Ki-ras mutations and p53 protein expressions in intrahepatic cholangiocarcinomas: relation to gross tumor morphology

Cholangiocarcinoma: molecular targeting strategies for chemoprevention and therapy

Cholangiocarcinomas are devastating cancers that are increasing in both their worldwide incidence and mortality rates. The challenges posed by these often lethal biliary tract cancers are daunting, with conventional treatment options being limited and the only hope for long-term survival being that of complete surgical resection of the tumor. Unfortunately, the vast majority of patients with cholangiocarcinoma typically seek treatment with advanced disease, and often these patients are deemed poor candidates for curative surgery. Moreover, conventional chemotherapy and radiation therapy have not been shown to be effective in prolonging long-term survival, and although photodynamic therapy combined with stenting has been reported to be effective as a palliative treatment, it is not curative. Thus, there is a real need to develop novel chemopreventive and adjuvant therapeutic strategies for cholangiocarcinoma based on exploiting select molecular targets that would impact in a significant way on clinical outcome. This review focuses on potential preventive targets in cholangiocarcinogenesis, such as inducible nitric oxide synthase, cyclooxygenase-2, and altered bile acid signaling pathways. In addition, molecular alterations related to dysregulation of cholangiocarcinoma cell growth and survival, aberrant gene expression, invasion and metastasis, and tumor microenvironment are described in the context of various clinical and pathological presentations. Moreover, an emphasis is placed on the importance of critical signaling pathways and postulated interactions, including those of ErbB-2, hepatocyte growth factor/Met, interleukin-6/glycoprotein130, cyclooxygenase-2, vascular endothelial growth factor, transforming growth factor-beta, MUC1 and MUC4, beta-catenin, telomerase, and Fas pathways as potential molecular therapeutic targets in cholangiocarcinoma.

Immunohistochemical analysis of biliary tract lesions

The distinction among inflammatory, benign, and malignant lesions of the biliary tract can at times be difficult. Several methods have been used, including immunohistochemistry (IHC), with variable success. We evaluated a panel of IHC stains to determine their utility in discriminating between bile duct lesions. Formalin-fixed, paraffin-embedded 4-microm sections from 12 inflammatory lesions, 10 bile duct adenomas, and 13 bile duct carcinomas were immunostained using a modified avidin-biotin-complex technique after epitope enhancement using antibodies for p53, Ki-67, and bcl-2. For p53 and bcl-2, greater than 1% of cells staining positive was interpreted as positive. The proliferation index was calculated by determining the number of Ki-67-positive cells in a 1000 cell count. In the inflammatory group, 0 of 12 reacted with anti-p53, 2 of 12 were positive with anti-bcl-2, and the proliferation index with was 22.9% +/- 3.9%. Two of 10 bile duct adenomas showed reactivity with anti-bcl-2, and none were decorated with anti-p53 or Ki-67. In the carcinoma group, 6 of 13 were positive with anti-p53, 9 of 12 were positive with anti-bcl-2, and the proliferation index was 35.3% +/- 5.5%. The proliferation rates differed significantly between groups (P < 0.05). The presence of bcl-2 and p53 immunoreactivity coupled with a high proliferative rate in a biliary tract lesion suggests a malignant process. A panel using these antibodies may be useful in difficult cases.

Hepatic resection of the intraductal papillary type of peripheral cholangiocarcinoma

BACKGROUND

Peripheral cholangiocarcinoma (PCC) can be grossly classified into mass-forming, periductal-infiltrating, and intraductal papillary (IP) types. Information on IP-PCC patients undergoing hepatectomy is sparse because of the small number of cases.

METHODS

The clinical features of 40 IP-PCC patients undergoing hepatectomy between 1977 and 2000 were reviewed. The clinical features of 94 PCC patients without IP growth undergoing hepatectomy were used for comparison.

RESULTS

IP-PCC and non-IP-PCC groups had similar age distributions (P =.674), sex ratios (P =.079), and positive rates for serum carcinoembryonic antigen and CA 19-9 (P =.121 and.795, respectively). The two groups also exhibited similar rates of association between hepatolithiasis and PCC (P =.230). However, more IP-PCC patients exhibited signs during admission, and more had ALT values >36 IU/L; they also had smaller tumors, more mucobilia association, and tumors in earlier stages and had undergone more postoperative chemotherapy. Multivariate logistic regression analysis showed that only ALT >36 IU/L differentiated IP-PCC from non-IP-PCC patients. The two groups exhibited similar operative mortality (P = 1.0). Follow-up ranged from 1.6 to 125.2 months (mean and median, 44.6 and 5.7 months, respectively). The 1-, 3-, and 5-year overall survival rates were 72.9%, 41.2%, and 24.7%, respectively, in the IP-PCC group and 43.3, 6.03%, and 2.01% in the non-IP-PCC group. The prognosis was favorable for the IP-PCC patients (P <.00001), particularly for IP-PCC patients who received curative hepatectomy (P =.013).

CONCLUSIONS

IP-PCC patients had significantly better survival than non-IP-PCC patients, and aggressive curative hepatic resection is associated with a longer survival.

Expression of epidermal growth factor receptor, apomucins, matrix metalloproteinases, and p53 in rat and human cholangiocarcinoma: appraisal of an animal model of cholangiocarcinoma

OBJECTIVE

We sought to determine the expression of molecular markers in an animal model of cholangiocarcinoma compared with those in human cholangiocarcinoma.

SUMMARY BACKGROUND DATA

Cholangiocarcinoma is a rare disease characterized by early intrahepatic and extrahepatic spread, which seriously limits the efficacy of surgery. Establishing an experimental model to study the cholangiocarcinogenesis is desirable.

METHODS

Sprague-Dawley rats weighing 300 +/- 50 g were used for the study group. The animals were given 0.3% thioacetamide in tap water continuously. Thirty mass-forming peripheral cholangiocarcinoma patients also were studied. Expression of epidermal growth factor receptor (EGFR), MUC1, MUC2, MUC5AC, MMP-2, MMP-9, and p53 in both human and experimental rat cholangiocarcinoma was examined using immunohistochemistry.

RESULTS

Using thioacetamide 0.3% as a hepatoxin to induce cholangiocarcinoma in rats, microfoci of cancerous cells were detected from 12 weeks, and all experimental rats displayed diffuse mass-forming cholangiocarcinoma after 24 weeks. EGFR was strongly expressed in 14 (47%) of 30 human cholangiocarcinoms and 24 (100%) of 24 rat cholangiocarcinomas, respectively. MUC1 was strongly expressed in all human and rat cholangiocarcinomas, whereas MUC2 and MUC5AC were focally and weakly expressed. MMP-2 and MMP-9 were strongly expressed in 22 (73%) of 30 human cholangiocarcinomas and 24 (100%) of 24 rat cholangiocarcinomas, respectively. p53 overexpression was detected in 9 (30%) of 30 human cholangiocarcinoma and none of the rat cholangiocarcinoma, respectively.

CONCLUSIONS

The expression of EGFR, apomucins, MMPs, and p53 in rat cholangiocarcinoma was strongly homologous to human cholangiocarcinoma. Thioacetamide-induced cholangiocarcinoma in rats provides an excellent model for investigating cholangiocarcinogenesis in vivo.

Rapid Detection of K-ras Mutations in Bile by Peptide Nucleic Acid-mediated PCR Clamping and Melting Curve Analysis: Comparison with Restriction Fragment Length Polymorphism Analysis

Background: Current methods for detection of K-ras gene mutations are time-consuming. We aimed to develop a one-step PCR technique using fluorescent hybridization probes and competing peptide nucleic acid oligomers to detect K-ras mutations in bile and to compare the efficacy with restriction fragment length polymorphism (RFLP) analysis.

Methods: Bile samples were obtained from 116 patients with biliary obstruction, including gallstones (n = 64), benign biliary strictures (n = 6), pancreatic cancer (n = 20), and cholangiocarcinoma (n = 26). The DNA was extracted and subjected to K-ras mutation analysis by real-time PCR and RFLP analysis. Mutations were confirmed by direct sequencing. The sensitivity and specificity were calculated according to the clinical results.

Results: The analysis time for real-time PCR was &lt;1 h, whereas RFLP analysis took more than 2 days. With the sensor probe designed for the GAT (G12D) mutant in codon 12 of the K-ras gene, the real-time PCR method also detected the GTT (G12V) mutant. In contrast, a specific sensor probe for the TGT (G12C) mutant detected GAT (G12D), AGT (G12S), and GTT (G12V) mutants in addition to the TGT mutant. The real-time PCR assay allowed the detection of mutation in a 3000-fold excess of wild-type bile DNA. In bile, K-ras codon 12 mutations were detected in 16 of 46 malignant cases by real-time PCR with the TGT probe and 15 by RFLP analysis. All benign cases were wild type.

Conclusion: Real-time PCR with a cysteine-specific (TGT) sensor probe can rapidly detect K-ras gene mutations in bile and diagnose malignant biliary obstruction with high specificity.

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.

Reversal of multiple drug resistance in cholangiocarcinoma by the glutathione S-transferase-pi-specific inhibitor O1-hexadecyl-gamma-glutamyl-S-benzylcysteinyl-D-phenylglycine ethylester

Cholangiocarcinoma is markedly resistant to chemotherapy and has a dismal prognosis, but its mechanism of drug resistance is unknown. This study examines whether glutathione S-transferase-pi (GSTP1-1) is involved in resistance to anticancer drugs in cholangiocarcinoma and whether GSTP1-1-specific inhibitors can overcome this resistance. First, immunohistochemical examination disclosed strong staining of all our 17 cholangiocarcinoma specimens for GSTP1-1, irrespective of histological type. Transfection of the GSTP1-1 antisense expression vector into a human cholangiocarcinoma cell line (HuCCT1) apparently decreased its intracellular GSTP1-1 concentration, and the sensitivity of transfectants to adriamycin (ADR), cisplatin, and alkylating agents such as melphalan and 4-hydroxyperoxycyclophosphamide (4-HC) was increased significantly, compared with that of mock transfectants. We next synthesized GSTP1-1-specific inhibitors by elongating the carbon chain of the ethylester at the N-terminal of gamma-glutamyl-S-benzylcysteinyl-phenylglycyl diethylester and performed a pharmacokinetic study on them. Of six GSTP1-1 inhibitors tested, O1-hexadecyl-gamma-glutamyl-S-benzylcysteinyl-d-phenylglycine ethylester (C16C2) showed the smallest volume of central compartment and smallest volume of distribution at steady state and the second smallest clearance, being the most effective inhibitor in vivo. The IC50 value of ADR or 4-HC for HuCCT1 cells decreased greater by treatment with C16C2 in a dose-dependent manner, paralleling the decrease in GSTP1-1 activity, than that of ADR or 4-HC alone. The antitumor activity of ADR or cyclophosphamide was clearly enhanced by combination therapy with C16C2 in a xenograft model. In conclusion, our results demonstrated that GSTP1-1 is a resistance factor for anticancer drugs in cholangiocarcinoma and that C16C2, a GSTP1-1-specific inhibitor, is a potent agent against the resistance.

Antisense oligodeoxynucleotides directed against aspartyl (asparaginyl) beta-hydroxylase suppress migration of cholangiocarcinoma cells

BACKGROUND

Aspartyl (asparaginyl) beta-hydroxylase (AAH) is an alpha-ketoglutarate-dependent dioxygenase that hydroxylates aspartate and asparagine residues in EGF-like domains of proteins. The consensus sequence for AAH beta-hydroxylation occurs in signaling molecules such as Notch and Notch homologs, which have roles in cell migration.

AIM

This study evaluated the potential role of AAH in cell migration using cholangiocarcinoma cell lines as models due to their tendency to widely infiltrate the liver.

METHODS

Five human cholangiocarcinoma cell lines established from human tumors were examined for AAH expression and motility. The effect of antisense oligodeoxynucleotide inhibition of AAH on cholangiocarcinoma cell migration was investigated.

RESULTS

Western blot analysis detected the approximately 86 kDa AAH protein in all five cholangiocarcinoma cell lines, and higher levels of AAH in cell lines derived from moderately or poorly differentiated compared with well-differentiated tumors. Immunocytochemical staining and fluorescence activated cell sorting analysis revealed both surface and intracellular AAH immunoreactivity. Using the phagokinetic non-directional migration assay and a novel ATPLite luminescence-based directional migration assay, we correlated AAH expression with motility. Correspondingly, antisense and not sense or mutated antisense AAH oligodeoxynucleotides significantly inhibited AAH expression and motility in cholangiocarcinoma cells.

CONCLUSIONS

AAH over-expression may contribute to the infiltrative growth pattern of cholangiocarcinoma cells by promoting motility.

Helicobacter pylori and the risk of benign and malignant biliary tract disease

BACKGROUND

The etiology of tumors arising in the biliary tract remains unclear. Several previous studies have detected Helicobacter pylori organisms in bile from patients with gallstones or cholecystitis. The objective of this study was to determine whether there is an association between H. pylori in bile and biliary tract carcinoma.

METHODS

The authors used polymerase chain reaction (PCR) assays to detect the presence of H. pylori in the stomach and bile from 89 patients: Sixty-three disease free patients had biliary calculi, 15 patients had carcinoma of the biliary tract, and 11 patients had neither gallstones nor carcinoma. Bile was considered to contain H. pylori only if the results of PCR determinations were positive in two or more samples assayed independently in two separate laboratories.

RESULTS

There was a strong association between the presence of H. pylori in the stomach and in the bile (P < or = 0.01). Biliary H. pylori was associated with age but not with gender, and it was associated strongly with the clinical diagnosis. Patients with gallstones were 3.5 times as likely to have H. pylori in the bile compared with patients in a control group (95% confidence interval [95%CI], 0.8-15.8; P = 0.100), and H. pylori was 9.9 times more frequent in patients with biliary tract carcinoma compared with patients in the control group (95%CI, 1.4-70.5; P = 0.022).

CONCLUSIONS

There is a strong association between biliary tract carcinoma and H. pylori in bile. If these results are confirmed by prospective studies, H. pylori may be responsible for a significant proportion of malignant biliary tract disease.

Cellular and molecular biology of biliary tract cancers

Cancer of the biliary tract has been associated with point mutations of K-ras and beta-catenin proto-oncogenes; alterations of p53, p16, APC, and DPC4 tumor suppressor genes by a combination of chromosomal deletion, mutation, or methylation; and infrequently microsatellite instability. The frequencies of these alterations vary by location and race of the patient, tumor subsite, histology, and associated disease. Advances in the understanding of the genetics of this disease will help in diagnosing biliary tract cancer, screening at-risk patients, and developing therapies.

Cholangiocarcinoma: recent progress. Part 2: molecular pathology and treatment

Part 2 of this review discusses DNA damage in biliary epithelial cells in the development of cholangiocarcinoma, alterations in cell kinetics of biliary epithelial cells, biliary epithelial mitoinhibition, and apoptosis that includes the role of Bcl-2, transforming growth factor-beta, telomerase activities and deregulation of Ras and p53, cancer-associated antigens in cholangiocarcinoma, precancerous lesions, stroma formation and angiogenesis, cancer invasion, cell-cell and cell-matrix interactions, and the mechanism of evasion from immune surveillance. These discussions are followed briefly by treatments such as photodynamic therapy, and surgical approaches comparing resection and liver transplantation.

Expression of G1-S modulators (p53, p16, p27, cyclin D1, Rb) and Smad4/Dpc4 in intrahepatic cholangiocarcinoma

Aberrations of G1-S cell cycle arrest and TGF-beta/Smad pathway are critical events in human carcinogenesis. We studied alterations of both pathways by immunohistochemical staining for p53, p16, p27, cyclin D1, Rb and Smad4/Dpc4 in 42 intrahepatic cholangiocarcinomas (ICCs). Abnormal nuclear overexpression of p53 and cyclin D1 was noted in 15 (35.7%) and 26 (61.9%) cases, respectively. Total loss of p16, p27, Rb and Smad4 was detected in 15 (35.7%), 13 (31.0%), 5 (11.9%) and 19 (45.2%) cases, respectively. Forty cases (95.2%) showed aberrations of at least one of the pathways, of which 21 (50%) revealed abnormality in G1-S pathway only, 17 (40.5%) had abnormalities in both pathways and 2 (4.8%) had an abnormality in TGF-beta/Smad pathway only. Among the examined genes, loss of Smad4 was found to have a positive relationship with the pTNM stage (P < 0.05). The overall stage of the high-altered group (alterations in 2 to 5 of the genes, n = 29) was significantly higher than that of the low-altered group (alteration of one or no gene, n = 13) (P < 0.01). We also examined the expression of above genes in the accompanying biliary dysplasia and found out abnormal expression of p53, cyclin D1 or p16 in 7 out of 13 dysplastic lesions. Our data suggest that abnormal G1-S cell cycle and altered TGF-beta/Smad pathway are major events in cholangiocarcinogenesis. Moreover, there might be a possible cumulative effect of the alterations in the examined genes upon the clinical outcome of patients with resectable ICCs.

Increasing expression of gastrointestinal phenotypes and p53 along with histologic progression of intraductal papillary neoplasia of the liver

Intraductal papillary neoplasia of the liver (IPN-L) was recently proposed as the name for intraductal papillary proliferation of neoplastic biliary epithelium with a fine fibrovascular stalk resembling intraductal papillary mucinous neoplasm of the pancreas. We histochemically and immunohistochemically examined IPN-L alone or associated with hepatolithiasis, with an emphasis on the gastrointestinal metaplasia, nuclear p53 expression, and histologic progression. A total of 66 cases of IPN-L were divided into 4 groups: group 1, IPN-L with low-grade dysplasia (13 cases); group 2, IPN-L with high-grade dysplasia (20 cases); group 3, IPN-L lined with carcinoma in situ and no or microinvasion (19 cases); and group 4, group 3 with distinct invasive carcinoma (14 cases). It is suggested that IPN-L progresses from group 1 to group 4. As controls, 20 cases of nonneoplastic intrahepatic large bile ducts and 17 cases of nonpapillary invasive intrahepatic cholangiocarcinoma (ICC) were used. Biliary epithelial hypersecretion of sialomucin rather than sulfomucin was prevalent in IPN-L, and this was associated with the progression of INP-L. Immunohistochemically, cytokeratin (CK) 20 and MUC2, a gastrointestinal marker, were expressed more frequently in IPN-L than in nonneoplastic bile ducts and nonpapillary ICC (P <0.01), and their incidence were significantly increased in parallel with the progression of IPN-L (P < 0.01). In contrast, expression of CK 7, a biliary marker, was decreased in IPN-L compared with nonpapillary ICC. Nuclear p53 immunostaining was detected in 30% of IPN-L as a whole and increased in tandem with the progression of IPN-L (P < 0.01). It is suggested that IPN-L forms a spectrum of biliary epithelial neoplasia with frequent gastrointestinal metaplasia, different from the usual nonpapillary ICC, and shows stepwise progression from the perspective of mucin profile, gastrointestinal metaplasia, and p53 nuclear expression.

Cholangiocarcinoma of the Hepatic Hilum (Klatskin Tumor)

Since the description by Klatskin in 1965, the management of patients with adenocarcinoma of the hepatic bile duct bifurcation is viewed as a challenging clinical problem with a relatively poor prognosis. Surgery continues to be the mainstay of therapy. Complete resection of the tumor with negative histologic margins offers the best possibility of long-term survival, and hepatic resection is a critical component of the operative approach. Adjuvant chemoradiotherapy has failed to provide a significant survival benefit. Orthotopic liver transplantation for otherwise unresectable lesions remains controversial, as tumor recurrence has been reported in more than 90% of patients. With the shortage of organs, such patients to be selected carefully for transplanation. For patients who present with widespread disease and those with high operative risks, advances in interventional radiology and endoscopy have facilitated nonsurgical management options. Biliary decompression using expandable metallic stents provides superior patency and decreased frequency of hospitalization when compared with plastic stents. Moreover, patients treated with expandable metal stents have survival rates comparable with those who undergo surgical decompression, with fewer early complications. The benefit of external beam radiotherapy for palliation of proximal cholangiocarcinoma is uncertain. Radiotherapy in conjunction with biliary stenting has a survival benefit over stenting alone, but is not without potential toxicity. It should be considered as an adjunct to biliary decompression in all patients with good performance status, because modern conformal CT-based dosimetry can minimize toxicity to normal adjacent tissue. Photodynamic therapy is emerging as a new palliative treatment modality for patients with unresectable tumors in whom stenting has failed. It offers the advantage of an endoscopic delivery system, and unlike radiotherapy, photodynamic therapy may be delivered repeatedly.

Correlation between expression of MUC1 core protein and outcome after surgery in mass-forming intrahepatic cholangiocarcinoma

BACKGROUND

It has been reported that MUC1 is an important prognostic factor in several cancers. This study investigated the importance of MUC1 as a prognostic factor in mass-forming intrahepatic cholangiocarcinoma (m-ICC).

METHODS

In 50 patients with m-ICC who had undergone hepatectomy, expression of MUC1 was investigated. Expression of MUC1 was examined by immunohistochemical staining with monoclonal antibody HMPV, which recognizes the MUC1 core peptide. The immunohistochemical staining patterns of MUC1 were classified into three types: ductal type (the luminal surface membrane of neoplastic cells was stained), cytoplasmic type (the cytoplasm of neoplastic cells was stained dominantly), and negative type.

RESULTS

Expression of MUC1 was detected immunohistochemically in 38 (76%) of 50 cases of m-ICC (ductal type, 18; cytoplasmic type, 20; and negative type, 12). Seventy-five percent of patients with lymph node metastasis had the cytoplasmic type MUC1 expression. Lymph node dissection was performed in only 20 patients, but significant correlation was demonstrated between MUC1 expression and lymph node metastasis (P = 0.0227). The location of MUC1 expression correlated with surgical outcome in m-ICC. Patients with the cytoplasmic type expression showed significantly lower survival rates. Univariate analysis revealed that MUC1 expression was a statistically significant risk factor affecting outcome in m-ICC (P = 0.0028). Furthermore, expression of MUC1 was found to be a statistically significant independent risk factor in multivariate analysis (P = 0.0063).

CONCLUSIONS

The results suggest that evaluation of MUC1 expression may be very useful in predicting the surgical outcome in m-ICC.

c-erbB-2 and c-Met expression relates to cholangiocarcinogenesis and progression of intrahepatic cholangiocarcinoma

AIMS

The c-erbB-2 and c-Met proto-oncogenes are important for tumour invasiveness and metastasis in many types of malignant tumours. Previous studies have indicated that these proteins are associated with carcinogenesis in intrahepatic cholangiocarcinoma. In this study, we examined c-erbB-2 and c-Met expression by immunohistochemistry in hepatolithiasis, intrahepatic cholangiocarcinoma and metastatic lymph node, in order to clarify whether these proteins play a role in carcinogenesis and tumour metastasis in intrahepatic cholangiocarcinoma.

METHODS AND RESULTS

In hepatolithiasis, the staining for c-erbB-2 was positive in 14 of the 23 (61%) cases, while staining for c-Met was positive in eight of the 23 (35%) cases. In intrahepatic cholangiocarcinoma, staining for c-erbB-2 was positive in 45 of the 81 (55%) cases, while staining for c-Met was positive in 28 (35%) cases. The positivity of c-Met staining in intrahepatic cholangiocarcinoma was significantly higher in the differentiated type of cholangiocarcinoma than in the undifferentiated type. In addition, c-Met-positive staining had an inverted correlation with tumour size, the presence of perineural invasion and the presence of lymph node metastasis. c-Met staining had a significantly higher positivity in cases at an early stage of intrahepatic cholangiocarcinoma. In contrast, the positivity of c-erbB-2 staining in intrahepatic cholangiocarcinoma was significantly higher in cases with lymph node metastasis than in cases without. In metastatic lymph nodes, the staining for c-erbB-2 was positive in 20 of the 25 (80%) cases, while staining for c-Met was positive in six of the 25 (24%) cases. There was no difference in survival between c-erbB-2-positive and negative patients. However, the patients with c-Met-positive tumours had a significantly longer survival than those with c-Met-negative tumours in the medium survival term. The multivariate analysis showed the presence of lymph node metastasis, lymphatic permeation and histological differentiation to be independent prognostic factors.

CONCLUSION

These results indicate that increased c-Met expression participates in cholangiocarcinogenesis and in the early developmental stages of intrahepatic cholangiocarcinoma, while increased c-erbB-2 expression contributes to the development of cholangiocarcinogenesis into an advanced stage associated with tumour metastasis.

Microsatellite instability and alternative genetic pathway in intrahepatic cholangiocarcinoma

BACKGROUND/AIMS

Intrahepatic cholangiocarcinoma (ICC) arises from intrahepatic bile duct epithelium and is the second most prevalent among primary liver cancers. The aim of this study was to clarify the mechanism of cholangiocarcinogenesis.

METHODS

We studied the incidence of microsatellite instability (MSI) involving eight highly polymorphic microsatellite markers and alternations of the K-ras, p53 and mdm-2 genes in human ICC tissues. Overexpression of mdm-2 oncoprotein was also immunohistochemically studied.

RESULTS

Of all 65 cases examined, K-ras gene mutation was found in three cases (4.6%) at codon 12. Analysis of p53 alterations was performed in 28 cases including 22 frozen samples and mutations were found in three cases (10.7%). Overexpression of mdm-2 protein was observed in 25 (41.7%) out of 60 cases analyzed. In 22 frozen samples, seven (31.8%) cases showed mdm-2 amplification and four (18.2%) cases revealed MSI-positive phenotype. Among the cases analyzed, all the tumors with mdm-2 amplification/overexpression harbored the wild-type p53 gene and all the microsatellite instability-positive cases were from mass-forming (MF) + periductal-infiltrating (PI) subtype.

CONCLUSIONS

These results suggest that mdm-2 plays a role, which might be partially through inhibiting p53 activity, in cholangiocarcinogenesis and that M

The role of overexpression and gene amplification of cyclin D1 in intrahepatic cholangiocarcinoma

BACKGROUND/AIMS

Intrahepatic cholangiocarcinoma (ICC) is a primary liver malignant tumor with an extremely poor prognosis, but less attention has been directed to factors related to molecular carcinogenesis, including cell cycle proteins. We examined the expression and gene amplification of cyclin D1, the cell cycle regulating protein. Our objective was to evaluate correlations with clinicopathological factors in ICC.

METHODS

Cyclin D1 overexpression and cellular proliferative activity (Ki-67 labeling index) were investigated immunohistochemically, and 20 cases were further investigated for cyclin D1 gene amplification, using differential PCR. We examined the correlation between the expression and gene amplification of cyclin D1 and clinicopathological factors, including overall survival in patients with ICC.

RESULTS

Immunohistochemical analysis revealed an overexpression of cyclin D1 protein in 28 of 66 subjects with ICCs (42%). The cyclin D1 overexpression was associated with poor histological differentiation (P = 0.04), high cellular proliferative activity (P < 0.01), and a poor prognosis (P = 0.02) by univariate analysis, although it is not an independent prognostic factor by multivariate analysis. Cyclin D1 gene amplification was confirmed in five of the 20 patients. Of those five cases of ICC, all had poor histological differentiation, and four of the five ICCs (80%) showed evidence of cyclin D1 immunoreactivity.

CONCLUSIONS

Overexpression and gene amplification of cyclin D1 are frequent and contribute to dedifferentiation and cellular proliferative activity of ICCs, and overexpression also indicates a poor prognosis for patients with ICC.

Clinicopathological factors predicting outcome after resection of mass-forming intrahepatic cholangiocarcinoma

BACKGROUND

The prognosis for patients with intrahepatic cholangiocarcinoma differs according to macroscopic type. The identification of clinical and pathological features that predict outcome in patients with mass-forming intrahepatic cholangiocarcinoma is required in order to determine optimal surgical strategies for patients with this type of tumour.

METHODS

The details of 35 patients with resected mass-forming intrahepatic cholangiocarcinomas were analysed retrospectively. Univariate analysis of potential prognostic factors was performed.

RESULTS

The cumulative survival rate at 1, 3 and 5 years after operation was 58, 33 and 33 per cent respectively. Patients with stage II tumours had a better outcome than those with advanced stage tumours. By univariate analysis, lymphatic invasion, lymph node metastasis, intrahepatic satellite lesions and microscopic resection margin involvement were found to be highly significant variables and were identified as possible risk factors for a poor outcome after operation.

CONCLUSION

When frozen-section examination of lymph nodes reveals negative nodal metastasis, extensive anatomical hepatic resection is indicated for mass-forming intrahepatic cholangiocarcinomas. Intraoperative frozen-section examination of the resection margin to confirm the absence of cancer cells is recommended.

Genetic alterations and growth pattern in biliary duct carcinomas: loss of heterozygosity at chromosome 5q bears a close relation with polypoid growth

Biliary duct carcinomas (BDCs) are relatively rare and the carcinogenic mechanisms underlying their induction are poorly understood. There are two growth patterns, polypoid and non-polypoid infiltrative type, but little information is available concerning the relation between growth pattern and genetic alterations. A comparative study was therefore conducted to clarify if differences in genetic changes, including loss of heterozygosity (LOH) at 5q, 9p, 17p, and 18q, and K-ras mutations exist between polypoid and non-polypoid infiltrative type BDCs. LOH analysis was performed using microsatellite markers and K-ras point mutations were analysed by dot blot hybridisation. The incidences of changes for polypoid and non-polypoid infiltrative types were 73% and 26% on 5q, 63% and 59% on 9p, 55% and 50% on 17p, and 20% and 18% on 18q, and 25% and 27% for K-ras mutations. Most importantly, we found the frequency of 5qLOH to be significantly higher with polypoid growth than in the non-polypoid infiltrative type (p<0.05), especially in extrahepatic duct carcinomas (p<0.05). The incidences of other genetic alterations (LOH at 9p, 17p, and 18q, and K-ras mutations) showed similar rates with both tumour types. The present data suggest that 5qLOH may have a close relation with polypoid growth in BDCs.

Low frequency of p53 and ras mutations in bile of patients with hepato-biliary disease: a prospective study in more than 100 patients

The diagnosis of biliary disease, namely malignant disorders, is frequently hampered by the inconclusive cytology. We investigated prospectively the frequency of molecular changes in p53 and ras compared with cytology in patients with primary or secondary hepato-biliary disease. We investigated 118 consecutive patients, aged 24-89 with the following clinical diagnoses: choledocho/cholecystolithiasis (28), cholangiocellular carcinoma (21), gall bladder tumor (8), liver metastasis (3), autoimmune disease (8), chronic pancreatitis (16), pancreatic carcinoma (11), papillary disease (4), hepatic cirrhosis (6), cholangitis (2), anomalies (2), and normal (9). Bile was aspirated during routine endoscopic retrograde cholangio pancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC). DNA was prepared freshly from a native aliquot. p53 mutations were detected by polymerase chain reaction (PCR) for exons 5 through 8 followed by TGGE. PCR for ras mutations was performed as RFLP-PCR with sequencing. In four cases, mutations in p53 could be found in exons 6 and 7. Twenty-two samples showed ras mutations; ras mutations were found in choledocholithiasis (4/28), bile duct (5/21), gall bladder (3/8) and pancreatic (1/11) carcinoma, liver metastasis (3/3), ulcerative colitis (2/3), PSC (1/2), and chronic pancreatitis (1/16). Cytology was clearly positive in seven cases, suspicious in three other, inconclusive in six, and negative in the rest. The molecular analysis resulted in a sensitivity of 33% and specificity of 87%, respectively, for the diagnosis of a malignant condition. PCR for p53 and ras mutations may aid the diagnosis of primary and secondary (metastatic) hepatobiliary disease if a malignant condition of the bile ducts and the liver is suspected and cytology is inconclusive or negative. However, the incidence of p53 and ras mutations in bile seems less frequent than in other malignant conditions of the gastrointestinal tract and the pancreas and lower than in tissue, leaving a poor sensitivity and specificity. Nevertheless, the presence of a p53 and/or ras mutation per se supports a clinical suspicion of malignancy, even when the conventional cytology is negative or inconclusive.

Cholangiocarcinoma

Despite overall advances in the ability to diagnose and treat patients with cholangiocarcinoma, the prognosis for patients with this malignancy remains poor. Further improvements in the survival of patients with cholangiocarcinoma will come with the early diagnosis of these lesions. New molecular techniques should improve the ability to screen high-risk patients, such as those with primary sclerosing cholangitis, hepatolithiasis, choledochal cysts, and ulcerative colitis. Improvements in imaging will continue, and spiral CT scanning, duplex ultrasonography, MR imaging and, perhaps, PET scans will improve the ability to stage patients with cholangiocarcinoma noninvasively. Complete surgical resection remains the only curative treatment for malignancies of the biliary tract. Aggressive surgical approaches are likely to continue, and the challenge remains in being able to perform these procedures safely in jaundiced and sometimes septic patients. For patients with unresectable lesions, the optimal form of palliation, whether surgical or nonsurgical, remains to be defined. Finally, multicenter, prospective, randomized trials of chemoradiation need to be performed to delineate an effective adjuvant therapy more precisely, and to improve the overall prognosis of patients with cholangiocarcinoma.

Expression of p53 and PCNA in cholangiocarcinoma and primary sclerosing cholangitis

The aim of this study was to identify the pattern and significance of expression of p53 and PCNA in cholangiocarcinoma and primary sclerosing cholangitis. Histological sections from 18 patients with cholangiocarcinoma (3 of the cases were associated with primary sclerosing cholangitis), 10 patients with primary sclerosing cholangitis without cholangiocarcinoma, and 7 patients with cirrhosis without cholangiocarcinoma or primary sclerosing cholangitis were stained immunohistochemically for p53 and PCNA. Samples from 17 patients with cholangiocarcinoma (94%) stained positively for p53. Among these 17 cases, nontumorous bile duct epithelium was positive in 7 (including 3 cases with primary sclerosing cholangitis and 2 with carcinoma in situ), and were positive proliferating bile ductules in 4 cases. The single p53-negative cholangiocarcinoma did not show p53 positivity in either the bile duct epithelium or the proliferating bile ductules. Bile ductal and ductular cells in all 10 patients with primary sclerosing cholangitis without cholangiocarcinoma and in the 7 controls were not reactive for p53. All 18 samples from patients with cholangiocarcinoma (100%) were positive for PCNA protein. Bile duct epithelium was positive for PCNA in nine cases (90%) of primary sclerosing cholangitis without cholangiocarcinoma and in six (85%) controls. Our study showed a high rate of p53 expression (94%) in cholangiocarcinoma. The adjacent uninvolved bile duct epithelium was also immunoreactive for p53 in 7 of 17 patients (41%). These findings suggest an early p53 mutation in bile ductal cells in cholangiocarcinogenesis. Expression of p53 may potentially be used to identify or screen, by bile duct brushings, cases of primary sclerosing cholangitis suspected of harboring cholangiocarcinoma. Expression of PCNA was a universal feature in cholangiocarcinoma.

Allelic loss in human intrahepatic cholangiocarcinoma: correlation between chromosome 8p22 and tumor progression

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignant primary tumor of the liver in Japan. Despite progress in operative techniques and adjuvant therapy, the prognosis of ICC remains very poor. Therefore, it is important to investigate the mechanism of carcinogenesis and progression of ICC. We screened allelic losses at 6 loci, including that of novel tumor-suppressor gene FEZ1 on chromosome 8p, and at 5 microsatellite loci to define the association with tumor-suppressor genes (HNPCC, APC, RB1, p53, DCC) in tumors from 18 unrelated ICC patients by PCR-loss of heterozygosity (LOH) assay and correlated the alterations with clinicopathological parameters. As a result, 61.1% (11 of 18) of patients showed LOH at 1 of the loci at least, and microsatellite instability was observed in 16.7% (3 of 18). At locus D8S258, relatively frequent LOH was detected (17.6%) compared with other loci on chromosome 8p. Among the other 5 chromosomal arms tested, the highest frequency of LOH (23.5%) was observed at D17S153. Fifty percent of cases with the mass-forming + periductal infiltrating type were frequently detected by LOH at D8S258 compared to cases of the mass-forming or intraductal growth type. In conclusion, we show that 1 putative tumor-suppressor gene on 8p22 may relate to progression of ICC and suggest that the p53 tumor-suppressor gene may be associated with carcinogenesis of ICC.

Genes and viruses in hepatobiliary neoplasia

Hepatobiliary neoplasms comprise a significant portion of the worldwide cancer burden. Advances in basic science research have led to rapid progress in our understanding of the molecular events responsible for these dreaded diseases. The genetic changes associated with hepatocellular carcinoma (HCC) have received the most attention. Aflatoxin B1 exposure leads to mutations in the p53 tumor suppressor gene, most commonly a transversion in codon 249 that leads to a substitution of serine for arginine in the p53 protein. Numerous other tumor suppressor genes, oncogenes, and tumor gene pathways are altered in HCC. Hepatitis B virus (HBV) infection is strongly associated with HCC. HBV may cause HCC either directly via the HBV X protein, or indirectly by causing liver inflammation and cirrhosis. Hepatitis C virus (HCV) infection is also associated with HCC. Recent evidence suggests that the HCV core protein may play a role in hepatocarcinogenesis. Several inherited metabolic diseases are associated with HCC. It is likely that these diseases cause HCC indirectly by causing cirrhosis. The molecular pathogenesis of cholangiocarcinoma and gallbladder cancer has not been well defined. However, multiple tumor suppressor genes and oncogenes, including p53 and K-ras, are altered in these tumors. Further molecular characterization of hepatobiliary tumors may lead to earlier diagnosis, better staging, improved treatment planning, and the development of more effective therapies.

Allelotype analysis of intrahepatic cholangiocarcinoma

To identify the chromosomal loci of allelic loss in intrahepatic cholangiocarcinoma (ICC), we performed an allelotype study of 36 ICCs using 55 genome-wide microsatellite markers. Loss of heterozygosity was found most frequently on 8p (65.6%), 17p (64.7%), and 9p (64.5%), followed by 18q (54.2%), 1p (48.5%), 3p (44.8%), 9q (42.1%), 14q (41.7%), 6q (41.7%), and 1q (40.6%). The fractional allelic loss (FAL) values ranged from 0 to 0.731 (mean, 0.322). Analysis of the relationship between FAL values and clinicopathologic parameters disclosed significantly higher FAL values in moderately to poorly differentiated ICCs than in well-differentiated ones (P < .05). In summary, this study defined for the first time the overall number of chromosomes having allelic loss and the chromosomal arms and/or regions potentially involved in the development of ICC.

Cholangiocarcinoma in primary sclerosing cholangitis: K-ras mutations and Tp53 dysfunction are implicated in the neoplastic development

BACKGROUND/AIM

Cholangiocarcinoma is a feared complication of primary sclerosing cholangitis (PSC). Neoplastic bile duct strictures may be difficult to differentiate cholangiographically from the non-neoplastic bile duct irregularities characteristic of this disorder, and the diagnosis of cholangiocarcinoma may be difficult to establish with certainty, even in tissue samples. Thus, new methods which can improve the diagnostic accuracy of cholangiocarcinoma in PSC are needed.

METHODS

We investigated the occurrence of K-ras codon 12 and 13 mutations, p53 protein accumulation, and Ki-67 expression in tumor tissue from PSC patients (n=33) who had developed cholangiocarcinoma, using bile duct specimens exised at liver transplantation of PSC patients without cholangiocarcinoma (n=15) as controls

RESULTS

K-ras mutations were present in 11 (33%) of the cholangiocarcinoma samples and significantly more frequent in females. Nine tumors carried a codon 12 mutation, and 2 had a codon 13 mutation. The most frequent substitutions in codon 12 were GGT-->GAT (n=5) and GGT-->TGT (n=3). None of the control bile ducts had K-ras mutations. p53 protein was accumulated in 10 (31%) of the tumors, as opposed to negative findings in all the control samples. Sixteen (48%) tumors revealed either K-ras mutation or p53 accumulation. Ki-67 positivity was significantly higher in cholangiocarcinomas than in the non-neoplastic bile ducts (median 29% vs 12%, respectively; p=0.011).

CONCLUSION

We conclude that K-ras mutations and p53 dysfunction are implicated in tumorigenesis of cholangiocarcinomas arising in PSC patients and that these abnormalities together with increased Ki-67 index may indicate neoplastic progression of bile ducts in these patients.

TP53 mutations and mdm2 protein overexpression in cholangiocarcinomas

Tumor suppressor protein p53 is a positive regulator of MDM2 gene expression and the mdm2 protein can bind to p53, preventing the transactivation of p53 responsive genes, thus mimicking TP53 mutation. The authors looked for alterations that could affect, directly and indirectly, p53 function in 13 patients with extrahepatic cholangiocarcinoma. Molecular analysis by single strand conformation polymorphism and DNA sequencing revealed that TP53 gene mutations occurred in only 2 of 13 cholangiocarcinomas. High levels of mdm2 protein were found, by immunohistochemical staining, in 61% of the cholangiocarcinomas and in almost all specimens (70%) displaying stabilized p53 protein in the absence and in the presence of TP53 mutations. The finding of co-overexpressed mdm2 and p53 proteins in cholangiocarcinomas indicates that they can upregulate the expression of mdm2 protein to a level sufficient for binding and accumulating p53 in a presumably inactive complexed form. The presence of TP53 mutations or upregulation of MDM2 gene expression in 9 of the 13 cholangiocarcinomas strongly supports that the impairment of the p53 pathway is an important and specific step in cholangiocarcinoma pathogenesis. At variance with other authors, no alteration of p16ink4/CDKN2 gene was observed in all 13 cholangiocarcinomas.

Protein expression and genetic alterations of p53 and ras in intrahepatic cholangiocarcinoma

AIMS

The significance of molecular and genetic alterations of p53 and ras in the development and progression as well as the histological differentiation of intrahepatic cholangiocarcinoma (ICC) was evaluated.

METHODS AND RESULTS

We examined immunohistochemically ras p21 protein and p53-related products (p53 protein, WAF-1 and mdm-2) in 43 cases of ICC. In addition, point mutations of ras and p53 were examined genetically in selected ICC cases by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequence analysis. Point mutation of K-ras gene codon 12 was detected in three of 14 cases and one of 15 cases by PCR-RFLP and direct sequence analysis, respectively. Immunoreactivity of ras p21 protein was not detected. Point mutation of p53 was detected in three of 15 cases. p53 protein was immunohistochemically detectable in 33 of 43 cases. Immunoreactivity of p53 was more frequent in well-differentiated and less frequent in poorly differentiated cases. Immunoreactivity of WAF-1 and mdm-2 was seen in 16 and eight of 43 cases, respectively. Both proteins were frequently detected in the cases positive for p53 protein.

CONCLUSION

These results suggest that dysregulation of ras is involved in at least 20% of ICC and expression of p53 protein is more significantly involved in ICC, particularly in the well and moderately differentiated cases. While some cases of p53 expression may be explainable by point mutation of p53, there may be some epigenetic phenomena that stabilize p53 protein in ICC. That is, wild type p53 may be stabilized and then detectable by forming complexes with other molecules of p53 downstream effector genes, such as WAF-1 and mdm-2.

Expression of p73, a novel protein related to the p53 tumour suppressor p53, and apoptosis in cholangiocellular carcinoma of the liver

p73, the first homologue of the tumour suppressor protein p53, was recently discovered on chromosome 1p36 and has been shown to induce apoptosis in a p53-like manner. The present study was performed with the aim of investigating the expression of p53, its new homologue p73 and the occurrence of apoptosis in cholangiocellular carcinoma. Protein levels of p73 were examined in 41 patients with curatively (R0-) resected cholangiocellular carcinomas with an antiserum, raised against a peptide in the N-terminal domain of p73. The incidence of mutations in the p53 gene was analysed by direct sequencing and also immunohistochemically. Apoptotic cell death was assessed using in-situ end-labelling (ISEL) technique in combination with morphological criteria. The results obtained were correlated with patient survival. Immunostaining of p73 protein was detected in 17/41 carcinomas examined (41%). The immunoreactivity was confined to the cell nucleus. In 15/41 patients (37%), mutations of the p53 gene were observed. Eleven out of these 15 patients stained also positive for p73. In contrast, out of 26 patients without any detectable p53 mutation, only six exhibited p73 immunostaining. We failed to observe a correlation between p73 expression or p53 and apoptosis within a given tumour. Survival analysis including the parameters stage and grade of disease, p73 and p53, and also apoptosis, showed that tumour stage and grade as well as p53 and p73 were significantly related to prognosis. In Cox regression survival analysis, however, only extent of primary tumour and lymph node status had an independent prognostic impact. Our results with a high prevalence of p73 within tumours harbouring mutated p53 gene suggest that p73 could compensate for p53 function. We failed to establish p73 or p53 as independent prognostic factors in cholangiocellular carcinoma of the liver.

p53 but not bcl-2 is expressed by most cholangiocarcinomas: a study of 28 cases

AIMS

To examine the frequency and pattern of expression of p53 and bcl-2 in archival material from patients with cholangiocarcinomas and to evaluate their respective roles in its pathogenesis, diagnosis and prognosis.

METHODS AND RESULTS

Twenty-eight surgical cases of cholangiocarcinomas diagnosed at St James's University Hospital and 16 control cases were immunostained with monoclonal antibodies to p53 and bcl-2 using streptavidin-biotin complex method. Pressure cooker was used for antigen retrieval. Of the cholangiocarcinomas, 85.7% (24/28) overexpressed p53. The intensity of staining in these cases varied from 1+ in 2, 2+ in 10 and 3+ in 12 cases. None of the 28 tumours expressed bcl-2. The well differentiated nature of the tumour made assessment of dysplasia difficult, however, where present it did not express p53 or bcl-2. The bile duct epithelium adjacent to the tumour and in the control cases did not show any significant nuclear staining for either antigen.

CONCLUSIONS

Overexpression of p53 appears to play an important role as a late event in the pathogenesis of cholangiocarcinomas, while we found no evidence of bcl-2 overexpression. The expression of p53 in 86% of the invasive tumours, as compared to its lack in the adjacent normal bile duct epithelium, makes it potentially useful in the diagnostic histopathology of these cases.

Increased telomerase activity in intrahepatic cholangiocellular carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters

Telomerase activities in intrahepatic cholangiocarcinomas induced by N-nitrosobis(2-oxopropyl)amine (BOP) in female hamsters were determined using a telomeric repeat amplification protocol (TRAP) assay followed by densitometric quantification. Each determination was repeated to confirm the results and telomerase activity was also detected by gel electrophoresis. An increase was evident in all of 10 cholangiocarcinomas examined, with levels ranging from 2.48 to 4.40 times the normal liver value by densitometric quantification. This finding of a consistent increase suggests that telomerase activation is involved in the development of intrahepatic cholangiocarcinomas and immortalization of cancer cells.

Relative contribution of Ki-ras gene analysis and brush cytology during ERCP for the diagnosis of biliary and pancreatic diseases

BACKGROUND

Ki-ras mutation analysis from material collected during ERCP has been claimed to improve the diagnosis of pancreatic and bile duct carcinomas as compared with conventional cytology. Our aim was to study the relative contribution of both Ki-ras analysis and brush cytology in patients with a significant stricture at ERCP.

METHODS

Brushings were collected in duplicate for both analyses in 142 patients in whom a definitive diagnosis was obtained by histology or a minimal follow-up of 6 months.

RESULTS

For pancreatic strictures, sensitivity, specificity, and accuracy of Ki-ras analysis vs. cytology in detecting malignancy were 81% vs. 66%, 72% vs. 100%, and 70% vs. 74%, respectively. For biliary strictures, they were 25% vs. 42%, 100% vs. 100%, and 35% vs. 43%, respectively. The combination of the two methods only marginally increased their sensitivity and accuracy in both types of strictures.

CONCLUSION

Ki-ras analysis is a sensitive method for diagnosing pancreatic but not biliary carcinoma. However, its specificity is lowered by a high frequency of Ki-ras mutations in patients with chronic pancreatitis (25%) who did not manifest cancer development within a 6-month follow-up period. In pancreatic duct strictures, brush cytology appears to be more specific in detecting malignancy; specificity for Ki-ras and cytology are equivalent for the diagnosis of malignant bile duct strictures. Therefore, making a clinical decision on the sole basis of Ki-ras analysis is probably not justified in the majority of the cases.

Incidence, etiologic aspects and clinicopathologic features in intrahepatic cholangiocellular carcinoma--a study of 51 cases from a low-endemicity area

A total of 51 cases (19 males and 32 females) of intrahepatic cholangiocellular carcinoma (CCC) from a low-endemicity area of primary liver cancer was analyzed during the periods from 1958 to 1979 and from 1984 to 1991. The mean annual age-adjusted incidence rate was 0.44 for males and 0.56 for females per 100,000 inhabitants. CCC was diagnosed before death in only 31%. There was a female predominance in patients over 70 years of age (p < 0.05). At presentation, malaise (85%), weight loss (73%) abdominal pain (50%) and hepatomegaly (80%) were common. The median survival time from diagnosis was 2 months. The mean age at the time of death was 72 years (range 41-92). At autopsy, cholelithiasis was found in 61% (81% in patients older than 70 years) and cirrhosis in 30% of patients. Cholelithiasis was more common in CCC (p < 0.01) than in hepatocellular carcinoma cases with the same mean age. Not one case of inflammatory bowel disease was found. The gross appearance of the tumor was predominantly massive (49%) or multinodular (35%). The most common histological features were tubular pattern of growth (82%) and abundant fibrous stroma. Metastases were particularly associated with the lymph nodes (41%), skeleton (26%) and lungs (16%).

Determination of pancreatic ductal carcinoma histogenesis by analysis of mucous quality and K-ras mutation

BACKGROUND

The authors sought to elucidate the histogenesis of pancreatic ductal carcinoma by correlating K-ras mutation with mucus type in normal epithelium, mucous cell hyperplasia (MCH), and carcinoma.

METHODS

Seventy-four solid-type carcinomas (SCs), 23 ductectatic-type carcinomas (DCs), and specimens of 24 normal pancreata were studied. By histochemical staining, normal duct epithelia, areas of MCH, and carcinomas were classified as having sulfo-type or sialo-type mucus. Foci from normal, DC, SC, sulfo-type, or sialo-type specimens were assessed for K-ras mutation at codon 12 by nested polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

Of the SCs, 9 were sulfo-type and 65 were sialo-type; all DC specimens were sialo-type, and all normal epithelia were sulfo-type. All foci of sulfo-type, nonneoplastic epithelia were negative for K-ras mutation. In contrast, 124 of 313 sialo-type MCH foci (40%) had a K-ras mutation. Of 74 SCs, only 3 of 9 sulfo-type tumors (33%) were positive for the mutation. Sixty of 65 sialo-type SCs (92%) had a K-ras mutation, whereas 15 of 23 sialo-type DCs (65%) had a mutation. K-ras mutant carcinomas (including both SCs and DCs) were associated with K-ras mutant MCH in 109 of 198 MCHs (55%), whereas carcinomas without a K-ras mutation had mutations in 6 of 68 MCHs (9%). MCH in normal pancreata revealed K-ras mutations in 9 of 51 foci (18%). In addition, in K-ras mutant carcinomas, frequency of K-ras mutation in MCH increased from 27% (11 of 41 foci) of nonpapillary MCHs to 62% (98 of 157 foci) of papillary MCHs; but in K-ras wild-type carcinoma, the mutation rate in MCH was unchanged from 12% (3 of 26 foci) to 7% (3 of 42 foci) in nonpapillary and papillary foci, respectively.

CONCLUSIONS

These results suggest a strong relationship between the risk of pancreatic carcinoma and the presence of combinations of K-ras gene mutation, papillary growth, and expression of sialomucin in foci of MCH.

Mutations of K-ras but not p53 genes in biliary duct and pancreatic duct carcinomas induced in hamsters by cholecystoduodenostomy with dissection of the common duct followed by N-nitrosobis(2-oxopropyl)amine

An experimental model for the induction of extrahepatic biliary duct carcinomas in hamsters given cholecystoduodenostomy with dissection of the extrahepatic duct at the distal end of the common duct (CDDB) followed by N-nitrosobis(2-oxopropyl)amine (BOP) has been reported [Tajima et al. (1994) Jpn. J. Cancer Res., 85, 780-788]. The CDDB procedure greatly accelerates cell turnover in the biliary epithelium. In the present experiment, mutations of K-ras and p53 genes in the induced lesions were investigated by the reverse transcriptase-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) method followed by direct sequencing. Mutations of K-ras, involving a G to A transition in second position of codon 12 of K-ras exon 1, were detected in six out of eight (75%) extrahepatic bile duct carcinomas and six out of eleven (54.5%) pancreatic duct carcinomas. However, no mutations of p53 were observed in either tumor type. The results indicate an association between anomalous pancreaticobiliary junction and development of biliary carcinomas that may be pertinent to the human situation, and indicate that conditions of the model predispose to mutations occurring in K-ras but not p53.

[Palliative therapy of carcinomas of the biliary system]

CARCINOMA OF THE GALLBLADDER: Only patients suffering from advanced disease have symptoms, that is pain, jaundice, weight loss. Mean 5-year survival rate tends to be lower than 5%. Tumors can be resected with negative margins in 15 to 25% of the patients. Obstructive jaundice can be managed with endoscopic biliary stent in 84% of the patients. After radiotherapy tumor regression is observed in 80% of the patients. Their mean survival time is 10 months.

CHOLANGIOCARCINOMAS

More than 90% of the patients present with jaundice. At the time of presentation, 50% of the patients already have metastases to lymph nodes. Mean total survival time of all patients is 12 months. Surgical resection can successfully be performed in 30 to 40% of the patients suffering from proximal cholangiocarcinomas. Distal unresectable tumors are best palliated with an endoscopically placed stent in 97.5% of the patients. Patients having undergone radiotherapy will have a mean survival time of 9 to 12 months. There is a 12% response rate after chemotherapy with single agents and one of 23% after combined regimens. Intraarterial application of chemotherapy results in 44% response rate.

CONCLUSION

Carcinomas of the biliary tract are often diagnosed at advanced inoperable stages. Patients quality of life can be ameliorated by palliative treatment, i.e. biliary stents, radio-, chemotherapy. Mean survival time does normally not exceed 1 year.

Mutational analysis of the p53 and K-ras genes and allelotype study of the Rb-1 gene for investigating the pathogenesis of combined hapatocellular-cholangiocellular carcinomas

Because combined hepatocellular-cholangiocellular carcinoma is rare and its biological features and pathogenesis have not been well established, we investigated alterations of the p53, K-ras and Rb-1 genes, as well as expression patterns of carcinoembryonic antigen and keratin, in seven combined hepatocellular-cholangiocarcinomas out of 557 hepatocellular carcinomas autopsied at Tokyo University during 30 years. Mutations of the p53 gene were found in two cases, at codon 244 (GGC to TGC) in the cholangiocellular carcinoma component of case 1 (mixed type, showing an intimate intermingling of both elements) and at codon 234 (TAC to AAC) in both components of case 5 (combined type, consisting of contiguous but independent masses of both elements). Mutation of the K-ras gene (codon 12, GGT to GAT) was seen only in the cholangiocellular carcinoma component of clinically apparent double cancer, case 6. Allelic alteration of the Rb-1 gene was observed in two cases, deletion of both alleles in the hepatocellular carcinoma component of case 3 (combined type) and replication error of the same pattern in both components of case 4 (mixed type). Immunohistochemical analysis showed that the hepatocellular carcinoma components of five cases (cases 2, 3, 5, 6, 7) were immunoreactive for keratin, suggesting biliary epithelial transformation. In four of the five cases (cases 3 and 5 combined, case 7 mixed and case 6 double cancer), cholangiocellular carcinoma components were also positive for keratin. These results suggest that both components of combined hepatocellular-cholangiocarcinoma have the same genetic and phenotypic character and might have arisen from the same origin in some cases.

Ki-ras point mutations and proliferation activity in biliary tract carcinomas

The association between Ki-ras mutations and proliferation activity was investigated in a comprehensive series of biliary tract carcinomas (BTCs). We precisely microdissected samples of tissue from paraffin-embedded sections of 77 BTCs including 22 intrahepatic cholangiocarcinomas (ICCs), 36 extrahepatic cholangiocarcinomas (ECCs), and 19 gall bladder carcinomas (GBCs). Ki-ras mutations at exons 1 and 2 were determined by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method and confirmed by direct sequencing. Proliferation activity was immunohistochemically assessed to generate proliferating cell nuclear antigen labelling indices (PCNA LIs). Ki-ras mutations were detected in 10 of 22 ICCs (45%), 24 of 36 ECCs (67%), and in 16 of 19 GBCs (84%). The frequency of Ki-ras mutations in peripheral type ICCs was 33% (4 of 12) and that in the hilar type ICCs was 60% (6 of 10). In ECCs the highest value of 82% (9 of 11) was found for carcinomas located in the lower part of the biliary tree. Mean PCNA LI in mutation-positive BTCs was significantly elevated compared with the mutation-negative value. These results indicate frequent involvement of Ki-ras mutations in BTCs, especially in GBCs and in distal ECCs, and that carcinomas harbouring a mutation feature high cell proliferation activity.