p53 and p21/Waf1 protein expression and K-ras codon 12 mutation in carcinoma of the papilla of Vater

IgG4 autoantibodies and autoantigens in the context of IgG4-autoimmune disease and IgG4-related disease

Immunoglobulins are an essential part of the humoral immune response. IgG4 antibodies are the least prevalent subclass and have unique structural and functional properties. In this review, we discuss IgG4 class switch and B cell production. We review the importance of IgG4 antibodies in the context of allergic responses, helminth infections and malignancy. We discuss their anti-inflammatory and tolerogenic effects in allergen-specific immunotherapy, and ability to evade the immune system in parasitic infection and tumour cells. We then focus on the role of IgG4 autoantibodies and autoantigens in IgG4-autoimmune diseases and IgG4-related disease, highlighting important parallels and differences between them. In IgG4-autoimmune diseases, pathogenesis is based on a direct role of IgG4 antibodies binding to self-antigens and disturbing homeostasis. In IgG4-related disease, where affected organs are infiltrated with IgG4-expressing plasma cells, IgG4 antibodies may also directly target a number of self-antigens or be overexpressed as an epiphenomenon of the disease. These antigen-driven processes require critical T and B cell interaction. Lastly, we explore the current gaps in our knowledge and how these may be addressed.

Expression of HBx protein in hepatitis B virus-infected intrahepatic cholangiocarcinoma

BACKGROUND

Hepatitis B virus (HBV) is an etiological factor of intrahepatic cholangiocarcinoma (ICC), but the pathogenic mechanisms remain unclear. This study aimed to investigate the expression and possible role of HBx, an HBV-encoded potentially oncogenic protein, in HBV-infected ICC.

METHODS

Tissue samples were obtained from 54 specimens of HBV-infected ICC. Forty-four specimens were of peripheral type and 10 hilar type. Formalin-fixed, paraffin-embedded sections of the specimens were immunohistochemically stained for HBx and p53.

RESULTS

HBx expression was found in 70.4% (38/54) of the specimens, and it was more frequently seen in the peripheral type than in the hilar type (79.5% vs 30.0%, P=0.002). All three well-differentiated ICCs expressed HBx, whereas 76.9% (30/39) moderately-differentiated and 41.7% (5/12) poorly-differentiated ICCs had HBx expression (P=0.033). Patients with HBx expression had a significantly higher prevalence of elevated serum alpha-fetoprotein (P=0.033). p53 protein expression was found in 18 of 54 cases (33.3%), and was not correlated with that of HBx.

CONCLUSIONS

HBx may contribute to the pathogenesis of ICC, particularly the peripheral type. p53 abnormality may not play a significant role in HBx-mediated oncogenicity during ICC carcinogenesis.

Human equilibrative nucleoside transporter 1 and carcinoma of the ampulla of Vater: expression differences in tumour histotypes

The human equilibrative nucleoside transporter 1 (hENT1) is the major means by which gemcitabine enters human cells; recent evidence exists that hENT1 is expressed in carcinoma of the ampulla of Vater and that it should be considered as a molecular prognostic marker for patients with resected ampullary cancer. Aim of the present study is to evaluate the variations of hENT1 expression in ampullary carcinomas and to correlate such variations with histological subtypes and clinicopathological parameters. Forty-one ampullary carcinomas were histologically classified into intestinal, pancreaticobiliary and unusual types. hENT1 and Ki67 expression were evaluated by immunohistochemistry, and apoptotic cells were identified by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick end labelling (TUNEL) method. hENT1 overexpression was detected in 63.4% ampullary carcinomas. A significant difference in terms of hENT1 and Ki67 expression was found between intestinal vs. pancreaticobiliary types (P=0.03 and P=0.009 respectively). Moreover, a significant statistical positive correlation was found between apoptotic and proliferative Index (P=0.036), while no significant correlation was found between hENT1 and apoptosis. Our results on hENT1 expression suggest that classification of ampullary carcinoma by morphological subtypes may represent an additional tool in prospective clinical trials aimed at examining treatment efficacy; in addition, data obtained from Ki67 and TUNEL suggest a key role of hENT1 in tumour growth of ampullary carcinoma.

K-ras mutation in the major duodenal papilla and gastric and colonic mucosa in patients with autoimmune pancreatitis

BACKGROUND

Pancreatic cancer occurs in some patients with autoimmune pancreatitis (AIP). Significant K-ras mutations are frequently detected in the pancreas of AIP patients. AIP may be a pancreatic lesion of IgG4-related systemic disease. Gastric and colonic cancer can occur during the follow up of AIP patients. We examined K-ras mutations in the major duodenal papilla and gastric and colonic mucosa of AIP patients.

METHODS

K-ras analysis and/or immunohistochemical study was performed on the tissues of the major duodenal papilla (n = 8), gastric mucosa (n = 5), colonic mucosa (n = 3), pancreas (n = 5), common bile duct (n = 5), and gallbladder (n = 4) of 12 AIP patients.

RESULTS

Significant K-ras mutations were detected in the major duodenal papilla of 4 of 8 cases [GAT (n = 4)], in the gastric mucosa of 2 of 4 cases [AGT (n = 2)], and in the colonic mucosa of 2 of 3 cases [GAT (n = 2)]. Significant K-ras mutations were detected in the pancreas of all 5 cases [GAT (n = 5), in the common bile duct of 4 cases (GAT (n = 2), TGT (n = 1), and GCT/TGT (n = 1)], and in the gallbladder epithelium of 3 cases [GAT (n = 1), GCT (n = 1), and GTT (n = 1)]. K-ras mutations were detected in the organs associated with IgG4-related fibroinflammation with abundant infiltration of T lymphocytes and forkhead box P3-positive cells.

CONCLUSIONS

Significant K-ras mutations were frequently detected in the major duodenal papilla and gastric and colonic mucosa of AIP patients. AIP patients may have risk factors for gastric and colonic cancer, but the mechanisms of K-ras mutation and its clinical implications are not clear.

Histopathologic features and microsatellite instability of cancers of the papilla of vater and their precursor lesions

The prevalence and development of microsatellite instability (MSI) and underlying mismatch repair (MMR) deficiency in the carcinogenesis of adenocarcinomas of the papilla of Vater and their precursor lesions are not well established. We analyzed 120 ampullary adenomas (31 pure adenomas and 89 carcinoma-associated adenomas) and 170 pure adenocarcinomas for MSI, immunohistochemical expression of MMR proteins and specific histopathologic features. The most common histologic subtype was intestinal (46.5%), followed by pancreatobiliary (23.5%), poorly differentiated adenocarcinomas (12.9%), intestinal-mucinous (8.2%), and invasive papillary carcinomas (5.3%). Eight of 89 adenomas (9%) and 15/144 carcinomas (10%) showed high microsatellite instability (MSI-H), 10/89 adenomas (11%) and 5/144 carcinomas (4%) showed low microsatellite instability (MSI-L), and 71/89 adenomas (80%) and 124/144 carcinomas (86%) were microsatellite stable (MSS). MSI analysis from carcinomas contiguous with an adenomatous component (n=54) exhibited concordant results in 6/8 (75%) MSI-H and 42/46 (91.3%) MSS tumors. Of 14 carcinomas with MSI-H, 7 showed loss of MLH1 and 5/6 (83%) MLH1 promoter methylation, and 2 carcinomas showed simultaneous loss of MSH2 and MSH6. Two carcinomas and 3 adenomas with MSI-H revealed exclusive loss of MSH6. MSI-H cancers were significantly associated with intestinal mucinous subtype (P<0.001), high tumor grade (P=0.003), expansive growth pattern (P=0.044), and marked lymphoid host response (P=0.004). Patients with MSI-H carcinoma had a significantly longer overall survival (P=0.0082) than those with MSI-L or MSS tumors. Our findings indicate that the MSI-phenotype is an early event, which develops at the stage of adenoma and is reliably detectable in the precursor lesion. The MMR deficient molecular pathway of carcinogenesis is associated with a histopathologic phenotype in ampullary cancer, similar to the one that has been well described in colon cancer.

The epidemiology and pathogenesis of neoplasia in the small intestine

PURPOSE

The mucosa of the small intestine encompasses about 90% of the luminal surface area of the digestive system, but only 2% of the total annual gastrointestinal cancer incidence in the United States.

METHODS

The remarkable contrast in age-standardized cancer incidence between the small and large intestine has been reviewed with respect to the cell type patterns, demographic features, and molecular characteristics of neoplasms.

RESULTS

Particularly noteworthy is the predominance of adenocarcinoma in the colon, which exceeds 98% of the total incidence by cell type, in contrast to that of 30% to 40% in the small intestine, resulting in an age-standardized ratio of rates exceeding 50-fold. The prevalence of adenomas and carcinomas is most prominent in the duodenum and proximal jejunum. The positive correlation in global incidence rates of small and large intestinal neoplasms and the reciprocal increases in risk of second primary adenocarcinomas suggest that there are common environmental risk factors. The pathophysiology of Crohn inflammatory bowel disease and the elevated risk of adenocarcinoma demonstrate the significance of the impaired integrity of the mucosal barrier and of aberrant immune responses to luminal indigenous and potentially pathogenic microorganisms.

CONCLUSION

In advancing a putative mechanism for the contrasting mucosal susceptibilities of the small and large intestine, substantial differences are underscored in the diverse taxonomy, concentration and metabolic activity of anaerobic organisms, rate of intestinal transit, changing pH, and the enterohepatic recycling and metabolism of bile acids. Experimental and epidemiologic studies are cited that suggest that the changing microecology, particularly in the colon, is associated with enhanced metabolic activation of ingested and endogenously formed procarcinogenic substrates.

Endocrine cells in ampullary carcinoma

BACKGROUND/PURPOSE

As ampullary carcinoma originates from four anatomical regions, it may have different behaviors depending on its origin. We documented the presence of endocrine cells found in ampullary carcinoma, and we studied the clinicopathological implications of their presence.

METHODS

We immunohistochemically examined the presence of an endocrine component in 62 surgically resected specimens of ampullary carcinoma, and we studied the clinicopathological differences between endocrine component-positive cases and endocrine component-negative cases.

RESULTS

Endocrine cells were detected in 16 cases (26%); 11 cases had many endocrine cells, and five cases had scattered endocrine cells. Serotonin-positive cells were detected in all 16 cases, in which six cases had many positive cells. Several somatostatin-positive cells were detected in three cases. Endocrine cells were detected in ampulloduodenal polypoid lesions (two cases) and ampullopancreaticobiliary ducts (14 cases). The histology of 15 of the 16 endocrine component-positive ampullary carcinomas was the intestinal type. Pancreatic invasion and lymph node involvement were observed less frequently in endocrine component-positive cases (P < 0.01). There were no significant differences with respect to immunoreactivity for carbohydrate antigen (CA) 19.9, carcinembryonic antigen (CEA), and p53 overexpression, and K-ras mutations.

CONCLUSIONS

Endocrine component-positive ampullary carcinoma seemed to be derived from the ampullopancreaticobiliary common duct or the ampulloduodenum, and to behave less aggressively than endocrine component-negative carcinoma.

COX-2 expression of ampullary carcinoma: correlation with different histotypes and clinicopathological parameters

Epidemiological studies suggest that regular intake of nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with reduced incidence of gastrointestinal cancer. Several lines of evidence indicate that the antineoplastic effect of NSAIDs is attributable to COX-2 inhibition. The aim of our study was to assess COX-2 expression in a series of primary untreated ampullary carcinomas and its possible correlation with clinicopathological parameters. In the present study, 45 surgical specimens of invasive ampullary carcinomas were histologically classified into pancreaticobiliary, intestinal, and unusual types. COX-2 expression by immunohistochemical method was analyzed. High COX-2 expression was detected in 35 (77.8%) ampullary carcinomas. Among these, 20/21 (95.2%) were classified as intestinal, 9/18 (50%) pancreaticobiliary, and 6/6 (100%) unusual type. A significant statistical difference in terms of COX-2 expression was found between pancreaticobiliary vs intestinal type (P=0.002). Furthermore, a negative significant statistical correlation was found between T factor and COX-2 expression (P=0.047). The different COX-2 expression among histopathological types supports the concept of histogenetical difference of ampullary carcinomas. Furthermore, the high rate of COX-2 expression in the intestinal subtype of ampullary carcinoma may represent the rational for a histotype-tailored therapy targeting COX-2.

Increased cyclin D1 expression in cancer of the ampulla of Vater: relevance to nuclear beta catenin accumulation and k-ras gene mutation

AIMS

Several studies have reported that dysregulation of beta catenin or k-ras mutation promotes cyclin D1 expression. This study investigated the relation between cyclin D1 expression and clinicopathological parameters in carcinoma of the ampulla of Vater (CAV), and also assessed the relation between increased cyclin D1 expression and beta catenin/k-ras status in this series.

METHODS

Thirty CAVs were evaluated for cyclin D1 expression by immunohistochemistry in relation to patient clinicopathological features. Aberrant beta catenin expression and k-ras mutation were also investigated by immunostaining and direct sequencing, and related to cyclin D1 expression.

RESULTS

Increased cyclin D1 expression was seen in 17 of 30 CAVs and was significantly correlated with tumour cell proliferation and disease free survival time (p = 0.018, p = 0.018, respectively). Nuclear accumulation of beta catenin was found in nine of 30 cases, including four cases with missense mutations in exon 3 of CTNNB-1, and was significantly correlated with increased cyclin D1 expression (p = 0.003). k-ras gene mutation was detected in 12 of 30 cases, and was also significantly correlated with increased cyclin D1 expression (p = 0.026). Overall, 14 of 17 CAVs with increased cyclin D1 expression showed nuclear accumulation of beta catenin and/or k-ras mutation.

CONCLUSIONS

Increased cyclin D1 expression appears to be associated with tumour proliferation and poorer clinical outcome in CAV. It is also associated with both aberrant beta catenin expression and k-ras mutation. These results are consistent with the in vitro data that cyclin D1 can be transactivated by activated beta catenin-T cell factor/LEF and k-ras pathways.

Immunohistochemical analysis of adenocarcinoma of the small intestine: a tissue microarray study

BACKGROUND

Primary adenocarcinomas of the small intestine are rare, and the genetic mechanisms involved in their carcinogenesis remain unclear.

AIM

To examine the expression of candidate proteins in small intestinal adenocarcinomas by immunohistochemistry performed on tissue microarrays (TMAs).

METHODS

Twenty seven primary sporadic small intestinal adenocarcinomas were analysed. The TMA technique was validated by comparing immunohistochemical labelling of hMLH1 and hMSH2 on TMAs and the tissue sections they derived from. The expression of Smad4, hMSH6, beta catenin, and p53 was investigated and results compared with those obtained in 14 malignant ampullary tumours.

RESULTS

TMA technology with threefold redundancy adequately represented the immunohistochemical pattern of small intestinal adenocarcinomas. Loss of hMLH1 expression, but not hMSH2 or hMSH6, was seen in two of 27 small intestinal adenocarcinomas. All ampullary tumours showed nuclear staining for hMSH2 and hMSH6. One case showed lack of immunostaining for hMLH1. Smad4 expression was absent in five small intestinal adenocarcinomas and two ampullary tumours. Overexpression of p53 was detected in the nuclei of 14 of the 27 small intestinal adenocarcinomas, and five of the 14 ampullary tumours. Nuclear or cytoplasmic expression of beta catenin was present in all specimens.

CONCLUSION

Inactivation of the SMAD4/DPC4 gene seems to be involved in small intestinal adenocarcinoma tumorigenesis. Overexpression of p53 and abnormal expression of beta catenin are two common events, unlike the loss of expression of the DNA mismatch repair proteins (hMLH1, hMSH2, and hMSH6). The carcinogenetic process appears to be similar in small intestinal adenocarcinomas and malignant ampullary tumours.

[Pathogenesis and histomorphology of ampullary carcinomas and their precursor lesions. Review and individual findings]

Most adenomas and carcinomas of small intestine and extrahepatic bile ducts arise in the region of Vater's papilla. In FAP it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis in an early tumor stage. In about 80% curative intended resection is possible. Operability is the most relevant prognostic factor. Inflammatory changes, fibrosis, regeneratory changes after endoscopic manipulation, hyperplasia, preneoplastic lesions close to carcinoma, deeply sited carcinomas under protruded, non-neoplastic duodenal mucosa make the diagnosis difficult on biopsy material. Histologically, intestinal type adenocarcinoma, pancreatobiliary type adenocarcinoma, undifferentiated carcinomas and unusual types can be differentiated. In our own series comprising 45 resected ampullary carcinomas 6 from 10 intestinal type adenocarcinomas, and 4 carcinomas of unusual types expressed the immunohistochemical marker profile of intestinal mucosa (keratin 7-, keratin 20+, MUC2+). 17 from 21 pancreatobiliary type adenocarcinomas, 4 undifferentiated carcinomas, as well as 3 papillary carcinomas showed the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20-, MUC2-). 3 invasive carcinomas which were negative for these markers, showed one of these characteristic marker-combinations in non-invasive adenomatous parts. These findings support the concept of histogenetically different ampullary carcinomas which are developing from the intestinal or from the pancreaticobiliary type mucosa of Vater's papilla. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear in different frequencies. In future studies molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. The histologic classification should reflect consequently the histogenesis of ampullary tumors from the two different types of papillary mucosa.

Histological evaluation of preoperative biopsies from ampulla vateri

Frequency of the lesions of the papilla Vateri is increasing in Hungary because of epidemiological reasons. Over two years nearly 300 ampullary endoscopic biopsies were taken in our hospital. In 36 percent of the patients the papillary specimens demonstrated acute or chronic inflammation, in 44 percent adenoma, including 5 percent with severe dysplasia, in 5 percent adenomatous hyperplasia and in 7 percent adenomyosis or other benign tumors (2%) were found. Around 7 percent of the ampullary samples proved to be malignant, but only in 2.6 percent were the malignancy of intraampullary origin. Nearly 25 percent of biopsies were repeated once and 10 percent twice or more. Concordance of endoscopic and pathologic diagnoses was 69 percent on average but it increased to 83 percent after including repeated biopsies. In the adenoma-carcinoma group the concordance was 90 percent. The sensitivity of the pathological diagnosis with forceps biopsy was only 77 percent, but it became at least 86 percent following papillectomy. In order to improve diagnostic reliability more extensive use of papillectomy is proposed with close cooperation between the endoscopist and pathologist.

Significance of thymidine phosphorylase/platelet-derived endothelial cell growth factor in carcinoma of the papilla of Vater

The expression of thymidine phosphorylase (TP) in carcinoma of the papilla of Vater was studied to clarify its significance in tumor progression and in determining prognosis. Fifty-nine cases of surgically resected carcinoma of the papilla of Vater were studied. Immunohistochemical staining was performed to evaluate the expression of TP, microvessel count and p53 overexpression. TP expression was demonstrated in tumor cells in 62.7% (37/59) of the cases. A higher frequency of regional lymph node metastasis was found in TP-positive tumors than in TP-negative tumors (P = 0.006). TP-positive tumors were more advanced than TP-negative tumors with regard to clinical stage (P = 0.035). TP-positive tumors had significantly higher microvessel density (27.6 +/- 10.1) than TP-negative tumors (20.4 +/- 10.0, P = 0.01). Moreover, TP expression was significantly correlated with a poor prognosis (P = 0. 02). These suggest that in carcinoma of the papilla of Vater, TP production by tumor cells is correlated with tumor progression through its regulatory effect on neovascularization.