Details of human epidermal growth factor receptor 2 status in 454 cases of biliary tract cancer.

Human epidermal growth factor receptor 2 (HER2)-targeted therapy has improved clinical outcomes in patients with HER2-positive breast and gastric cancers, although ineffective or recurrent cases are present. One reason for this is the heterogeneity of HER2 expression in cancer cells. The aim of this study was to investigate the clinicopathological characteristics and HER2 status of patients with biliary tract cancers (BTCs). We examined HER2 protein expression by immunohistochemistry, HER2 gene amplification by fluorescence in situ hybridization, and both HER2 protein and gene levels simultaneously by gene-protein assay. Samples were collected from 454 patients who underwent surgical resection for BTCs (110 intrahepatic cholangiocarcinomas [ICC], 67 perihilar extrahepatic cholangiocarcinomas [ECC-Bp], 119 distal extrahepatic cholangiocarcinomas [ECC-Bd], 80 gallbladder carcinomas [GBC], and 79 ampullary carcinomas [AVC]). HER2 status was assessed according to the guidelines for HER2 testing in gastroesophageal adenocarcinoma. HER2-positive status was detected in 14.5% of BTCs (3.7% of ICC, 3.0% of ECC-Bp, 18.5% of ECC-Bd, 31.3% of GBC, and 16.4% of AVC). Furthermore, HER2-positivity tended to correlate with low histological grade, tumor histology, and macroscopic features in certain tumors. HER2 heterogeneity was common and highly frequent (83%) in BTC cases. Reduced HER2 protein expression in the deeper invasive areas with simultaneous dedifferentiation was frequently observed in HER2-positive cancer cells. The findings of this study suggest that a large subgroup of HER2-positive BTC cases can be considered for HER2-targeted therapy. Moreover, the HER2 status in BTCs should be determined carefully using a sensitive approach toward larger cancer tissues.

Phase I study of resminostat, an HDAC inhibitor, combined with S-1 in patients with pre-treated biliary tract or pancreatic cancer.

Resminostat is an oral hydroxamate inhibitor of class I, IIb, and IV histone deacetylases. S-1 is widely used to treat biliary tract cancer and pancreatic cancer in Japan. We performed a phase I study of resminostat combined with S-1 as second-line or later therapy in Japanese patients with biliary tract or pancreatic cancer. A total of 27 patients were enrolled. We determined the optimal regimen for resminostat/S-1 therapy in part 1, and investigated its safety and efficacy in part 2. In part 1, 17 patients were enrolled. One DLT (anorexia and stomatitis, respectively) occurred with each of regimens 2 and 3. In part 2, an additional 10 patients received regimen 3, which was selected in part 1. Regimen 3 was resminostat (200 mg/day on Days 1 to 5 and Days 8 to 12: 5 days on/2 days off) plus S-1 (80-120 mg/day according to body surface area on Days 1 to 14) repeated every 21 days. A total of 16 patients (13 with biliary tract cancer and 3 with pancreatic cancer) received regimen 3 and it was well tolerated. The most frequent treatment-related adverse events were thrombocytopenia and anorexia (11 patients each, 69%). The disease control rate was 81.3% (84.6% for biliary tract cancer and 66.7% for pancreatic cancer, respectively). Median progression-free survival was 3.1 months (5.5 and 2.3 months), while median overall survival was 8.8 months (10.2 and 4.7 months). In conclusion, regimen 3 was well tolerated by patients with pre-treated biliary tract or pancreatic cancer.

HER2/HER3 pathway in biliary tract malignancies; systematic review and meta-analysis: a potential therapeutic target?

Human epidermal growth factor receptor 2 (HER2) overexpression and amplification have been reported as predictive markers for HER2-targeted therapy in breast and gastric cancer, whereas human epidermal growth factor receptor 3 (HER3) is emerging as a potential resistance factor. The aim of this study was to perform a systematic review and meta-analysis of the HER2 and HER3 overexpression and amplification in biliary tract cancers (BTCs). An electronic search of MEDLINE, American Society of Clinical Oncology (ASCO), European Society of Medical Oncology Congress (ESMO), and American Association for Cancer Research (AACR) was performed to identify studies reporting HER2 and/or HER3 membrane protein expression by immunohistochemistry (IHC) and/or gene amplification by in situ hybridization (ISH) in BTCs. Studies were classified as "high quality" (HQ) if IHC overexpression was defined as presence of moderate/strong staining or "low quality" (LQ) where "any" expression was considered positive. Of 440 studies screened, 40 met the inclusion criteria. Globally, HER2 expression rate was 26.5 % (95 % CI 18.9-34.1 %). When HQ studies were analyzed (n = 27 studies), extrahepatic BTCs showed a higher HER2 overexpression rate compared to intrahepatic cholangiocarcinoma: 19.9 % (95 % CI 12.8-27.1 %) vs. 4.8 % (95 % CI 0-14.5 %), respectively, p value 0.0049. HER2 amplification rate was higher in patients selected by HER2 overexpression compared to "unselected" patients: 57.6 % (95 % CI 16.2-99 %) vs. 17.9 % (95 % CI 0.1-35.4 %), respectively, p value 0.0072. HER3 overexpression (4/4 HQ studies) and amplification rates were 27.9 % (95 % CI 9.7-46.1 %) and 26.5 % (one study), respectively. Up to 20 % of extrahepatic BTCs appear to be HER2 overexpressed; of these, close to 60 % appear to be HER2 amplified, while HER3 is overexpressed or amplified in about 25 % of patients. Clinical relevance for targeted therapy should be tested in prospective clinical trials.

Changes of activity and isoforms of alkaline sphingomyelinase (nucleotide pyrophosphatase phosphodiesterase 7) in bile from patients undergoing endoscopic retrograde cholangiopancreatography.

BACKGROUND: Alkaline sphingomyelinase (NPP7) is an ecto-enzyme expressed in intestinal mucosa, which hydrolyses sphingomyelin (SM) to ceramide and inactivates platelet activating factor. It is also expressed in human liver and released in the bile. The enzyme may have anti-tumour and anti-inflammatory effects in colon and its levels are decreased in patients with colon cancer and ulcerative colitis. Active NPP7 is translated from a transcript of 1.4 kb, whereas an inactive form from a 1.2 kb mRNA was found in colon and liver cancer cell lines. While the roles of NPP7 in colon cancer have been intensively studied, less is known about the function and implications of NPP7 in the bile. The present study examines the changes of NPP7 in bile of patients with various hepatobiliary diseases. METHODS: Bile samples were obtained at endoscopic retrograde cholangiopancreatography (ERCP) in 59 patients with gallstone, other benign disease, tumour, and primary sclerosing cholangitis (PSC). The NPP7 activity was determined. The appearance of the 1.4 and 1.2 kb products in the bile was examined by Western blot. The results were correlated to the diseases and also plasma bilirubin and alkaline phosphatase. RESULTS: NPP7 activity in the tumour group was significantly lower than in the gallstone group (p < 0.05). The activity in the tumour plus PSC group was also lower than in gallstone plus other benign disease group (p < 0.05). Within the tumour group NPP7 activity was lowest in cholangiocarcinoma patients, being only 19% of that in gallstone patients. Bilirubin correlated inversely to NPP7 and was higher in the tumour than in the gallstone group. Western blot identified both the 1.4 kb and the 1.2 kb products in most bile samples. The density ratio for the 1.4/1.2 kb products correlated to NPP7 activity significantly. Two patients (one PSC and one cholangiocarcinoma) lacking NPP7 activity had only the 1.2 kb form in bile. CONCLUSION: NPP7 activity and the ratio of 1.4/1.2 kb products in bile are significantly decreased in malignancy, particularly in cholangiocarcinoma. The implications of the finding in diagnosis of cholangiocarcinoma and 1.2 kb product in hepatobiliary diseases require further investigation.

Cancer detection by ubiquitin carboxyl-terminal esterase L1 methylation in pancreatobiliary fluids.

AIM: To evaluate the utility of measuring epigenetic alterations in pancreatic and biliary fluids in determining molecular markers for pancreatobiliary cancers. METHODS: DNA was extracted from undiluted pancreatic and biliary fluids. As a surrogate for a genome-wide hypomethylation assay, levels of long interspersed nuclear element-1 (LINE-1) methylation were analyzed using bisulfite pyrosequencing. CpG island hypermethylation of 10 tumor-associated genes, aryl-hydrocarbon receptor repressor, adenomatous polyposis coli, calcium channel, voltage dependent, T type α1G subunit, insulin-like growth factor 2, O-6-methyl-guanine-DNA methyltransferase, neurogenin 1, CDKN2A, runt-related transcription factor 3 (RUNX3), secreted frizzled-related protein 1, and ubiquitin carboxyl-terminal esterase L1 (UCHL1), was analyzed using MethyLight. To examine the role of CpG methylation and histone deacetylation in the silencing of UCHL1, human gallbladder carcinoma cell lines and pancreatic carcinoma cell lines were treated with 2 or 5 µmol/L 5-AZA-dC for 72 h or 100 nmol/L Trichostatin A for 24 h. After the treatment, UCHL1 expression was analyzed by real-time reverse transcription-polymerase chain reaction. RESULTS: Pancreatobiliary cancers exhibited significantly lower LINE-1 methylation levels in pancreatic and biliary fluids than did noncancerous pancreatobiliary disease (58.7% ± 4.3% vs 61.7% ± 2.2%, P = 0.027; 53.8% ± 6.6% vs 57.5% ± 1.7%, P = 0.007); however, LINE-1 hypomethylation was more evident in pancreatic cancer tissues than in pancreatic fluids (45.4% ± 5.5% vs 58.7% ± 4.3%, P < 0.001). CpG island hypermethylation of tumor-associated genes was detected at various frequencies, but it was not correlated with LINE-1 hypomethylation. Hypermethylation of the UCHL1 gene was cancer-specific and most frequently detected in pancreatic (67%) or biliary (70%) fluids from patients with pancreatobiliary cancer. As a single marker, hypermethylation of the UCHL1 gene in pancreatic and biliary fluids was most useful for the detection of pancreatic and pancreatobiliary cancers, respectively (100% specificity). Hypermethylation of the UCHL1 and RUNX3 genes in pancreatic and biliary fluids was the most useful combined marker for pancreatic (87% sensitivity and 100% specificity) and pancreatobiliary (97% sensitivity and 100% specificity) cancers. Treatment with a demethylating agent, 5-AZA-2'-deoxycytidine, restored UCHL1 expression in pancreatobiliary cancer cell lines. CONCLUSION: Our results suggest that hypermethylation of UCHL1 and RUNX3 in pancreatobiliary fluid might be useful for the diagnosis of pancreatobiliary cancers.

Sequence dependence of MEK inhibitor AZD6244 combined with gemcitabine for the treatment of biliary cancer.

PURPOSE: MEK inhibition has clinical activity against biliary cancers and might therefore be successfully combined with gemcitabine, one of the most active chemotherapy agents for these cancers. As gemcitabine is active in S-phase, and the extracellular signal-regulated kinase (ERK) pathway has a major role driving cell-cycle progression, concurrent use of a MEK inhibitor could potentially antagonize the effect of gemcitabine. We therefore tested the sequence dependence of the combination of gemcitabine and the MEK inhibitor AZD6244 using a series of biliary cancer models. EXPERIMENTAL DESIGN: Primary xenografts were established from patients with gallbladder and distal bile duct cancer and grown in severe combined immunodeficient (SCID) mice at the subcutaneous site. Plasma and tumor drug levels and the time course for recovery of ERK signaling and S-phase were measured in tumor-bearing mice treated for 48 hours with AZD6244 and then monitored for 48 hours off treatment. On the basis of these results, two different treatment schedules combining AZD6244 with gemcitabine were tested in four different biliary cancer models. RESULTS: DNA synthesis was suppressed during treatment with AZD6244, and reentry into S-phase was delayed by approximately 48 hours after treatment. Strong schedule dependence was seen in all four biliary cancer models tested, suggesting that combined treatment with AZD6244 plus gemcitabine would be more active in patients with biliary cancer when gemcitabine is given following a 48-hour interruption in AZD6244 dosing, rather than concurrently. CONCLUSIONS: The combination of AZD6244 plus gemcitabine is highly schedule dependent, and predicted to be more effective in the clinic using sequential rather than simultaneous dosing protocols.

CDK10 functions as a tumor suppressor gene and regulates survivability of biliary tract cancer cells.

Cyclin-dependent kinase 10 (CDK10) is a member of the Cdc2 family of kinases, and has been demonstrated to be an important determinant of resistance to endocrine therapy for breast cancer. To investigate the expression and possible function of CDK10 in biliary tract cancer (BTC), we systematically examined CDK10 in tissues and cell lines. We found that expression of CDK10 was downregulated in both biliary tract tumors and cell lines. Remarkably, the expression of CDK10 correlated with clinical characteristics. Overexpression or knockdown of CDK10, respectively, inhibited or promoted cell proliferation, colony formation and migration. This suggests that CDK10 functions as a tumor suppressor gene in BTC. Overexpression of CDK10 caused malignant cells to become sensitive to chemotherapy and other hostile environments, suggesting that CDK10 functions to regulate survivability of BTC cells. We investigated the expression of six genes to resolve the mechanism. c-RAF was negatively regulated by CDK10 in both cells and specimens. Our results indicate that CDK10 plays a crucial role in the growth and survivability of biliary tract cancer, and offers a potential therapeutic target for this fatal disease.

Targeting EGFR/HER2 pathways enhances the antiproliferative effect of gemcitabine in biliary tract and gallbladder carcinomas.

BACKGROUND: Advanced biliary tract carcinomas (BTCs) have poor prognosis and limited therapeutic options. Therefore, it is crucial to combine standard therapies with molecular targeting. In this study EGFR, HER2, and their molecular transducers were analysed in terms of mutations, amplifications and over-expression in a BTC case series. Furthermore, we tested the efficacy of drugs targeting these molecules, as single agents or in combination with gemcitabine, the standard therapeutic agent against BTC. METHODS: Immunohistochemistry, FISH and mutational analysis were performed on 49 BTC samples of intrahepatic (ICCs), extrahepatic (ECCs), and gallbladder (GBCs) origin. The effect on cell proliferation of different EGFR/HER2 pathway inhibitors as single agents or in combination with gemcitabine was investigated on BTC cell lines. Western blot analyses were performed to investigate molecular mechanisms of targeted drugs. RESULTS: EGFR is expressed in 100% of ICCs, 52.6% of ECCs, and in 38.5% of GBCs. P-MAPK and p-Akt are highly expressed in ICCs (>58% of samples), and to a lower extent in ECCs and GBCs (<46%), indicating EGFR pathway activation. HER2 is overexpressed in 10% of GBCs (with genomic amplification), and 26.3% of ECCs (half of which has genomic amplification). EGFR or its signal transducers are mutated in 26.5% of cases: 4 samples bear mutations of PI3K (8.2%), 3 cases (6.1%) in K-RAS, 4 (8.2%) in B-RAF, and 2 cases (4.1%) in PTEN, but no loss of PTEN expression is detected. EGI-1 cell line is highly sensitive to gemcitabine, TFK1 and TGBC1-TKB cell lines are responsive and HuH28 cell line is resistant. In EGI-1 cells, combination with gefitinib further increases the antiproliferative effect of gemcitabine. In TFK1 and TGBC1-TKB cells, the efficacy of gemcitabine is increased with addiction of sorafenib and everolimus. In TGBC1-TKB cells, lapatinib also has a synergic effect with gemcitabine. HuH28 becomes responsive if treated in combination with erlotinib. Moreover, HuH28 cells are sensitive to lapatinib as a single agent. Molecular mechanisms were confirmed by western blot analysis. CONCLUSION: These data demonstrate that EGFR and HER2 pathways are suitable therapeutic targets for BTCs. The combination of gemcitabine with drugs targeting these pathways gives encouraging results and further clinical studies could be warranted.

Ribonucleotide reductase subunit M1 assessed by quantitative double-fluorescence immunohistochemistry predicts the efficacy of gemcitabine in biliary tract carcinoma.

Gemcitabine is a commonly used chemotherapeutic agent for advanced biliary tract carcinoma (BTC), although its efficacy is insufficient. Therefore, it is essential to establish new diagnostic methods, which can predict responders before the treatment. The aim of this study is to identify the most reliable chemoresistance marker to gemcitabine in BTC among the 4 molecules (hENT1, dCK, RRM1 and RRM2) involved in gemcitabine metabolism. The expression of 4 molecules were investigated in 5 BTC cell lines, and correlated with gemcitabine sensitivity. RRM1 protein was also assessed by quantitative double-fluorescence immunohistochemistry (qDFIHC) in 10 patients with unresectable or recurrent BTC who received gemcitabine-based chemotherapy. RRM1 and RRM2 protein strongly correlated with the IC(50) value for gemcitabine in BTC cell lines (R=0.935, 0.771, respectively). In addition, patients with low RRM1 were significantly more sensitive to gemcitabine (p=0.033), and their survival was significantly better than patients with high RRM1 (p=0.001). In conclusion, RRM1 particularly in protein level is a reliable marker for gemcitabine resistance in BTC. Furthermore, qDFIHC is a useful method for the assessment of RRM1 protein, in order to design a tailor-made chemotherapeutic regimen for BTC patients.

Thymidylate synthase and dihydropyrimidine dehydrogenase are upregulated in pancreatic and biliary tract cancers.

PURPOSE: To investigate a rationale of pancreatobiliary cancers, thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) concentrations in cancer tissues were evaluated. PATIENTS AND METHODS: Twenty-nine patients with pancreatic cancer (PC) and 43 with biliary tract cancer (BTC; 27 cases of bile duct cancer, 8 of gallbladder cancer and 8 of cancer of the papillary area) were included. ELISA was used to assess the concentrations of TS and DPD in cancerous and noncancerous tissues. All 82 patients were followed up at least 12 months after surgery. We compared patient survivals between the 2 groups, taking TS and DPD cutoff as median values, high versus low DPD and high versus low TS in the cancerous tissue of PC and BTC patients. RESULTS: As for PC, DPD and TS concentrations were significantly higher in cancerous than in noncancerous tissues (p = 0.016 vs. 0.036). In BTC, TS concentration was higher in cancerous than in noncancerous tissue (p = 0.0001). Patients with low TS and DPD concentrations had a tendency to have a better disease-free survival than those with high TS and DPD concentrations in PC groups; especially, BTC patients' disease-free survival with high TS was significantly longer than that with low TS (p = 0.0083). DISCUSSION: TS and DPD levels had a tendency to be high in PC and BTC cancerous tissues. High TS in the cancerous tissue was associated with better disease-free survival in BTC.

Development of new drug strategies in infrequent digestive tumors: esophageal, biliary tract, and anal cancers.

PURPOSE OF REVIEW: In the last years, interesting advances have been reported in the treatment of infrequent digestive tumors. The increasing development of new targeted therapies in human cancer has also impacted in these rare gastrointestinal malignancies providing a wide range of possibilities in the design of future clinical trials. RECENT FINDINGS: The inhibition of angiogenesis and the blockage of the epidermal growth factor receptor pathway have provided the most interesting activity in recently reported studies for esophageal and biliary tract carcinomas. Additionally, several targeted therapies have been developed to target the main kinase proteins of the most important pathways of these malignancies. The results of the biggest phase III trial in locally advanced anal carcinoma have been recently published. Finally, the inhibition of epidermal growth factor receptor has also showed promising activity in anal carcinomas. SUMMARY: Recent advances in the knowledge of molecular mechanism of carcinogenesis have led to meaningful changes in the management of gastrointestinal cancers. Although the major advances in targeted therapy have been introduced in the treatment of colorectal cancer, new interesting approaches have been reported in less frequent gastrointestinal tumors such as esophageal, biliary tract, and anal canal carcinoma opening a new hope in the treatment of these rare tumors in the molecular targeted therapy era.

Analysis of hTERT mRNA expression in biliary tract and pancreatic cancer.

BACKGROUND/PURPOSE: Telomerase, an enzyme that prevents the loss of telomere regions consisting of TTAGGG repeats, which maintain the stability of cells, is considered to be involved in cell immortality and cancer growth. Recent genetic analysis has shown that the mRNA for the catalytic subunit of human telomerase reverse transcriptase (hTERT) is expressed in many cancer tissues. METHODS: In this study, we measured hTERT mRNA levels in bile samples from patients with pancreatobiliary disease, and we combined the hTERT mRNA analysis with conventional cytology to achieve an accurate preoperative diagnosis. Bile samples were obtained from 19 patients with biliary tract cancer, 6 with gallbladder cancer, 10 with pancreatic cancer, 1 with gastric cancer, and 10 with benign disease. These samples were examined cytologically, and analyzed for hTERT mRNA levels. RESULTS: The Combination of cytological examination and hTERT mRNA analysis achieved a positive rate of 78.9% in diagnosing biliary tract cancer, significantly improving the diagnostic accuracy over that for either method alone (P = 0.01). The diagnostic sensitivity for malignant disease was 66.6%, also significantly improving the diagnostic accuracy compared with either method alone (P = 0.001). CONCLUSIONS: The combination of cytological examination and hTERT mRNA analysis appeared useful for the preoperative diagnosis of malignant biliary tract diseases, but was not superior to diagnostic imaging studies, and therefore remains an adjunct to cytological examination. Further studies should lead to improvements in the combination's diagnostic capabilities.

Multifocal biliary cystadenocarcinoma of the liver: CT and pathologic findings.

Biliary cystadenocarcinoma is a rare tumor that originates from the hepatobiliary epithelium. Although this tumor can affect any portion of the biliary tree, intrahepatic location is more common. It is usually a slow growing tumor and often asymptomatic until it reaches a considerable size. The lesion is most often solitary and large when discovered; multiple lesions or metastases within the liver are very rare. A 63-year-old man was referred to our institute for weight loss, abdominal discomfort, worsening bulky symptoms in the right upper abdominal quadrant, and an increase in serum aminotransferases that had been present for several months. Spiral CT of the abdomen demonstrated two lesions, a larger one and a distant intrahepatic lesion, with a multiloculated cystic aspect, a thin peripheral capsule, multiple solid peripheral portions, and irregular septa enhancing in the portal phase after intravenous administration of iodinated contrast medium. The diagnosis of multifocal cystadenocarcinoma of the liver was confirmed by surgical laparoscopy and biopsy of the lesion. The patient was treated with chemotherapy.

Homozygous deletions of methylthioadenosine phosphorylase in human biliary tract cancers.

The p16(INK4A)/CDKN2A gene on chromosome 9p21 is a site of frequent allelic loss in human cancers, and in a subset of cases, homozygous deletions at this locus encompass the telomeric methylthioadenosine phosphorylase (MTAP) gene. The MTAP gene product is the principal enzyme involved in purine synthesis via the salvage pathway, such that MTAP-negative cancers are solely dependent on de novo purine synthesis mechanisms. Inhibitors of the de novo pathway can then be used to selectively blockade purine synthesis in cancer cells while causing minimal collateral damage to normal cells. In this study, we determine that 10 of 28 (35%) biliary tract cancers show complete lack of Mtap protein expression. In vitro analysis using a selective inhibitor of the de novo purine synthesis pathway, L-alanosine, shows robust growth inhibition in MTAP-negative biliary cancer cell lines CAK-1 and GBD-1 accompanied by striking depletion of intracellular ATP and failure to rescue this depletion via addition of exogenous methylthioadenosine, the principal substrate of the MTAP gene product; in contrast, no significant effects were observed in MTAP-expressing HuCCT1 and SNU308 cell lines. Colony formation studies confirmed that L-alanosine reduced both number and size of CAK-1 colonies in soft agar assays. Knockdown of Mtap protein by RNA interference in L-alanosine-resistant HuCCT1 cells conferred sensitivity to this agent, confirming that intracellular Mtap protein levels determine response to L-alanosine. Inhibitors of de novo purine synthesis can be a potential mechanism-based strategy for treatment of biliary tract cancers, one third of which show complete loss of MTAP function.

Epidermal growth factor receptor dynamics influences response to epidermal growth factor receptor targeted agents.

Analysis of gene expression of cancer cell lines exposed to erlotinib, a small molecule inhibitor of the epidermal growth factor receptor (EGFR), showed a marked increase in EGFR mRNA in resistant cell lines but not in susceptible ones. Because cetuximab induces EGFR down-regulation, we explored the hypothesis that treatment with cetuximab would interfere with erlotinib-induced EGFR up-regulation and result in antitumor effects. Exposure of the resistant biliary tract cancer cell line HuCCT1 but not the susceptible A431 epidermoid cell line to erlotinib induced EGFR mRNA and protein expression. Combined treatment with cetuximab blunted the erlotinib-induced EGFR up-regulation and resulted in inhibition of cell proliferation and apoptosis in the HuCCT1 cells. Blockage of erlotinib-induced EGFR synthesis in HuCCT1 cells by small interfering RNA resulted in identical antitumor effects as cetuximab, providing mechanistic specificity. In mice xenografted with A431, HuCCT1, and the pancreatic cancer cell line Panc430, maximal growth arrest and decrease in Ki67 proliferation index were documented with combined therapy, and EGFR down-regulation was observed in cetuximab-treated tumors. These results may indicate that resistance to EGFR kinase inhibition may be, at least in part, mediated by a highly dynamic feedback loop consisting of up-regulation of the EGFR upon exposure to EGFR kinase inhibitors. Abrogation of this response by small interfering RNA-mediated EGFR mRNA down-regulation and/or by cetuximab-mediated protein clearance induced tumor arrest across several cancer models with different EGFR expression levels, suggesting that resistance and sensitivity are dynamic events where proportional decrease in the target rather than absolute content dictates outcome.

Transmembrane carbonic anhydrase, MN/CA IX, is a potential biomarker for biliary tumours.

BACKGROUND/AIMS: Carbonic anhydrase isoenzyme IX (MN/CA IX) is a transmembrane protein with a suggested function in maintaining the acid-base balance and intercellular communication. Previous studies have demonstrated that MN/CA IX is expressed in the basolateral plasma membrane of normal biliary epithelial cells, but not in hepatocytes. This study was designed to examine the expression of MN/CA IX in hepatobiliary neoplasms and to elucidate its value as a marker for biliary differentiation. METHODS: Fifty-seven hepatobiliary lesions were immunostained for MN/CA IX using biotin-streptavidin complex method. Twenty samples containing normal biliary epithelium and five containing normal liver tissue were used as controls. RESULTS: In the biliary epithelial tumours, immunostaining for MN/CA IX was mainly localized at the basolateral surface of the epithelial cells, like in normal mucosa. All non-invasive dysplastic lesions and 57% of invasive lesions of gall-bladder expressed MN/CA IX. In liver, 78% of cholangiocellular malignant lesions showed a positive reaction for MN/CA IX, whereas only 33% of hepatocellular carcinomas showed a weak immunoreaction. CONCLUSIONS: Our results suggest that abnormal expression of MN/CA IX may be linked to malignant transformation of hepatobiliary cells. In addition, it seems to be a promising marker for biliary differentiation in hepatobiliary neoplasms.

High expression of thymidylate synthase leads to resistance to 5-fluorouracil in biliary tract carcinoma in vitro.

To evaluate the effect of chemotherapy of 5-fluorouracil (5-FU) in human biliary tract carcinoma, we studied 5-FU sensitivity, thymidylate synthase (TS) content, and dihydropyrimidine dehydrogenase (DPD) activity in 4 human biliary tract carcinoma cell lines compared to 12 various digestive carcinoma cell lines of human organs in vitro. 5-FU sensitivity in the cell lines was analyzed by MTT assay. TS content was analyzed by the [6-(3)H]FdUMP binding assay method, and DPD activity was analyzed by thin-layer chromatography (TLC). 5-FU IC(50) values of biliary tract carcinoma cell lines were significantly higher than those of the carcinoma cell lines of the other digestive organs: 97, 45, 119, and 194 times the concentration of the other digestive, pancreas, colon, and gastric carcinoma cell lines, respectively. TS content of biliary tract carcinoma cell lines was also significantly greater than that of the carcinoma cell lines of the other organs. No difference in DPD activity, however, was recognized between the carcinoma cell lines of each organ. TS content in the cell lines significantly correlated with 5-FU sensitivity, but DPD activity did not. Therefore, in the present study, TS expression was concluded to influence the high resistance to 5-FU of biliary tract carcinoma in comparison with the carcinomas of the other digestive organs.

Detection of telomerase reverse transcriptase mRNA in biopsy specimens and bile for diagnosis of biliary tract cancers.

Human telomerase reverse transcriptase (hTERT), which codes for the catalytic subunit of telomerase, is essential for telomerase activity. Recent studies revealed that levels of hTERT mRNA as well as telomerase activity are high in neoplasm. The purpose of this study was to correlate the expression of hTERT mRNA with telomerase activity in biopsy specimens and bile from biliary tract cancers and to evaluate the potential diagnostic value of hTERT mRNA analysis for biliary malignancy. We analyzed hTERT mRNA and telomerase activity in biopsy specimens and exfoliated bile cells from patients with cholangiocarcinoma, gallbladder carcinoma and bile duct stones. hTERT was detected by either nested reverse transcriptase-polymerase chain reaction (PCR) or real-time PCR. Telomerase activity was examined by a fluorescence-based telomeric repeat amplification protocol assay. Six of 10 malignant biopsy specimens had detectable hTERT and 7 of 10 had telomerase activity. All cases with hTERT expression had telomerase activity. In bile, 7 of 10 malignant patients had detectable hTERT and 3 of 10 had telomerase activity. Importantly, there were no false positive results in tissue specimens or bile examined in 6 non-cancerous cases. In conclusion, the detection of hTERT mRNA in biopsy specimens and bile cells, in combination with routine histologic and cytologic examination may improve the diagnosis of biliary tract cancers.

Detection of telomerase activity in exfoliated cancer cells obtained from bile.

Telomerase is detected by the telomeric repeat amplification protocol (TRAP) assay in more than 85% of primary cancers. In the present study, we determined telomerase activity using exfoliated bile cells obtained from biliary tract neoplasia specimens. The aim of this study was to provide additional information regarding minimally invasive approaches to the detection of biliary tract cancer in combination with routine cytologic examination. We analyzed for telomerase activity bile juice from patients with gallbladder carcinoma, cholangiocarcinoma, cholecystitis and cholangitis. Semiquantitative determination of telomerase activity was performed using both a fluorescence-based TRAP assay on cell extracts and at the cellular level by an in situ TRAP assay. The fluorescence-based TRAP assay detected bile telomerase activity in samples from 4 of 10 patients with biliary tract cancer. In contrast, the in situ TRAP assay detected telomerase positive cells in samples from 6 of 10 patients with biliary tract cancer. However, only one of these samples showed class V cytology. A combination of semiquantitative analysis and an in situ TRAP assay to detect telomerase positive cells may improve the diagnosis of biliary tract cancers with the combination of routine cytologic examination.

Alterations in pancreatic, biliary, and breast carcinomas support MKK4 as a genetically targeted tumor suppressor gene.

Mitogen-activated protein kinase (MAPK) kinase 4 (MKK4) is a component of a stress and cytokine-induced signal transduction pathway involving MAPK proteins. The MKK4 protein has been implicated in activation of JNK1 and p38 MAPK on phosphorylation by conserved kinase pathways. A recent report on the deletion and mutation of the MKK4 gene in human pancreatic, lung, breast, testicle, and colorectal cancer cell lines suggests an additional role for MKK4 in tumor suppression. Both the gene function and the infrequency of mutations might be considered atypical for many human tumor suppressor genes, and constitutional DNA was not previously available to determine whether the reported sequence variants had preceded tumor development. Here, we report that homozygous deletions are detected in 2 of 92 pancreatic adenocarcinomas (2%), 1 of 16 biliary adenocarcinomas (6%), and 1 of 22 breast carcinomas (when combined with reported sequence alterations, 3 of 22 or 14%). In addition, in a panel of 45 pancreatic carcinomas prescreened for loss of heterozygosity, one somatic missense mutation of MKK4 is observed and confirmed in the primary tumor (2%). Mapping of the homozygous deletions further indicated MKK4 to lie at the target of deletion. The finding of a somatic missense mutation in the absence of any other nucleotide polymorphisms or silent nucleotide changes continues to favor MKK4 as a mutationally targeted tumor suppressor gene. Coexistent mutations of other tumor suppressor genes in MKK4-deficient tumors suggest that MKK4 may participate in a tumor suppressive signaling pathway distinct from DPC4, p16, p53, and BRCA2.