Pancreatic intraepithelial neoplasia and infiltrating adenocarcinoma: analysis of progression and recurrence by DPC4 immunohistochemical labeling.

Pancreatic intraepithelial neoplasia (PanIN) is thought to be a precursor lesion of infiltrating pancreatic ductal adenocarcinoma (IPA). DPC4 is a tumor-suppressor gene on chromosome 18q21.1 and is inactivated in approximately 55% of IPAs. Recently, immunohistochemical labeling using a monoclonal antibody to the Dpc4 protein has been shown to mirror DPC4 genetic status in invasive adenocarcinomas of the pancreas. In the present study, we examined the role of Dpc4 loss in neoplastic progression and recurrence. Two cases in which a PanIN clinically progressed to an invasive adenocarcinoma and a third of a patient with IPA of the head of the pancreas who later developed invasive adenocarcinoma in the tail of the pancreas were studied using Dpc4 immunolabeling. The first patient underwent pancreatic resection, which revealed PanIN-3 that lacked Dpc4 expression, and the patient developed an invasive pancreatic ductal carcinoma 10 years later that shared this loss of expression. The second patient had a pancreaticoduodenectomy for recurrent pancreatitis, and the resected pancreas contained PanIN-3 with intact Dpc4 expression. Seventeen months later, the patient developed an invasive adenocarcinoma of the distal pancreas that also had intact Dpc4 expression. In the third case, the patient underwent pancreaticoduodenectomy for an invasive ductal adenocarcinoma with negative margins. This carcinoma lacked Dpc4 expression. Three years later, resection of the pancreatic tail showed a second invasive adenocarcinoma. The cancer in the tail of the gland showed intact Dpc4 expression, suggesting it represented a second primary tumor, not a recurrence. We conclude that Dpc4 expression in PanIN can be predictive of Dpc4 expression in the subsequent invasive ductal adenocarcinoma. Additionally, Dpc4 expression can be used to differentiate recurrent or persistent adenocarcinoma from a second primary adenocarcinoma.     

Molecular and immunohistochemical analysis of intraductal papillary neoplasms of the biliary tract

Intraductal papillary neoplasms (IPNs) of the biliary tract are uncommon lesions that may be solitary or may spread extensively along the biliary tree. Some biliary IPNs are histologically and radiologically similar to intraductal papillary mucinous tumors (IPMNs) of the pancreas and present a risk for progression to invasive cholangiocarcinoma. Unlike pancreatic IPMNs, little is known about their molecular pathogenesis. We studied 14 biliary IPNs (including 5 cases with associated invasive cholangiocarcinoma) for genetic alterations in the APC/beta-catenin pathway, K-ras oncogene mutations, p53/chromosome 17p alterations, and Dpc4/18q alterations. Immunohistochemistry was performed for beta-catenin, p53, and Dpc4, and microdissected tissue was analyzed using direct DNA sequencing for exon 1 of K-ras and exon 3 of beta-catenin and allelic loss assays on chromosomes 5q, 17p, and 18q. Activating mutations in codon 12 of the K-ras oncogene were present in 4 of 14 (29%) biliary IPNs. Of these 4 cases, 2 patients had associated invasive cholangiocarcinoma, and identical K-ras mutations were present in both the intraductal and invasive components. Allelic loss on chromosome 18q was present in 4 of 13 informative cases (31%); however, no loss of normal Dpc4 expression was detected by immunohistochemistry. Nuclear accumulation of beta-catenin protein was demonstrated in 3 of 12 cases (25%); however, there were no beta-catenin gene mutations, and allelic loss on 5q was present in only 1 of 10 informative cases (10%). Both immunohistochemistry for p53 and 17p allelic loss assays were negative. Biliary IPNs therefore demonstrate a K-ras gene mutation frequency that is lower than that previously reported for pancreatic IPMNs, but similar to that reported for hepatic cholangiocarcinomas. The presence of K-ras mutations in 2 purely intraductal neoplasms, and identical K-ras mutations in 2 cases with both intraductal and invasive components, suggests that these mutations arise early in tumorigenesis. Finally, the frequency of allelic loss on 18q suggests that a locus on 18q is involved in the molecular pathogenesis of biliary IPNs, but this locus is not DPC4.     

Invasive papillary carcinomas of the extrahepatic bile ducts: a clinicopathologic and immunohistochemical study of 13 cases.

Carcinomas of the extrahepatic bile ducts are uncommon neoplasms that are morphologically heterogeneous and associated with a poor prognosis. We have previously shown that the noninvasive and minimally invasive papillary carcinomas of the extrahepatic bile ducts behave as in situ carcinomas and are associated with a better prognosis. We reviewed the clinical records of 13 patients with invasive papillary carcinomas of the extrahepatic bile ducts and analyzed the microscopic features and selected immunohistochemical reactivity (p53, Mib-1, and Dpc4) that might correlate with patient survival. In addition, we present the updated SEER (Surveillance, Epidemiology, and End Results) data of the National Cancer Institute for the invasive extrahepatic bile duct carcinomas compiled from 1975 to 1998. The 13 patients with papillary carcinoma had a male to female ratio of 1:1, and their ages ranged from 33 to 89 years. Painless jaundice and abdominal pain were the most common complaints. Five tumors were located in the distal portion, one in the mid portion, and six in the proximal portion of the common bile duct. One papillary carcinoma arose in the right hepatic duct. The Whipple procedure was performed in six patients, common bile duct resection in six, and right hepatic lobectomy in one. The cell phenotype of the papillary carcinomas was biliary in nine and intestinal in three. One tumor had both biliary and intestinal phenotypes. Four tumors dedifferentiated (two to undifferentiated small cell carcinomas, one to small [oat] cell carcinoma, and one to giant cell carcinoma). Two papillary carcinomas extended into the pancreas and three into the liver. Only one patient had lymph node metastases at presentation. Follow-up was available in 10 patients. Six patients died of disease from 2 weeks to 2 years and 1 month after surgery. Four patients are alive with no evidence of disease from 4 months to 8 years and 8 months after surgery. Of 174 invasive papillary carcinomas compiled by the SEER program, 71 were confined to the ductal wall, and 61 had regional lymph node metastases. Papillary carcinomas confined to the ductal wall have better 10-year relative survival rates than adenocarcinomas limited to the wall (21% versus 12%). Likewise papillary carcinomas with lymph node metastasis have better prognosis than adenocarcinoma with nodal metastases (10-y survival rate of 12% versus 5%). Currently, the histologic type and the stage of the disease are the most important prognostic factors in these papillary carcinomas. Separation of invasive and noninvasive or minimally invasive papillary carcinoma is critical in estimating the patient outcome. Our findings suggest that there is no correlation between p53, Ki-67, and Dpc4 expression in these tumors and survival of the patients.     

Endometrial adenocarcinoma in situ in complex atypical hyperplasia: correlation with findings in subsequent hysterectomy specimen

Well-differentiated endometrial adenocarcinoma can be difficult to distinguish from complex atypical hyperplasia (CAH) in a curettage or biopsy specimen. When a focus of back-to-back glands or cribriforming smaller than 2.1 mm is seen in a biopsy, we make a diagnosis of adenocarcinoma in situ (AIS). Whether this diagnosis translates into a more frequent diagnosis of carcinoma on the hysterectomy specimen is unknown. The objective of this study was to compare follow-up hysterectomy findings in biopsies showing AIS in CAH with biopsies showing only CAH without AIS. Twelve biopsy/curettage cases diagnosed as endometrial AIS in CAH and 12 biopsy/curettage cases diagnosed as CAH only were reviewed and correlated with corresponding hysterectomy material. A diagnosis of AIS was designated on biopsy/curettings when a focus of back-to-back glands or cribriforming less than 2.1 mm was present. Hysterectomy specimens showed endometrial carcinoma in 6 (50%) of 12 cases of CAH with AIS, and in 2 (17%) of 12 cases diagnosed as CAH only. Endometrial carcinoma with myometrial invasion was identified in 5 (42%) of the cases showing AIS on biopsy, but in none of the 12 cases diagnosed as CAH only on biopsy. Identification of AIS in CAH cases provides useful prognostic information.     

Immunohistochemical and genetic analysis of non-small cell and small cell gallbladder carcinoma and their precursor lesions.

Gallbladder carcinomas can be highly lethal neoplasms. Relatively little is known about the genetic abnormalities that underlie these tumors, particularly with respect to their timing in neoplastic progression. The authors evaluated 5 noninvasive dysplasias and 33 invasive gallbladder carcinomas (6 small cell carcinomas, 27 non-small cell carcinomas, of which 16 were accompanied by an in situ carcinoma component) for expression of the protein products of the p16, p53, Dpc4, and pRB tumor suppressor genes by immunohistochemistry. Neoplasms were also evaluated for the presence of activating K-ras oncogene mutations. Seventy-five percent of non-small cell gallbladder carcinomas demonstrated loss of p16 expression, whereas 63% accumulated high levels of p53. Loss of Dpc4 and pRB expression was less frequent, seen in 19% and 4% of the neoplasms, respectively. Thirty percent of neoplasms harbored activating K-ras mutations. In contrast, 100% of the small cell carcinomas of the gallbladder demonstrated inactivation of the pRB/p16 pathway; 67% showed loss of pRB expression, and the other 33% lost p16 expression. Eighty-three percent of small cell carcinomas accumulated high levels of p53, whereas loss of Dpc4 expression and activating K-ras mutations were not found. Among 15 evaluable in situ components, 13 harbored the same alterations found in the invasive component. Inactivation of p16 and p53 occur in the majority of non-small cell gallbladder carcinomas. Dpc4 inactivation and K-ras mutations occur in a significant minority of cases. pRB loss is uncommon in non-small cell gallbladder carcinoma, but virtually all small cell carcinomas inactivate the p16/pRB pathway, usually by retinoblastoma protein loss. It is noteworthy that all of these alterations occur at the level of carcinoma in situ.     

Role of the DPC4 tumor suppressor gene in adenocarcinoma of the ampulla of Vater: analysis of 140 cases.

The K-ras oncogene is activated in approximately 90% of pancreatic adenocarcinomas, and the DPC4 (MADH4/SMAD4) tumor suppressor gene is inactivated in approximately 55% of pancreatic adenocarcinomas. The contributions of these genetic alterations to the development of adenocarcinoma of the ampulla of Vater have not been fully established. One hundred forty surgically resected ampullary adenocarcinomas (76 with associated adenomas with high-grade dysplasia) were immunohistochemically labeled for the DPC4 gene product, and in 85 cases the results were correlated with the status of the K-ras oncogene from previously reported data. The results were correlated with clinical outcome and with other pathologic predictors of prognosis. Complete loss of Dpc4 labeling was identified in 34% (95% confidence interval [CI]: 26%, 43%) of the invasive carcinomas and in none (upper 95% CI: 6%) of the associated adenomas. Focal loss of Dpc4 was seen in three (4%; 95% CI: 1%, 14%) of the areas of high-grade dysplasia. Complete loss of Dpc4 expression was seen in 28/77 intestinal-type tumors, in 17/46 pancreaticobiliary-type tumors, and in 0/10 colloid carcinomas. Activating point mutations in the K-ras gene were identified in 40% of the invasive cancers. There was no correlation between K-ras gene mutations and Dpc4 expression and no correlation between these variables and survival. The overall 5-year survival rate was 38%. Lymph node metastases were associated with shorter survival (P =.03). Loss of Dpc4 expression occurs in approximately one third of invasive ampullary cancers but is not seen in adenomas; thus, loss of Dpc4 expression occurs late in ampullary carcinogenesis. Although ampullary and pancreatic adenocarcinomas share histologic and molecular features, ampullary carcinomas are less likely to show loss of Dpc4 expression or K-ras gene mutations.     

Brush cytology of the biliary tract: retrospective study of 278 cases with histopathologic correlation

Bile aspiration during endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography has been used as a diagnostic tool in the evaluations of pancreatic and biliary tree strictures for the last two decades. However, recently biliary tract brush cytology has become the method of choice in evaluating pancreatic/biliary tract abnormalities. The aim of this study was to evaluate the accuracy of pancreatobiliary lesions by an endobiliary cytotechnique. From 1993-1999, 278 pancreatobiliary brushings were performed at our institutions. Cytologic material was air-dried for Diff-Quik stain or fixed in ethanol for Papanicolaou staining. The cytologic diagnoses were classified in three categories: 1) benign, 2) atypical/suspicious, or 3) malignant. Subsequent surgical biopsy was available in 87 (31%) patients. There were 150 males and 128 females with a mean age of 63 yr (range 22-97); 167 (60%) were benign cases. Follow-up surgical material was available in 39 cases, seven of which showed adenocarcinoma; 67 of all cases (24%) were atypical/suspicious cases. Follow-up surgical material was available in 31 cases, 17 (55%) of which showed adenocarcinoma; 32 cases (12%) were malignant cases. Follow-up surgical material was available in 15 cases. All 15 cases were in agreement with the cytologic diagnosis. Twelve (4%) cases were unsatisfactory for cytologic examination. Follow-up surgical material was available in two cases. One case showed mucinous cystadenoma of the pancreas. The other case showed benign duct epithelium. Our study shows a sensitivity of 68% and a specificity of 100%. Of the atypical cases, 55% were malignant on follow-up biopsy. Brush cytology of pancreatobiliary strictures is the most widely used technique in the diagnosis of carcinoma, with a high degree of specificity.     

Percutaneous transhepatic biliary biopsy using gastrofiberscopic biopsy forceps.

To obtain a histopathologic diagnosis at the site of a biliary obstruction, we recently have performed 24 cases of biliary biopsy using gastrofiberscopic biopsy forceps (Olympus, Tokyo, Japan) via transhepatic tracts provided in the course of the procedure of percutaneous biliary drainage. Histopathologic diagnosis was successfully made at the first attempt of biopsy procedure but a second trial was made a week later in 6 cases who were negative for malignant cells on the first attempt. The histological results from the biopsy specimens were 18 adenocarcinomas, 5 chronic inflammations and one normal epithelium. Of 6 cases who were negative for malignant cells on forceps biopsy specimen, three cases were confirmed as adenocarcinoma of the ampulla of Vater, adenocarcinoma of the pancreas and chronic pancreatitis by surgical biopsy. The latter was a true negative result, which was diagnosed as chronic inflammation on forceps biopsy and verified as chronic pancreatitis by surgery. The remaining two cases were diagnosed as malignant obstructive jaundice by clinical and radiological follow-up findings. Major complications (bile peritonitis, bleeding, and hemopneumothorax) occurred in 3 patients, which mainly arose in the earlier period of study. This procedure can be performed at the same time as percutaneous transhepatic biliary drainage with low morbidity or mortality, and although the potential for perforation of bile ducts and injury to adjacent blood vessels is considered it is a useful addition to existing biopsy techniques for yielding material sufficient for histologic analysis.     

The significance of the P504S expression pattern of high-grade prostatic intraepithelial neoplasia (HGPIN) with and without adenocarcinoma of the prostate in biopsy and radical prostatectomy specimens

Diagnosis of prostatic adenocarcinoma is usually not difficult in biopsy specimens. Problems may occur in biopsy specimens, containing only a few suspicious lesions. Recently, P504S has been tested as a new marker for prostatic carcinoma. When over-expressed in atypical glands without basal cells, it establishes the diagnosis of prostatic carcinoma. We analysed the staining intensity of P504S in 208 biopsy specimens from prostates (1) with adenocarcinoma (n=132), (2) with high-grade prostatic intraepithelial neoplasia (HGPIN) with adenocarcinoma (n=36), (3) with HGPIN alone (n=40) and in radical prostatectomy specimens with HGPIN adjacent to (n=54) or distant from adenocarcinoma (n=64). P504S expression was negative to weakly positive in biopsy specimens showing HGPIN without carcinoma and weakly positive in radical prostatectomy specimens revealing HGPIN distant from adenocarcinoma. In biopsy specimens with a combination of HGPIN and adenocarcinoma and in radical prostatectomy specimens with HGPIN adjacent to adenocarcinoma, P504S was strongly expressed. The same findings were made in radical prostatectomy specimens containing adenocarcinoma and HGPIN adjacent to or distant from adenocarcinoma and in preoperative biopsies revealing adenocarcinoma and HGPIN. These results suggest that moderate to strong P504S expression in HGPIN of biopsy specimens is indicative of an associated adenocarcinoma and may be helpful in the choice of therapy.     

Expression of cell cycle-related molecules in biliary premalignant lesions: biliary intraepithelial neoplasia and biliary intraductal papillary neoplasm

Cholangiocarcinoma of intrahepatic and extrahepatic bile ducts has a multistep carcinogenesis. Two premalignant lesions have been suggested for invasive cholangiocarcinoma: biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. How the carcinogenetic process differs between biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct is not clear. In this study, we performed a pathological study to reveal the expression of key molecules related to the cell cycle during 2 carcinogenetic lineages. We immunohistochemically examined the expression of p21, p53, cyclin D1, and Dpc4 in a total of 89 cases: nonneoplastic biliary epithelium, biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and invasive cholangiocarcinoma. The expression of p21, p53, and cyclin D1 was up-regulated with histological progression in both biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct, whereas Dpc4 expression was down-regulated in these 2 lineages. In biliary intraepithelial neoplasia, p21 expression was significantly up-regulated early on. In contrast, levels of all molecules changed gradually in intraductal papillary neoplasm of the bile duct. Changes in p53 expression during histological progression differed significantly between biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. p53 expression was dramatically up-regulated at the invasive stage of biliary intraepithelial neoplasia, whereas it was quite low in noninvasive biliary intraepithelial neoplasia. In contrast, p53 expression was already up-regulated in low-grade intraductal papillary neoplasm and reached a plateau in high-grade intraductal papillary neoplasm and invasive cholangiocarcinoma. This study suggested p21, p53, cyclin D1, and Dpc4 to be involved in the carcinogenesis of both biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. p53 expression was regulated differently in biliary intraepithelial neoplasia compared with intraductal papillary neoplasm of the bile duct.     

Ampulla of vater cancers: T-stage and histological subtype but not Dpc4 expression predict prognosis

Loss of immunohistochemical expression of Dpc4 occurs in about 50% of pancreatic ductal cancers and its loss correlates with DPC4/Smad4 gene inactivation. Dpc4 expression was also lost in 6 of 16 (37%) ampulla of Vater cancers (AVCs) previously analyzed. Furthermore, chromosomal losses involving 18q, where DPC4 is located, have been observed in 34% of AVCs and are associated with decreased survival. To evaluate the possibility that expression of Dpc4 may be correlated with survival, we analyzed 89 AVCs for inactivation of DPC4 by immunohistochemical staining. Thirty-seven cases showed no expression of Dpc4 (41%). Multivariate survival analysis was performed including age, sex, tumor size, histological subtype (intestinal or pancreatobiliary), grade of differentiation, T-stage, lymph-node metastases and Dpc4 status. T-stage and histological subtype were selected as independent prognostic factors, while Dpc4 immunostaining was not significantly associated with any clinicopathological variable, including histological subtype. Although Dpc4 expression is of no clinical relevance, its involvement in AVC gives additional weight to the hypothesis that, among all pancreatic exocrine and endocrine tumors, only AVC and common ductal adenocarcinomas have similar molecular fingerprints. Moreover, comparison of the frequencies of allelic loss on chromosomal arm 18q and the loss of Dpc4 expression (34% and 41%, respectively) is highly suggestive that DPC4 is the major target of these losses.     

Intraglandular necrotic debris in gastric biopsy and surgical specimens.

To clarify whether intraglandular necrotic debris (IND) is a diagnostic clue to noninvasive high-grade neoplasia or invasive neoplasia of the stomach, we reviewed 135 gastric biopsy specimens and 55 surgical materials. Intraglandular necrotic debris is defined as an eosinophilic material with necrotic epithelial fragments within the lumen of a dilated atypical gland. Using the Vienna classification, the incidence of IND in category 4 (noninvasive high-grade neoplasia) and category 5 (invasive neoplasia) was significantly higher than that of category 1 (negative for neoplasia/dysplasia), category 2 (indefinite for neoplasia/dysplasia), and category 3 (noninvasive low-grade neoplasia). The incidence of IND was much higher in category 5 than in category 4 in biopsy specimens. In addition, cases with IND in category 4 in biopsy specimens turned out to be either carcinoma in situ or invasive carcinoma in the surgical specimens. According to the histologic classification of surgically removed invasive carcinoma, moderately differentiated adenocarcinoma showed the highest incidence of IND. Intraglandular necrotic debris was not found in either signet-ring cell carcinoma or mucinous adenocarcinoma. Our results indicate that IND in biopsy specimens is a diagnostic clue to noninvasive high-grade neoplasia or invasive carcinoma, and the origin of IND may be associated with necrotic atypical epithelium.     

Loss of E-cadherin and cytoplasmic-nuclear expression of beta-catenin are the most useful immunoprofiles in the diagnosis of solid-pseudopapillary neoplasm of the pancreas

Solid-pseudopapillary neoplasm of the pancreas occurs preferentially in young women and has a favorable prognosis. Differentiation of solid-pseudopapillary neoplasm from pancreatic endocrine neoplasm or adenocarcinoma can be difficult in the small biopsy specimen because they share common morphological features and immunoprofiles. Alterations of adenomatous polyposis coli (APC)/beta-catenin pathway have been identified as a genetic event contributing to the development of solid-pseudopapillary neoplasm. In the present study, to establish the diagnostic utility of beta-catenin and E-cadherin as markers for solid-pseudopapillary neoplasm, we performed immunohistochemical staining in 4 core biopsy specimens diagnosed as solid-pseudopapillary neoplasm and in tissue microarray blocks that contained histologically confirmed samples of 302 cases of adenocarcinoma, 56 cases of pancreatic endocrine neoplasm, and 50 cases of solid-pseudopapillary neoplasm. We compared the immunohistochemical results for beta-catenin and E-cadherin with those for known markers. Of the solid-pseudopapillary neoplasm cases, 51 (94.4%) were positive for nuclear beta-catenin, 45 (83.3%) were positive for CD10, 30 (55.5%) were positive for CD56, 15 (27.8%) were positive for synaptophysin, 3 (5.6%) were positive for cytokeratin (CK), and none was positive for E-cadherin and chromogranin. Of the adenocarcinoma cases, all were positive for CK, 300 (99.3%) were positive for E-cadherin, 30 (9.9%) were positive for CD10, 2 (0.7%) were positive for synaptophysin, 1 (0.3%) was positive for CD56, and none was positive for chromogranin and nuclear expression of beta-catenin. Of the pancreatic endocrine neoplasm cases, 54 (96.4%) were positive for synaptophysin and E-cadherin, 50 (89.3%) were positive for chromogranin, 26 (46.4%) were positive for CK, 15 (26.8%) were positive for CD56, 6 (10.7%) were positive for CD10, and none was positive for nuclear expression of beta-catenin. In conclusion, nuclear expression of beta-catenin and loss of E-cadherin can be used in the definite diagnosis of solid-pseudopapillary neoplasm on small biopsy specimens. CD10 immunopositivity should be carefully interpreted in the diagnosis of solid-pseudopapillary neoplasm because pancreatic adenocarcinoma or pancreatic endocrine neoplasm can also stain for CD10.     

Allelic loss is often the first hit in the biallelic inactivation of the p53 and DPC4 genes during pancreatic carcinogenesis

The presumed precursor lesions of pancreatic ductal adenocarcinoma were recently classified according to their increasing grade of dysplasia and were designated as pancreatic intraepithelial neoplasia (PanIN) 1 through 3. In this study, we tested whether molecular genetic alterations can be correlated with this classification and may help to further categorize the various PanIN grades. We determined the frequencies of allelic loss at chromosomal arms 9p, 17p, and 18q in 81 microdissected duct lesions of various PanIN grades, using a combination of whole genome amplification and microsatellite analysis. In addition we examined the p53 and Dpc4 protein expression patterns by immunohistochemical analysis. In PanIN-1, we did not detect allelic losses. In PanIN-2, allelic losses were found in increasing frequency, and were particularly high in those lesions with moderate-grade dysplasia (low grade, 20, 33, and 17%, loss at 9p, 17p, and 18q, respectively; moderate grade, 46, 77, and 58%). PanIN-3 and invasive carcinomas exhibited abundant losses. Abnormal p53 and Dpc4 protein expression was only rarely identified in PanIN-2 lesions, but occurred frequently in PanIN-3 lesions and invasive carcinomas. The combined genetic and protein expression data support a model in which allelic loss is the first hit in the biallelic inactivation of the p53 and DPC4 tumor suppressor genes. In addition, our data indicate that allelic loss analysis may be useful in separating PanIN-2 lesions with low-grade dysplasia from those PanIN-2 lesions with moderate-grade dysplasia, each potentially representing a distinct progression step toward invasive carcinoma.     

Preoperative and intraoperative diagnosis of low-grade adenosquamous carcinoma of the breast: potential diagnostic pitfalls

AIMS: Low-grade adenosquamous carcinoma (LGAC), a rare variant of metaplastic breast cancer, may mimic benign or other low-grade malignant lesions histologically. Diagnostic difficulty may be encountered when evaluating breast cytology, core needle biopsy or intraoperative frozen section specimens. METHODS AND RESULTS: Pathology reports, cytology aspirates and histological slides of LGAC diagnosed at the Department of Pathology, Singapore General Hospital, were reviewed. Four cases of LGAC were analysed. Cytology from the first case showed atypical cells and the subsequent surgical excision specimen showed a complex sclerosing lesion with LGAC. The second and third cases were investigated by core needle biopsies: the preoperative histological features were suggestive of but not diagnostic of LGAC, until further excision biopsies were performed. The fourth case entailed a frozen section specimen, for which definitive diagnosis was deferred to paraffins. The patients remained well with no evidence of recurrent disease to date. CONCLUSIONS: When limited material, in the form of needle aspirates, core biopsy specimens or frozen sections, is submitted for histology, making a diagnosis of LGAC is not only challenging, but may be impossible. In difficult cases, careful pathological assessment, clinicopathological correlation and follow-up or complete excision biopsy may prove invaluable in establishing a definitive diagnosis.     

Genetic and immunohistochemical analysis of pancreatic acinar cell carcinoma: frequent allelic loss on chromosome 11p and alterations in the APC/beta-catenin pathway

Acinar cell carcinomas (ACCs) are rare malignant tumors of the exocrine pancreas. The specific molecular alterations that characterize ACCs have not yet been elucidated. ACCs are morphologically and genetically distinct from the more common pancreatic ductal adenocarcinomas. Instead, the morphological, immunohistochemical, and clinical features of ACCs overlap with those of another rare pancreatic neoplasm, pancreatoblastoma. We have recently demonstrated a high frequency of allelic loss on chromosome arm 11p and mutations in the APC/beta-catenin pathway in pancreatoblastomas, suggesting that similar alterations might also play a role in the pathogenesis of some ACCs. We analyzed a series of 21 ACCs for somatic alterations in the APC/beta-catenin pathway and for allelic loss on chromosome 11p. In addition, we evaluated the ACCs for alterations in p53 and Dpc4 expression using immunohistochemistry, and for microsatellite instability (MSI) using polymerase chain amplification of a panel of microsatellite markers. Allelic loss on chromosome 11p was the most common genetic alteration in ACCs, present in 50% (6 of 12 informative cases). Molecular alterations in the APC/beta-catenin pathway were detected in 23.5% (4 of 17) of the carcinomas, including one ACC with an activating mutation of the beta-catenin oncogene and three ACCs with truncating APC mutations. One ACC (1 of 13, 7.6%) showed allelic shifts in four of the five markers tested (MSI-high), two (15.4%) showed an allelic shift in only one of the five markers tested (MSI-low), and no shifts were detected in the remaining 10 cases. The MSI-high ACC showed medullary histological features. In contrast, no loss of Dpc4 protein expression or p53 accumulation was detected. These results indicate that ACCs are genetically distinct from pancreatic ductal adenocarcinomas, but some cases contain genetic alterations common to histologically similar pancreatoblastomas.     

Ductal adenocarcinoma of the pancreas with psammomatous calcification: report of a case with immunohistochemical study for bone morphogenetic protein

We report a case of invasive ductal adenocarcinoma of the pancreas with psammomatous calcification. A 57-year-old man was admitted to our hospital complaining of abdominal pain and vomiting. Carcinoma of the head of the pancreas was diagnosed based on precise clinical examinations. A subtotal stomach-preserving pancreaticoduodenectomy was subsequently performed. Histological examination of the surgical specimen revealed a well-differentiated adenocarcinoma composed of irregular tubular structures involving the head of the pancreas. Conspicuously, numerous tiny psammomatous-type calcifications were observed, mainly within the neoplastic lumen, but also in association with carcinoma cells that had infiltrated the lymphatics and lymph nodes. In addition, expression of bone morphogenetic protein, cartilage and bone-inducing factor cloned from demineralized bone matrix and the transforming growth factor-β subfamily was immunohistochemically examined for carcinoma cells. Reactivity for multiple kinds of bone morphogenetic protein (types 5, 6 and 7) was identified in the cytoplasm of carcinoma cells. Psammoma body formation is an unusual event in invasive ductal adenocarcinoma of the pancreas, with only one similar case previously reported in the English literature. We also discuss the formation of psammomatous calcifications by pancreatic cancer cells.     

RUNX3蛋白表达与胃腺癌病理分化程度关系的研究

目的：探讨RUNX3基因表达在胃腺癌中的表达情况及意义。方法：采用兔抗人RUNX3蛋白抗体和ABC免疫组织化学方法检测手术切除的胃癌组织标本中染色阳性细胞数及阳性率。结果：RUNX3表达主要位于细胞核内,细胞浆也有表达,在41例胃腺癌组织中,RUNX3表达的总体阳性率为56.1%,其中低分化腺癌46.6%（7/15）,管状腺癌72.7%（8/11）,腺泡状腺癌66.7%（6/9）,其他类型腺癌33.3%（2/6）,各组间无明显的差异（P〉0.05）。病理分期为Ⅲ、Ⅳ期的胃癌RUNX3表达明显低于Ⅰ、Ⅱ期（46.6%vs70.1%,P〈0.05）,而在Ⅲ、Ⅳ期的胃癌组织中,低分化腺癌组的RUNX3表达阳性率明显低于管状腺癌组（11.1%vs71.4%,P〈0.05）。但患者的年龄、性别分组间RUNX3的表达差异无显著性（P〉0.05）。结论：在胃腺癌组织中,RUNX3的表达阳性率为56.1%,其表达与胃癌的病理分期有关。     

Observer variability in the Goseki grouping of gastric adenocarcinoma in resection and biopsy specimens

AIMS: The Goseki grouping of gastric adenocarcinoma has been suggested as a possible prognostic factor. In those centres where it is used, it may be valuable to assess the Goseki grouping of a tumour on the initial diagnostic biopsy as well as on the resection specimen since it may in theory influence management. We examined the robustness of Goseki grouping of gastric adenocarcinoma in representative sections from resection and biopsy specimens in order to assess the consistency of agreement among a group of pathologists. METHODS: A single representative block from 100 gastric resection specimens was studied using a haematoxylin and eosin and mucin (alcian blue/periodic acid-Schiff) stain. These were circulated in batches to members of a group of 12 pathologists who each completed a simple proforma confirming the presence of carcinoma and assigning a Goseki group. In a second circulation the diagnostic biopsy specimen taken prior to resection was examined in the same way. This allowed comparison of the Goseki group of the biopsy and resection specimens. RESULTS: In both studies kappa statistics showed good agreement on tubular differentiation of the carcinoma, but only moderate agreement for the intracellular mucin production, resulting in moderate agreement for the final Goseki group. Correlation between the Goseki group assigned on the biopsy and resected specimens was seen in 62% of the cases. However, the reproducibility was low (kappa 0.375). CONCLUSIONS: The Goseki grouping of resected gastric adenocarcinoma is reproducible and can be used in prognostication. Goseki grouping of biopsy specimens is of limited value in predicting the Goseki group assigned to the resected carcinoma.