPMNs. We also investigated REG4 expression and CDX2 expression in IPMNs. To investigate the expressions of REG4 and CDX2 in IPMNs and in invasive ductal adenocarcinoma derived from IPMN, we used immunohistochemical staining and microdissection-based quantitative real-time reverse transcription-polymerase chain reaction. Among 125 IPMNs, 43 (34%) were positive for REG4 and most of the intestinal-type IPMNs showed its expression (35/38). The positive ratio of REG4 expression in colloid carcinoma (5/7) was significantly higher than that in tubular carcinoma (1/17; P=0.003). Most of CDX2-positive cases (31/33) expressed REG4 protein, whereas only 12 of 92 CDX2-negative cases did (P<0.001). The levels of REG4 mRNA in intestinal-type IPMN were significantly higher compared to those in gastric-type IPMN or to normal pancreatic ductal epithelium (P=0.005, P=0.004, respectively). REG4 expression was observed more frequently in borderline lesions (14/28) and carcinoma (21/45) compared to adenoma (8/52). Using the Ki-67 labeling index, REG4 expression was significantly correlated with proliferative activity in borderline lesions. We conclude that REG4 is involved in the 'intestinal' pathway of carcinogenesis in IPMN.