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

Ampulla of Vater carcinoma: advancement in the relationships between histological subtypes, molecular features, and clinical outcomes

The incidence of ampulla of Vater carcinoma, a type of periampullary cancer, has been increasing at an annual percentage rate of 0.9%. However, patients with ampulla of Vater carcinoma have quite different prognoses due to the heterogeneities of the tissue origin of this carcinoma. In addition to TNM staging, histological subtypes and molecular features of ampulla of Vater carcinoma are the key factors for predicting the clinical outcomes of patients. Fortunately, with the development of testing technology, information on the histological subtypes and molecular features of ampulla of Vater carcinoma is increasingly being analyzed in-depth. Patients with the pancreaticobiliary subtype have shorter survival times. In immunohistochemical examination, high cutoff values of positive MUC1 staining can be used to accurately predict the outcome of patients. Mutant KRAS, TP53, negative SMAD4 expression, and microsatellite stability are related to poor prognosis, while the clinical value of BRCA1/BRCA2 mutations is limited for prognosis. Testing the histological subtypes and molecular characteristics of ampulla of Vater carcinoma not only is the key to prognosis analysis but also provides extra information for targeted treatment to improve the clinical outcomes of patients.

Genome-wide CRISPR Screen Reveals RAB10 as a Synthetic Lethal Gene in Colorectal and Pancreatic Cancers Carrying SMAD4 Loss

The TGFβ signaling mediator SMAD4 is frequently mutated or deleted in colorectal and pancreatic cancers. SMAD4 acts as a tumor suppressor and its loss is associated with poorer patient outcomes. The purpose of this study was to find synthetic lethal interactions with SMAD4 deficiency to find novel therapeutic strategies for the treatment of patients with SMAD4-deficient colorectal or pancreatic cancers. Using pooled lentiviral single-guide RNA libraries, we conducted genome-wide loss-of-function screens in Cas9-expressing colorectal and pancreatic cancer cells harboring altered or wild-type SMAD4. The small GTPase protein RAB10 was identified and validated as a susceptibility gene in SMAD4-altered colorectal and pancreatic cancer cells. Rescue assays showed that RAB10 reintroduction reversed the antiproliferative effects of RAB10 knockout in SMAD4-negative cell lines. Further investigation is necessary to shed light on the mechanism by which RAB10 inhibition decreases cell proliferation of SMAD4-negative cells.

Significance

This study identified and validated RAB10 as new synthetic lethal gene with SMAD4. This was achieved by conducting a whole-genome CRISPR screens in different colorectal and pancreatic cell lines. A future RAB10 inhibitors could correspond to a new therapeutic solution for patients with cancer with SMAD4 deletion.

Molecular pathways in periampullary cancer: An overview

Molecular alterations in oncogenes and tumor suppressors in various signaling pathways are basis for personalized therapy in cancer. Periampullary carcinoma behaves differently from pancreatic carcinoma both in prognosis and outcome, therefore it needs special attention. Pancreatic cancer have higher incidence of nodal spread and perineural &lymphovascular invasion suggesting it biologically more aggressive tumor compared to periampullary cancer. Since PAC tumors consist of heterogenous tissue of origin, they might contain different mutations in tumor associated genes and other changes in tissue composition among different subgroups clubbed together. Significant progress has been made in understanding the molecular nature of PAC in the previous two decades, and a large number of mutations and other genetic changes have been identified as being responsible for the disease. This review article targets to collate and discuss the molecular evolution of PAC and their implication in its outcome. As per literature, mitogen-activated protein kinase (MAPK), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), and Wnt signaling are the most common pathways involved in PAC. Mutations in KRAS, TP53, CTNNB1, SMAD4 and APC genes were the most frequently reported. I-subtype resembles colorectal cancer while the morphology of PB-type shows close resemblance to pancreatic tumors. The frequency of driver gene mutations is higher in I-type compared to PB-type of PAC indicating I-type to be genetically more unstable. The genetic landscape of PAC obtained from WES data highlighted PI3/AKT pathway to be a primary target in I-type and RAS/RAF in PB-type.

Immunohistochemical Loss of DPC4 in Tumors With Mucinous Differentiation Arising in or Involving the Gynecologic Tract

DPC4 immunohistochemistry (IHC) is usually part of the work-up of mucinous neoplasms in the ovary where the distinction between an ovarian primary and metastatic pancreaticobiliary adenocarcinoma (PanACa) must be made. Although DPC4 IHC is lost in about 55% (46%-61%) of PanACas and typically retained in most primary ovarian mucinous neoplasms, no study has evaluated the expression of this marker in a large cohort of neoplasms arising in or involving gynecologic (GYN) organs. In this study, we retrospectively analyzed the expression of DPC4 IHC in a total of 251 tumors and lesions related to the GYN tract in which DPC4 IHC stain was performed during the initial pathology evaluation. Of these, 138 were primary GYN tumors and lesions, 31 were metastatic GYN tumors involving non-GYN sites, and 83 were metastatic non-GYN tumors involving the GYN tract. We identified 27 cases with loss of DPC4 IHC expression of which 20 cases met the inclusion criteria (i.e. clinical information was available to determine the site of tumor origin). We observed that loss of DPC4 nuclear expression was most commonly seen in tumors of endocervical origin (n=7), of which 5 were gastric-type cervical adenocarcinomas (GCxACa) and 2 were usual-type cervical adenocarcinomas, either primary or metastatic. This was followed by tumors of the pancreaticobiliary tract (n=5), ovary (n=2), and appendix (n=1). In addition, 1 gastric-type vaginal adenocarcinoma (GVaACa) also showed loss of DPC4. Our findings indicate that in female patients with mucinous neoplasms involving the ovary or other sites, with loss of DPC4 by IHC, and negative pancreaticobiliary imaging, the possibility of an occult GCx/GVaACa, and rarely an ovarian primary must be considered.

Small Bowel Epithelial Precursor Lesions: A Focus on Molecular Alterations

The wider use of gastrointestinal endoscopic procedures has led to an increased detection of small intestinal preneoplastic and neoplastic epithelial lesions, most of which are identified in the duodenum and ampullary region. Like their malignant counterparts, small intestinal glandular precursor lesions, which include adenomas and hamartomas, may arise sporadically or be associated with hereditary tumor syndromes, such as familial adenomatous polyposis, MUTYH-associated polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. In addition, dysplastic, preinvasive lesions have been observed adjacent to small bowel adenocarcinomas complicating immune-related disorders, such as celiac or Crohn’s disease. Adenomatous lesions may exhibit an intestinal-type, gastric-type, or, very rarely, serrated differentiation, related to different molecular pathogenetic mechanisms. Finally, in the background of multiple endocrine neoplasia 1 syndrome, precursor neuroendocrine growths have been described. In this review we offer a comprehensive description on the histo-molecular features of the main histotypes of small bowel epithelial precursors lesions, including: (i) sporadic adenomas (intestinal-type and gastric-type; non-ampullary and ampullary); (ii) syndromic adenomas; (iii) small bowel dysplasia in celiac and Crohn’s disease; (iv) serrated lesions; (v) hamartomatous lesions; and (vi) neuroendocrine precursor lesions.

Consequences of Mutations and Abnormal Expression of SMAD4 in Tumors and T Cells

SMAD4 is a typical tumor suppressor in the TGF-β signaling pathway. In human cancers, SMAD4 is frequently mutated and inactivated. In recent years, the consequences of mutations and inactivation of SMAD4 are gradually becoming clearer. Most of the mutations have negative consequences and reduce the chances of survival of their carriers. Loss of SMAD4 functions due to mutations or abnormal expression can suppress the inhibition of tumor growth and support the tumor progression. Functions of SMAD4 and its variants in T cells are being studied extensively, to better understand the SMAD4 functions in T cells. In this review, we mainly discuss the recently reported consequences of mutations and abnormal expression of SMAD4 in tumors, and the effects of loss, deficiency or mutation of SMAD4 and its T cells, to show the use of SMAD4 mutations in cancer diagnosis and therapeutic strategies.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Molecular Diagnostics in the Neoplasms of Small Intestine and Appendix: 2018 Update

Neoplasms of the small intestine are rare in comparison with colorectal tumors. The most common tumor types arising in the small intestine are adenocarcinomas, well-differentiated neuroendocrine tumors, gastrointestinal stromal tumors, and lymphoma. Primary appendiceal neoplasms are rare and found in less than 2% of appendectomy specimens with an incidence of approximately 1.2 cases per 100,000 people per year in the United States. This article explores molecular diagnostics in the neoplasms of small intestine and appendix.

Smad4/DPC4

Smad4 or DPC4 belongs to a family of signal transduction proteins that are phosphorylated and activated by transmembrane serine-threonine receptor kinases in response to transforming growth factor beta (TGF-β) signaling via several pathways. The gene acts as a tumour suppressor gene and inactivation of smad4/DPC4 is best recognised in pancreatic cancer. However, smad4/DPC4 is also mutated in other conditions and cancers such as juvenile polyposis syndrome with and without hereditary haemorrhagic telangiectasia, colorectal and prostate cancers.Immunohistochemistry for smad4/DPC4 protein is most useful in separating benign/reactive conditions from pancreatic cancer in needle/core biopsies. In normal and reactive states, the protein is localised to the cytoplasm and nucleus, while the protein is lost in high-grade pancreatic intraepithelial neoplasia/carcinoma in situ and pancreatic cancer.

Ampullary carcinoma-A genetic perspective

Ampulla of vater carcinoma (AVC) is a rare gastrointestinal tumour that is associated with a high mortality rate and it's often diagnosed at later stages due to lack of clinical symptoms. Early diagnosis of this condition is essential to effectively treat patients for better prognosis. A significant amount of advancement has been made in understanding the molecular nature of cancer in the past decade. A substantial number of mutations and alterations have been detected in various tumors. Despite the occurrence of AVC across the globe, the number of studies conducted on this tumor type remains low; this is largely due to its rare occurrence. Moreover, AVC tissues are complex and contain mutations in oncogenes, tumour suppressors, apoptotic proteins, cell proliferation proteins, cell signaling proteins, transcription factors, chromosomal abnormalities and cellular adhesion proteins. The frequently mutated genes included KRAS, TP53 and SMAD4 and are associated with prognosis. Several molecules of the PI3K, Wnt signaling, TGF-beta pathway and cell cycle have also been altered in AVCs. This review comprises of all the genetic mutations, associated pathways and related prognosis that are involved in AVCs from the year 1989 to 2017. This report can be used as a stepping-stone to establish biomarkers for early diagnosis of AVC and to discover molecular targets for drug therapy.

Clinical, morphologic, and immunophenotypic characteristics of ampullary carcinomas with an emphasis on SMAD4 expression

BACKGROUND

The purpose of our study was to examine the relationship between clinicopathologic variables and morphologic subtypes in ampullary carcinoma, with an emphasis on the expression of SMAD4 tumor suppressor gene.

METHODS

Sixty-three cases of ampullary carcinomas resected between 2000-2011 were included in this study. Clinical characteristics and outcome data were recorded. Tumors were classified as pancreatobiliary or intestinal type based on morphology, and immunohistochemical (IHC) studies for cytokeratin 7 (CK7), cytokeratin 20 (CK20), cytokeratin 17 (CK17), and SMAD4 were performed.

RESULTS

Forty-nine percent of the ampullary tumors were pancreatobiliary, 29% were intestinal, and 22% were other variants. Tumors with pancreatobiliary morphology showed worse overall survival than those with intestinal morphology or other variants (P=0.03). A trend for higher stage, recurrence and less survival was seen in cases with negative SMAD4 expression. In multivariate analysis, age group (≤60 vs. >60 years) and expression of CK17 were the most prognostic of survival.

CONCLUSIONS

Ampullary tumors with pancreatobiliary morphology have a worse overall survival, while negative SMAD4 expression is associated with a trend of less survival.

Smad4 inhibits cell migration via suppression of JNK activity in human pancreatic carcinoma PANC-1 cells

Smad4 is a common Smad and is a key downstream regulator of the transforming growth factor-β signaling pathway, in which Smad4 often acts as a potent tumor suppressor and functions in a highly context-dependent manner, particularly in pancreatic cancer. However, little is known regarding whether Smad4 regulates other signaling pathways involved in pancreatic cancer. The present study demonstrated that Smad4 downregulates c-Jun N-terminal kinase (JNK) activity using a Smad4 loss-of-function or gain-of-function analysis. Additionally, stable overexpression of Smad4 clearly affected the migration of human pancreatic epithelioid carcinoma PANC-1 cells, but did not affect cell growth. In addition, the present study revealed that upregulation of mitogen-activated protein kinase phosphatase-1 is required for the reduction of JNK activity by Smad4, leading to a decrease in vascular endothelial growth factor expression and inhibiting cell migration. Overall, the present findings indicate that Smad4 may suppress JNK activation and inhibit the tumor characteristics of pancreatic cancer cells.

Difficult Diagnostic Problems in Pancreatobiliary Neoplasia

CONTEXT

Many common diagnostic dilemmas are encountered in pancreatobiliary pathology, frequently resulting in uncertainty on behalf of the pathologist and referral for a second opinion.

OBJECTIVES

To review 4 common diagnostic dilemmas encountered in the practice of pancreatobiliary pathology: (1) pancreatic ductal adenocarcinoma versus chronic pancreatitis; (2) pancreatic ductal carcinoma versus adenocarcinomas arising in the ampulla and intrapancreatic common bile duct; (3) the distinction of uncommon intraductal neoplasms--intraductal oncocytic papillary neoplasm, intraductal tubulopapillary neoplasm, and intraductal acinar cell carcinoma; and (4) intrahepatic cholangiocarcinoma versus metastatic carcinoma.

DATA SOURCES

A review of pertinent literature, along with the authors' personal experience, based on institutional and consultation materials.

CONCLUSIONS

Important diagnostic features for a few challenging problems in pancreatobiliary pathology are reviewed. Careful study of the microscopic features along with awareness of differential diagnoses and diagnostic pitfalls generally allows distinction of these entities. We also highlight established and novel ancillary studies that help to arrive at an accurate diagnosis.

Expression and clinical significance of epidermal growth factor receptor and insulin-like growth factor receptor 1 in patients with ampullary adenocarcinoma

Epidermal growth factor receptor (EGFR) and insulin-like growth factor receptor 1 (IGF-1R) play important roles in cell proliferation, antiapoptosis, angiogenesis, and metastasis and have been used for targeted therapies for patients with advanced colorectal and lung cancers. However, the expression and function of EGFR and IGF-1R in ampullary adenocarcinoma (AA) have not been examined in detail. We examined the expression of EGFR and IGF-1R in 106 AA patients at our institution using tissue microarrays and immunohistochemistry. The results were correlated with the clinicopathological parameters and survival. Overexpression of EGFR and IGF-1R was detected in 18 (17%) and 26 (25%) of AAs, respectively. Patients with EGFR-high tumors had shorter overall survival (mean, 109.8 ± 22.3 months) than those patients whose tumors were EGFR-low in overall study population (mean, 164.2 ± 10.6 months; P = .04). Overexpression of EGFR correlated with poor overall survival in patients with intestinal-type AA (P = .01) but not in those with pancreaticobiliary-type AAs (P = .47). In multivariate analysis, EGFR overexpression was an independent prognostic factor for overall survival (P = .02). In addition, we found that overexpression of IGF-1R correlated with AAs of pancreaticobiliary histology. No additional correlation between the expression of EGFR or IGF-1R and other clinicopathological factors was observed in our patient population. Our study demonstrates that EGFR and IGF-1R appear to be overexpressed in a subset of AAs and that strong membranous expression of EGFR is an independent predictor for overall survival in patients with AA. EGFR and IGF-1R represent potential therapeutic targets for treatment of patient with AAs.

Distribution and pathological features of pancreatic, ampullary, biliary and duodenal cancers resected with pancreaticoduodenectomy

BACKGROUND

Pancreatic cancer (PC) has the worst survival of all periampullary cancers. This may relate to histopathological differences between pancreatic cancers and other periampullary cancers. Our aim was to examine the distribution and histopathologic features of pancreatic, ampullary, biliary and duodenal cancers resected with a pancreaticoduodenectomy (PD) and to examine local trends of periampullary cancers resected with a PD.

METHODS

A retrospective review of PD between January 2000 and December 2012 at a public metropolitan database was performed. The institutional ethics committee approved this study.

RESULTS

There were 142 PDs during the study period, of which 70 cases were pre-2010 and 72 post-2010, corresponding to a recent increase in the number of cases. Of the 142 cases, 116 were for periampullary cancers. There were also proportionately more PD for PC (26/60, 43% pre-2010 vs 39/56, 70% post-2010, P = 0.005). There were 65/116 (56%) pancreatic, 29/116 (25%), ampullary, 17/116 (15%) biliary and 5/116 (4%) duodenal cancers. Nodal involvement occurred more frequently in PC (78%) compared to ampullary (59%), biliary (47%) and duodenal cancers (20%), P = 0.002. Perineural invasion was also more frequent in PC (74%) compared to ampullary (34%), biliary (59%) and duodenal cancers (20%), P = 0.002. Microvascular invasion was seen in 57% pancreatic, 38% ampullary, 41% biliary and 20% duodenal cancers, P = 0.222. Overall, clear margins (R0) were achieved in fewer PC 41/65 (63%) compared to ampullary 27/29 (93%; P = 0.003) and biliary cancers 16/17 (94%; P = 0.014).

CONCLUSIONS

This study highlights that almost half of PD was performed for cancers other than PC, mainly ampullary and biliary cancers. The volume of PD has increased in recent years with an increased proportion being for PC. PC had higher rates of nodal and perineural invasion compared to ampullary, biliary and duodenal cancers.

Cancer of the ampulla of vater: current evaluation and therapy

Ampullary cancer is a relatively rare cancer of the digestive tract. In contrast to pancreatic cancer, ampullary cancer is often curable if detected at an early stage. The evaluation and management of ampullary cancer is similar to, but distinct from, that of other pancreaticobiliary tumors. This manuscript will review the current evaluation, diagnosis, and therapy of patients with ampullary cancer. The diagnosis of ampullary cancer is complicated by its similar clinical presentation to pancreatic cancer as well as its nonspecific laboratory findings. Diagnostic modalities such as ERCP, EUS, and biopsy are necessary for differentiating the 2 cancers, and noninvasive imaging techniques such as MRI and CT may be used for tumor staging. Although pancreaticoduodenectomy is considered the primary curative surgical option, consensus guidelines regarding adjuvant and neoadjuvant chemoradiation therapies are lacking.

Aberrant expression of p53, p21, cyclin D1, and Bcl2 and their clinicopathological correlation in ampullary adenocarcinoma

Previous studies on the molecular alterations in ampullary adenocarcinoma (AA) are limited, and little is known about their clinical implications. The objective of this study is to examine the expression of p53, p21, cyclin D1, and Bcl2 and their clinical significance in patients with AA. Tissue microarrays were constructed using archival tissue from 92 patients with AA who underwent pancreaticoduodenectomy at our institution. Each tumor was sampled in triplicate with a 1.0-mm punch from representative areas. The expression of p53, p21, cyclin D1, and Bcl2 was evaluated by immunohistochemistry, and the staining results were correlated with clinicopathological features and survival. Among 92 cases studied, overexpression of p53, p21, cyclin D1, and Bcl2 was observed in 58.7%, 39.2%, 71.7%, and 5.4% of tumors, respectively. Patients whose tumor showed high level of cyclin D1 expression had higher risk of disease recurrence (P = .02) and worse recurrence-free and overall survivals after pancreaticoduodenectomy than did those with no or low cyclin D1 expression (P = .027 and P = .02, respectively). In multivariate analysis, cyclin D1 expression was an independent prognostic factor for both recurrence-free and overall survival (P < .05). However, there was no significant correlation between p53, p21, or Bcl2 expression and survival (P > .05). Our study showed that p53, p21, and cyclin D1, but not Bcl2, are frequently overexpressed in AAs. Cyclin D1 overexpression is associated with increased risk of disease recurrence and worse survival in patients with AA after resection.

The expression of PTEN is associated with improved prognosis in patients with ampullary adenocarcinoma after pancreaticoduodenectomy

CONTEXT

Phosphatase and tensin homolog (PTEN) is one of the most frequently inactivated tumor suppressor genes in sporadic cancers. Somatic mutations of PTEN occur in many tumors including those of the gastrointestinal and hepatobiliary tracts. Loss of PTEN expression is associated with poor prognosis in patients with metastatic colonic adenocarcinoma, gastroesophageal junction adenocarcinoma, gastric adenocarcinoma, and pancreatic ductal adenocarcinoma.

OBJECTIVE

To study the expression of PTEN and its significance in ampullary adenocarcinoma (AA).

DESIGN

We constructed tissue microarrays by using archival tissue from 92 patients (55 males, 37 females; median age, 63 years; age range, 37 to 87 years) with previously untreated AA who underwent pancreaticoduodenectomy at our institution. PTEN expression was evaluated by immunohistochemistry, scored semiquantitatively (based on staining intensity and percentage positive tumor cells), and correlated with clinicopathologic features and survival.

RESULTS

Of 92 cases, 23 (25.0%) were PTEN negative. Loss of PTEN expression correlated with lymph node metastasis (P = .004), advanced American Joint Committee on Cancer (AJCC) stage (P = .02), and higher frequency of recurrence (P = .03). Patients with PTEN-negative tumors had shorter disease-free survival (DFS, mean: 89.0 ± 20.8 months) and overall survival (OS, mean: 93.1 ± 19.1 months) than those with PTEN-positive tumors (DFS, mean: 161.4 ± 11.7 months, P = .01; OS, mean: 175.4 ± 11.0 months, P = .001). In multivariate analyses, PTEN expression was a prognostic factor for both DFS and OS, independent of AJCC stage, lymph node status, pathologic tumor (pT) stage, and differentiation.

CONCLUSIONS

Loss of PTEN expression is associated with poor DFS and OS in patients with AA after curative surgery. PTEN expression may be used as a prognostic marker for patients with resected AA.

MicroRNA profiling in periampullary carcinoma

BACKGROUND

MicroRNA expression patterns in many physiological and oncogenic processes have been established. However, the role of aberrant miRNA expression in periampullary carcinoma (PAC) has not been elucidated. We hypothesize that PAC may have differential expression of miRNAs which may differentiate the tumor histological subtypes.

METHODS

Fresh paired tumor and control samples were collected from the PAC patients undergoing Whipple's pancreaticoduodenectomy. Microarray miRNA profiling was performed utilizing tumor (n = 40) and control tissues; adjacent normal pancreas (n = 22), six each distal CBD, duodenum and ampulla. Data obtained was subjected to statistical and bioinformatic analysis. Differentially expressed miRNAs obtained were validated using qPCR in an independent set of samples.

RESULTS

Comparison of PAC tissue samples with controls revealed 29 common and differentially expressed miRNAs (20 upregulated and 9 downregulated) with a higher statistical significance (p < 0.001) and fold change (log2 FC > 1.5). A subset of 16 miRNAs (15 overexpressed and 1 underexpressed) differed in expression levels between pancreatobiliary and intestinal subtypes. Among these, miR-375, miR-31 and miR-196a expressions varied significantly between histological subtypes. Differential expression profiles of miRNAs specific to TNM staging was also observed in PAC subtypes. Target gene prediction for the differentially expressed miRNAs in PAC revealed that target genes are enriched for certain pathways. Particularly, Wnt signaling pathway genes appear to be relevant targets for most of the differentially expressed miRNAs.

CONCLUSION

Differentially expressed common miRNA signatures identified in PAC subgroups may have a role in pathogenesis of PAC and miR-375, miR-31 and miR-196a expression patterns may differentiate PAC subtypes.

DPC4 expression in the small intestinal adenocarcinomas

Background

Small intestinal adenocarcinomas (SACs) are rare malignancies of the alimentary tract with uncertain carcinogenesis.

Methods

We investigated the expression of deleted in pancreatic cancer 4 (DPC4) in 188 cases of surgically resected SACs, using tissue microarray technology.

Results

Twenty-four of the 188 tumors showed complete loss of Smad4/DPC4 expression in cytoplasm (score, 0; 12.8%). Eighty-four and 31 cases were moderately and strongly positive, respectively (score, 2 and 3; 44.7% and 16.5%, respectively) and 49 cases were focally or weakly stained (score, 1; 29.1%). Immunohistochemistry analysis showed that the expression of Smad4/DPC4 was related to an increased risk of lymphatic invasion but not to other clinicopathological features of the tumors (tumor location, differentiation, growth pattern, T stage, direct invasion, vascular invasion, and nodal metastasis). There was no significant association between Smad4/DPC4 expression and patient survival.

Conclusions

The present research is the first study to evaluate Smad4/DPC4 expression in a large sample of SACs with clinicopathologic correlation. Future studies should focus on the immunohistochemical and molecular characteristics of SACs to clarify their tumorigenesis.

[Tumors of Vater's ampulla]

Tumors of Vater's ampulla are generally uncommon. In this location intestinal type adenomas are frequently found, followed by noninvasive papillary neoplasms of the pancreaticobiliary type and neuroendocrine tumors (carcinoids). Carcinomas of Vater's ampulla represent about 0.5% of all gastrointestinal malignancies. Intestinal type adenocarcinoma is the most common malignant epithelial tumor followed by the pancreaticobiliary type adenocarcinoma. Highly malignant neuroendocrine carcinomas of Vater's ampulla are very uncommon. Carcinomas of the ampullary region can be sporadic or a component of several disease syndromes. Designation of large carcinomas as tumors with an ampullary or extra-ampullary origin can be difficult but is of relevance for a TNM conform classification. Helpful in the decision are the relationship between the tumor centre and Vater's ampulla, the existence of premalignant lesions in the ampullary epithelium as well as histology and immunostaining of the tumor.

Angiogenesis: a prognostic determinant in pancreatic cancer?

Angiogenesis has been associated with disease progression in many solid tumours, however the statement that tumours need angiogenesis to grow, invade and metastasise seems no longer applicable to all tumours or to all tumour subtypes. Prognostic studies in pancreatic cancer are conflicting. In fact, pancreatic cancer has been suggested an example of a tumour in which angiogenesis is less essential for tumour progression. The aim of the present study was therefore to measure angiogenesis in two anatomically closely related however prognostically different types of pancreatic cancer, pancreatic head and periampullary cancer, and investigate its relation with outcome. Vessels were stained by CD31 on original paraffin embedded tissue from 206 patients with microscopic radical resection (R0) of pancreatic head (n=98) or periampullary cancer (n=108). Angiogenesis was quantified by microvessel density (MVD) and measured by computerised image analysis of three randomly selected fields and investigated for associations with recurrence free survival (RFS), cancer specific survival (CSS), overall survival (OS) and conventional prognostic factors. MVD was heterogeneous both between and within tumours. A higher MVD was observed in periampullary cancers compared with pancreatic head cancers (p<.01). Furthermore, MVD was associated with lymph node involvement in pancreatic head (p=.014), but not in periampullary cancer (p=.55). Interestingly, MVD was not associated with RFS, CSS or with OS. In conclusion, angiogenesis is higher in periampullary cancer and although associated with nodal involvement in pancreatic head cancer, pancreatic cancer prognosis seems indeed angiogenesis independent.

Clinicopathologic analysis of ampullary neoplasms in 450 patients: implications for surgical strategy and long-term prognosis

BACKGROUND

Whether ampullary neoplasms are best surgically managed by pancreaticoduodenectomy versus local ampullectomy is controversial. We sought to examine the outcome of patients undergoing pancreaticoduodenectomy versus ampullectomy, as well as to identify factors predictive of lymph node metastasis in patients with ampullary neoplasms.

METHODS

Between 1970 and 2007, 450 patients who underwent surgical resection of ampullary adenoma or adenocarcinoma were identified from a prospective, single-institution database. Data on clinicopathologic factors, morbidity, mortality, and survival were analyzed.

RESULTS

The initial surgical procedure was pancreaticoduodenectomy in 96.7% patients and ampullectomy in 3.3%. Final diagnosis was invasive adenocarcinoma (77.1%) or adenoma (22.9%). Median tumor size was similar for adenomas associated with an adenocarcinoma (2.5 cm) versus adenomas without invasive cancer (2.9 cm; P=0.71). Morbidity was comparable with pancreaticoduodenectomy (52.2%) versus ampullectomy (33.3%; P=0.15), as was 30-day mortality (pancreaticoduodenectomy, 2.1% versus ampullectomy, 0%; P=0.6). Metastatic disease to regional lymph nodes was present in 54.5% patients with adenocarcinoma. Factors associated with presence of lymph node metastasis included tumor size > or = 1 cm (OR 2.1), poor histologicgrade (OR 4.8), perineural invasion (OR 3.0), microscopic vessel invasion (OR 6.6), and depth of invasion > pT1 (OR 4.3; all P<0.05). Specifically, risk of lymph node metastasis increased with T stage (T1, 28.0%; T2, 50.9%; T3, 71.7%; T4, 77.3%; P<0.001).

CONCLUSION

When surgery is indicated, radical resection is required for early invasive adenocarcinoma of the ampulla of Vater, as lymph node metastases are present in nearly 30% of patients with T1 disease. Pancreaticoduodenectomy should be the preferred approach for most ampullary neoplasms that require surgical resection.

Clinicopathologic analysis of ampullary neoplasms in 450 patients: implications for surgical strategy and long-term prognosis

BACKGROUND

Whether ampullary neoplasms are best surgically managed by pancreaticoduodenectomy versus local ampullectomy is controversial. We sought to examine the outcome of patients undergoing pancreaticoduodenectomy versus ampullectomy, as well as to identify factors predictive of lymph node metastasis in patients with ampullary neoplasms.

METHODS

Between 1970 and 2007, 450 patients who underwent surgical resection of ampullary adenoma or adenocarcinoma were identified from a prospective, single-institution database. Data on clinicopathologic factors, morbidity, mortality, and survival were analyzed.

RESULTS

The initial surgical procedure was pancreaticoduodenectomy in 96.7% patients and ampullectomy in 3.3%. Final diagnosis was invasive adenocarcinoma (77.1%) or adenoma (22.9%). Median tumor size was similar for adenomas associated with an adenocarcinoma (2.5 cm) versus adenomas without invasive cancer (2.9 cm; P=0.71). Morbidity was comparable with pancreaticoduodenectomy (52.2%) versus ampullectomy (33.3%; P=0.15), as was 30-day mortality (pancreaticoduodenectomy, 2.1% versus ampullectomy, 0%; P=0.6). Metastatic disease to regional lymph nodes was present in 54.5% patients with adenocarcinoma. Factors associated with presence of lymph node metastasis included tumor size > or = 1 cm (OR 2.1), poor histologicgrade (OR 4.8), perineural invasion (OR 3.0), microscopic vessel invasion (OR 6.6), and depth of invasion > pT1 (OR 4.3; all P<0.05). Specifically, risk of lymph node metastasis increased with T stage (T1, 28.0%; T2, 50.9%; T3, 71.7%; T4, 77.3%; P<0.001).

CONCLUSION

When surgery is indicated, radical resection is required for early invasive adenocarcinoma of the ampulla of Vater, as lymph node metastases are present in nearly 30% of patients with T1 disease. Pancreaticoduodenectomy should be the preferred approach for most ampullary neoplasms that require surgical resection.

Survival analysis after pancreatic resection for ampullary and pancreatic head carcinoma: an analysis of clinicopathological factors

BACKGROUND AND OBJECTIVES

Surgery remains the only curative option for the treatment of pancreatic and ampullary carcinomas. To examine the survival differences between ampullary and pancreatic head carcinomas after pancreaticoduodenectomy.

METHODS

A retrospective review of patients with ampullary or pancreatic head adenocarcinoma undergoing curative resection during a 6-year period prior to 2000.

RESULTS

A total of 104 patients underwent pancreaticoduodenectomy for pancreatic head and ampullary carcinomas (n = 65 and n = 39, respectively). Histologically, pancreatic cancer was worse, with more lymph node involvement and more positive resection margins and vascular and perineural invasions than found in ampullary carcinoma. The median disease-free and overall survival rates were significantly better for ampullary cancer when compared with pancreatic cancer (17 vs. 9 months [P = 0.001] and 35 vs. 24 months [P = 0.006], respectively). The actuarial 5-year disease-free and overall survival rates were 4.4% and 10.5%, respectively, for pancreatic carcinoma and 27.9% and 31.8%, respectively, for ampullary carcinoma. Multivariate analysis showed that microscopic resection margin involvement (P = 0.02) and involvement of over three nodes (P < 0.001) were significant factors affecting the overall survival for pancreatic and ampullary carcinomas, respectively.

CONCLUSIONS

In this study, patients with ampullary carcinoma have a better prognosis and survival than those with pancreatic carcinoma.

Smad4-mediated TGF-beta signaling in tumorigenesis

Transforming growth factor-β (TGF-β) family members exert their function via specific type I and type II serine/threonine kinase receptors and intracellular Smad transcription factors, including the common mediator Smad4. The dual effects of TGF-β signaling on tumor initiation and progression are cell-specific and yet to be determined under distinct contexts. A number of genetically manipulated mouse models with alterations in the TGF-β pathway genes, particularly the pivotal Smad4, revealed that these genes play crucial functions in maintaining tissue homeostasis and suppressing tumorigenesis. Loss of Smad4 plays a causal role in initiating squamous cell carcinomas of skin and upper digestive tract as well as adenocarcinomas of gastrointestinal tract. However, for some cancers like pancreatic and cholangiocellular carcinomas, Smad4 deficiency does not initiate the tumorigenesis but acts as a promoter to accelerate or synergize the development and progression of cancers that are started by other oncogenic pathways. Intriguingly, emerging evidences from mouse models have highlighted the important roles of non-cell autonomous effects of Smad4-mediated TGF-β signaling in the inhibition of oncogenesis. All these data have greatly deepened our understanding of molecular mechanisms of cell-autonomous and non-cell autonomous effect of Smad4-mediated TGF-β signaling in suppressing carcinogenesis, which may facilitate the development of successful therapies targeting TGF-β signaling for the treatment of human cancers.

Molecular analysis of PIK3CA, BRAF, and RAS oncogenes in periampullary and ampullary adenomas and carcinomas

BACKGROUND

Mutations of KRAS are known to occur in periampullary and ampullary adenomas and carcinomas. However, nothing is known about NRAS, HRAS, BRAF, and PIK3CA mutations in these tumors. While oncogenic BRAF contributes to the tumorigenesis of both pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasms/carcinomas (IPMN/IPMC), PIK3CA mutations were only detected in IPMN/IPMC. This study aimed to elucidate possible roles of BRAF and PIK3CA in the development of ampullary and periampullary adenomas and carcinomas.

METHODS

Mutations of BRAF, NRAS, HRAS, KRAS, and PIK3CA were evaluated in seven adenomas, seven adenomas with carcinoma in situ, and 21 adenocarcinomas of the periampullary duodenal region and the ampulla of Vater. Exons 1 of KRAS; 2 and 3 of NRAS and HRAS; 5, 11, and 15 of BRAF; and 9 and 20 of PIK3CA were examined by direct genomic sequencing.

RESULTS

In total, we identified ten (28.6%) KRAS mutations in exon 1 (nine in codon 12 and one in codon 13), two missense mutations of BRAF (6%), one within exon 11 (G469A), and one V600E hot spot mutation in exon 15 of BRAF. BRAF mutations were present in two of five periampullary tumors. All mutations appear to be somatic since the same alterations were not detected in the corresponding normal tissues.

CONCLUSION

Our data provide evidence that oncogenic properties of KRAS and BRAF but not NRAS, HRAS, and PIK3CA contribute to the tumorigenesis of periampullary and ampullary tumors; BRAF mutations occur more frequently in periampullary than ampullary neoplasms.

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.

Double immunohistochemical staining with MUC4/p53 is useful in the distinction of pancreatic adenocarcinoma from chronic pancreatitis: a tissue microarray-based study

CONTEXT

Immunohistochemical stains have been used for the distinction of pancreatic adenocarcinoma from chronic pancreatitis.

OBJECTIVE

To determine if a double stain for MUC/p53 improved specificity and sensitivity for distinction of pancreatic adenocarcinoma from chronic pancreatitis by comparing maspin, mucin 4 (MUC4), p53, Smad4, and the double stain MUC4/p53.

DESIGN

Seventy-four pancreatic adenocarcinomas and 19 chronic pancreatitis cases were retrieved from archival files. Tissue cores were arrayed to create a tissue microarray of 2-mm cores. Sections were stained with antibodies against maspin, MUC4, p53, and Smad4. Additionally, a 2-color, double stain for MUC4 and p53 was developed and evaluated. Five percent or greater staining in either of the cores was considered positive. Intensity (0, 1, 2) and extent (%) of tumor cells staining was also determined.

RESULTS

The sensitivity for distinction of pancreatic adenocarcinoma from chronic pancreatitis with maspin, MUC4, p53, and Smad4 was 90%, 77%, 60%, and 63%, respectively; the specificity was 67%, 78%, 88%, and 88%, respectively. When MUC4 and p53 were combined in a double stain, and positive staining for either considered a positive result, the sensitivity increased to 96% but specificity was 73%. When immunoreactivity for both antibodies was necessary for a positive result, sensitivity fell to 39% but specificity was 100%. No correlation was found between intensity or extent of staining with any of the individual stains and tumor differentiation.

CONCLUSION

The double immunohistochemical stain for MUC4/p53 can be a useful diagnostic tool in conjunction with the hematoxylin-eosin-stained section for pancreatic adenocarcinoma, particularly when limited tumor is available for multiple stains.

Effect of DPC4 gene on invasion and metastasis of colorectal carcinoma cells

To investigate the effect of DPC4 gene on invasion and metastasis of colorectal carcinoma cells, the expression of DPC4 was detected in sixty-three samples of colorectal tumors and seven cases of colorectal mucosa. The biological behavior of tumors expressing DPC4 was evaluated (including tumor staging, differentiation degree and metastasis). pcDNA3.1-DPC4 plasmid was constructed and transferred into HCT116 cells not expressing DPC4. The cell models (DPC4(+)-HCT116) steadily expressing DPC4 were obtained. Compared with HCT116 and pcDNA3.1-HCT116 cells, the doubling time of DPC4(+)-HCT116 cells was lengthened obviously (P<0.01), the apoptosis rate of DPC4(+)-HCT116 cells was significantly increased (PP<0.01), the cloning efficiency, cell adherency, migration and invasion ability of DPC4+-HCT116 cells were dropped obviously (P<0.01). The number of cancer nodules was decreased significantly in abdominal cavity and liver of the nude mice inoculated with DPC4(+)-HCT116 cells. The activity of MMP-9 and MMP-2 was detected by gelatin zymography. In comparison with HCT116 and pcDNA3.1-HCT116 cells, the activity of MMP-9 was decreased in DPC4(+)-HCT116 cells. Therefore, the down-regulation of DPC4 expression may be associated with the carcinogenesis of colorectal carcinoma. DPC4 may inhibit the proliferation of colon cancer cell by restraining growth and inducing apoptosis, and the invasion and metastasis of colorectal carcinoma cells. MMP-9 may be one of the downstream target genes regulated by DPC4.

Expression of DPC4/Smad4 gene in stone-containing intrahepatic bile duct

BACKGROUND AND OBJECTIVES

Hepatolithiasis is etiologically related to cholangiocarcinoma. We underwent this study with an attempt to examine the expression of DPC4/Smad4 gene in stone-containing intrahepatic bile ducts (IHD) and intrahepatic cholangiocarcinoma (ICC).

PATIENTS AND METHODS

The immunohistochemical method and RT-PCR analysis were used to study the expression of DPC4/Smad4 gene in normal IHD, stone-containing IHD, and ICC. All the specimens were from hepatic resection.

RESULTS

The immunohistochemical study showed that all specimens from 24 normal IHD had marked expression of DPC4/Smad4 gene, while there was 4.4% (2/46) and 33.3% (3/9) loss of DPC4/Smad4 expression in stone-containing IHD and ICC, respectively. Among the specimens of stone-containing IHD, all the hyperplastic epithelial cells showed normal expression of DPC4/Smad4 gene while dysplastic epithelial cells showed 20% (2/10) loss expression of DPC4/Smad4. The RT-PCR analysis showed that the normal IHD had the highest content of DPC4/Smad4 mRNA, which was threefold and sixfold higher than that of stone-containing IHD and ICC, respectively.

CONCLUSION

Loss expression of DPC4/Smad4 gene was found both in stone-containing IHD and ICC. Dysplastic epithelium of stone-containing IHD had higher potential for malignant transformation.

High-Grade Neuroendocrine Carcinoma of the Ampulla of Vater

We describe the clinical and pathologic features of 14 cases of high-grade neuroendocrine carcinoma (HGNEC) of the ampulla of Vater classified according to WHO classification of lung tumors into small cell carcinoma (SCC, 6 cases) and large cell neuroendocrine carcinoma (LCNEC, 8 cases) types. The immunohistochemical findings were compared with those of 13 cases of primary poorly differentiated ampullary adenocarcinomas (PDACA) lacking neuroendocrine morphology. The mean age of 10 males and 4 females was 70 years. The mean tumor size was 2.5 cm. Ten of 13 patients had lymph node metastases (mean, 2.3 nodes involved). Documented sites of distant metastases included brain and liver. Overall, 64% of patients with ampullary HGNEC died of disease (mean follow-up, 14.5 months). Four patients had no evidence of disease after resection (mean, 20 months). Half of the tumors were associated with adenomas of the adjacent mucosa, 2 with high-grade dysplasia. Two HGNECs were combined with a conventional adenocarcinoma and another with a squamous cell carcinoma component. By immunohistochemistry, the HGNECs were positive for cytokeratins (AE1/AE3, 100%; Cam5.2, 67%; CK7, 87%; CK20, 38%), similar to the pattern found in PDACAs. p27 expression was lost in 1 case of HGNEC and in all PDACAs. Retinoblastoma (Rb) protein expression was lost in 60% of HGNECs and in none of the PDACA cases. In conclusion, HGNECs of the ampulla are rare (2%-3% of ampullary tumors in our material). The clinical course parallels that of their pulmonary counterparts and appears to be worse than that of locally advanced ampullary adenocarcinomas. The association with adenoma and or conventional adenocarcinoma components may suggest a common pathway in the initial carcinogenesis of these two types of tumors. Loss of Rb expression, a characteristic finding in pulmonary SCCs, is present in almost half of ampullary HGNECs. In contrast, p27 expression is lost in PDACAs and retained in most HGNECs. Thus, there are differences in the molecular phenotypes of these two types of ampullary carcinoma, supporting the distinction of poorly differentiated carcinomas with a neuroendocrine phenotype from those without.

Effect of deleted pancreatic cancer locus 4 gene transfection on biological behaviors of human colorectal carcinoma cells

AIM: To investigate the effect of deleted pancreatic cancer locus 4 (DPC4) gene transfection on biological behaviors of human colorectal carcinoma cells and the role of DPC4 gene in colorectal carcinogenesis.

METHODS: PcDNA3.1-DPC4 plasmid was re-constructed by gene-recombination technology. SW620 cells, a human colorectal carcinoma cell line, were transfected with PcDNA3.1-DPC4 plasmid using lipofectamine transfecting technique. Transfected cells were selected with G418. Expression of Smad4 protein was detected in cells transfected with DPC4 gene by immunohistochemistry and Western blot. Biological characteristics of transfected cells were evaluated by population-doubling time and cloning efficiency. Alterations of percentage of S phage cells (S%) and apoptosis rate were determined by flow- cytometry.

RESULTS: PcDNA3.1-DPC4 plasmid was constructed successfully. SW620 cells transfected with PcDNA3.1-DPC4 plasmid (DPC4⁺-SW620 cells) showed a strong intracellular expression of Smad4 protein, and the positive signal was localized in cytoplasm and nuclei, mainly in cytoplasm, where the expressions of Smad4 protein in SW620 cells transfected with PcDNA3.1 plasmid (PcDNA3.1-SW620 cells) and non-transfected SW620 cells (SW620 cells) were weaker than those in DPC4⁺-SW620 cells. The population- doubling time in DPC4⁺-SW620 cells (116 h) was significantly longer than that in SW620 cells (31 h) and PcDNA3.1-Sw620 cells (29 h) (P<0.01). The cloning efficiencies of DPC4⁺-SW620 cells (12%) were markedly lower than those of SW620 cells (69%) and PcDNA3.1-Sw620 cells (67%) (P<0.01). Compared with SW620 cells and PcDNA3.1-Sw620 cells, the G₀-G₁% of DPC4⁺-SW620 cells was obviously higher and the S% was markedly lower (P<0.05). Apoptosis rate of DPC4⁺-SW620 cells was significantly higher than that of SW620 cells and PcDNA3.1-SW620 cells.

CONCLUSION: PcDNA3.1-DPC4 plasmid can be successfully re-constructed and stably transfected into human SW620 cells, thereby the cells can steadily express Smad4. DPC4 protein may regulate proliferation of colorectal carcinoma cells by inhibiting cell growth and inducing cell apoptosis.

Factors of transforming growth factor beta signalling are co-regulated in human hepatocellular carcinoma

Transforming growth factor beta (TGFbeta) is a central mitoinhibitory factor for epithelial cells, and alterations of TGFbeta signalling have been demonstrated in many different human cancers. We have analysed human hepatocellular carcinomas (HCCs) for potential pro-tumourigenic alterations in regard to expression of Smad4 and mutations and expression changes of the pro-oncogenic transcriptional co-repressors Ski and SnoN, as well as mRNA levels of matrix metalloproteinase-2 (MMP2), which is transcriptionally regulated by TGFbeta. Smad4 mRNA was detected in all HCCs; while, using immunohistology, loss of Smad4 expression was found in 10% of HCCs. Neither mutations in the transformation-relevant sequences nor significant pro-tumourigenic expression changes of the Ski and SnoN genes were detected. In HCC cell lines, expression of both genes was regulated, potentially involving phosphorylation. Ski showed a distinct nuclear speckled pattern, indicating recruitment to active transcription complexes. MMP2 mRNA levels were increased in 19% of HCCs, whereas MMP2 mRNA was not detectable in HCC cell lines, suggesting that MMP2 was derived only from tumour stroma cells. Transcript levels of Smad4, Ski, SnoN and MMP2 correlated well. These data argue against a significant role of Ski and SnoN in human hepatocarcinogenesis and suggest that, in the majority of HCCs, the analysed factors are co-regulated by an upstream mechanism, potentially by TGFbeta itself.

Utilizing Nottingham Prognostic Index in microarray gene expression profiling of breast carcinomas

We report a novel approach to gene expression profiling using the Nottingham Prognostic Index (NPI) to stratify 26 patients with invasive breast carcinoma. As an aggregate index of parameters reflecting metastatic potential, growth rate, and genetic instability the NPI has distinct advantages over other clinicopathologic features used to segregate breast cancer patients. As a continuous variable it offers a responsive and sensitive means of modeling a continuum of clinical aggressiveness. Using RNA extracted from 26 tumors and cDNA microarrays with 23 343 unique genetic elements, 84 genes and expressed sequence tags were identified whose expression patterns correlated with NPI. Differential expression by immunohistochemistry (IHC) was also observed for two of three genes evaluated by this method. Correlation was determined by the Spearman rank correlation method with null distribution analysis. Among the 84 genetic elements were seven previously implicated in neoplastic progression (including the two demonstrating differential expression by IHC), 11 without specific cancer association but localized to chromosomal sites whose loss or gain has been identified in cytogenetic studies of breast carcinoma, and 73 not previously associated with breast carcinoma. Collectively, the expression patterns of these 84 elements have potential to distinguish high and low NPI patient samples. These data add support to the assertion that prognostic groups of breast carcinoma are reflected in distinguishable expression profiles of a limited set of genes.

Expression and significance of Smad4 in colorectal carcinoma tissue

AIM: To investigate the role of Smad4 protein in colorectal carcinogenesis.

METHODS: Expression of Smad4 was detected in 70 cases of normal tissues and colorectal tumor by a streptavidin-peroxidase conjugation method (S-P).

RESULTS: Smad4 expression was significantly lower in colorectal carcinoma (n = 52) than that in the normal tissues (n = 7) and was related to the tumor stages, differentiation and metastasis (lymph node or blood) (P < 0.05).

CONCLUSION: Down-regulation of Smad4 expression may be associated with the carcinogenesis, and Smad4 may play a role in invasion and metastasis of colorectal carcinoma.

The Pancreatic Duct and Its Arteriovenous Relationship

Pancreatic intraepithelial neoplasia (PanIN) may be difficult to differentiate from isolated glands of pancreatic adenocarcinoma. We studied the normal relationship between the pancreatic ducts and the pancreatic muscular blood vessels in 126 pancreata, 64 of which were removed for pancreatic adenocarcinoma and 62 for other diagnoses. We also examined the effects that atrophy and PanIN have on this relationship. In normal pancreatic parenchyma and in mild to moderate atrophy, blood vessels are guideposts of the interlobular space. The pancreatic acinar parenchyma ensheathes the pancreatic ductal system and separates it from the muscular pancreatic vasculature. Since these blood vessels do not accompany the pancreatic ducts, the presence of a well-differentiated duct-like structure, which may resemble PanIN, located adjacent to a pancreatic blood vessel should be a clue to the infiltrative and hence malignant nature of that gland. Ducts showing PanIN appear to resist atrophy. Since lobular outlines and vascular landmarks are ultimately lost in severe atrophy, they cannot be relied on to aid in the distinction between PanIN and invasive carcinoma. However, it is unusual to see PanIN1 in such severe atrophy (2%), and although the normal vascular landmarks are no longer there to aid in the interpretation, the presence of well-differentiated duct-like structures resembling PanIN1 in this background should be viewed with suspicion for well-differentiated adenocarcinoma.