Ki-ras mutations as a prognostic factor in extrahepatic bile system cancer. PANK-ras I Project Investigators

Current Standards, Multidisciplinary Approaches, and Future Directions in the Management of Extrahepatic Cholangiocarcinoma

OPINION STATEMENT

Biliary tract cancers are molecularly and anatomically diverse cancers which include intrahepatic cholangiocarcinoma, extrahepatic (perihilar and distal) cholangiocarcinoma, and gallbladder cancer. While recognized as distinct entities, the rarer incidence of these cancers combined with diagnostic challenges in classifying anatomic origin has resulted in clinical trials and guideline recommended strategies being generalized patients with all types of biliary tract cancer. In this review, we delve into the unique aspects, subtype-specific clinical trial outcomes, and multidisciplinary management of patients with extrahepatic cholangiocarcinoma. When resectable, definitive surgery followed by adjuvant chemotherapy (sometimes with selective radiation/chemoradiation) is current standard of care. Due to high recurrence rates, there is growing interest in the use of upfront/neoadjuvant therapy to improve surgical outcomes and to downstage patients who may not initially be resectable. Select patients with perihilar cholangiocarcinoma are being successfully treated with novel approaches such as liver transplant. In the advanced disease setting, combination gemcitabine and cisplatin remains the standard base for systemic therapy and was recently improved upon with the addition of immune checkpoint blockade to the chemotherapy doublet in the recently reported TOPAZ-1 and KEYNOTE-966 trials. Second-line all-comer treatments for these patients remain limited in both options and efficacy, so clinical trial participation should be strongly considered. With increased use of molecular testing, detection of actionable mutations and opportunities to receive indicated targeted therapies are on the rise and are the most significant driver of improved survival for patients with advanced stage disease. Though these targeted therapies are currently reserved for the second or later line, future trials are looking at moving these to earlier treatment settings and use in combination with chemotherapy and immunotherapy. In addition to cross-disciplinary management with surgical, medical, and radiation oncology, patient-centered care should also include collaboration with advanced endoscopists, palliative care specialists, and nutritionists to improve global patient outcomes.

Liquid Biopsy from Bile-Circulating Tumor DNA in Patients with Biliary Tract Cancer

Simple Summary

Utilization of cell free DNA for diagnosing and monitoring patients with biliary tract cancers is emerging and promising. The strength of the present study is in its description of a novel approach using bile rather than blood or tissue samples, which is particularly relevant in biliary tract cancers. This paper largely serves as a proof of concept that ctDNA from bile is potentially feasible.

Abstract

Although liquid biopsy of blood is useful for cancer diagnosis and prediction of prognosis, diagnostic and prognostic value of ctDNA in bile fluid for BTCs are not clear yet. To determine whether liquid biopsy for circulating tumor DNA (ctDNA) can replace tissue biopsy when assessing somatic mutations in biliary tract cancers (BTCs). Bile samples were obtained from 42 patients with BTC. Matched formalin-fixed paraffin-embedded (FFPE) samples were obtained from 20 of these patients and matched plasma samples from 16 of them. Droplet digital PCR (ddPCR) was used for detection KRAS somatic mutation. KRAS mutations were identified in the bile ctDNA of 20 of 42 (48%) patients. Patients with mutant KRAS showed significantly worse survival than those with wild-type KRAS (2-year survival rates: 0% vs. 55.5%, respectively; p = 0.018). There was 80.0% mutational concordance between the paired bile ctDNA and FFPE samples, and 42.9% between the plasma and FFPE samples. On transcriptomic sequencing of one set of paired bile and FFPE samples, expression level of KRAS-associated signaling oncogenes in the bile and tissue samples showed a strong positive correlation (r = 0.991, p < 0.001). Liquid biopsy of bile reliably detect mutational variants within the bile ctDNA of BTC patients. These results suggest that bile is an effective biopsy fluid for ctDNA analysis.

Concentrations of trace elements and KRAS mutations in pancreatic ductal adenocarcinoma

Trace elements are a possible risk factor for pancreatic ductal adenocarcinoma (PDAC). However, their role in the occurrence and persistence of KRAS mutations remains unstudied. There appear to be no studies analyzing biomarkers of trace elements and KRAS mutations in any human cancer. We aimed to determine whether patients with KRAS mutated and nonmutated tumors exhibit differences in concentrations of trace elements. Incident cases of PDAC were prospectively identified in five hospitals in Spain. KRAS mutational status was determined through polymerase chain reaction from tumor tissue. Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Concentrations of trace elements were compared in 78 PDAC cases and 416 hospital-based controls (case-control analyses), and between 17 KRAS wild-type tumors and 61 KRAS mutated tumors (case-case analyses). Higher levels of iron, arsenic, and vanadium were associated with a statistically nonsignificant increased risk of a KRAS wild-type PDAC (OR for higher tertile of arsenic = 3.37, 95% CI 0.98-11.57). Lower levels of nickel and manganese were associated with a statistically significant higher risk of a KRAS mutated PDAC (OR for manganese = 0.34, 95% CI 0.14-0.80). Higher levels of selenium appeared protective for both mutated and KRAS wild-type PDAC. Higher levels of cadmium and lead were clear risk factors for both KRAS mutated and wild-type cases. This is the first study analyzing biomarkers of trace elements and KRAS mutations in any human cancer. Concentrations of trace elements differed markedly between PDAC cases with and without mutations in codon 12 of the KRAS oncogene, thus suggesting a role for trace elements in pancreatic and perhaps other cancers with such mutations. Environ. Mol. Mutagen., 60:693-703, 2019. © 2019 Wiley Periodicals, Inc.

Biliary tract cancers: current knowledge, clinical candidates and future challenges

Biliary tract cancers (BTCs) are rare with poor prognosis. Due to the advent of genomic sequencing, new data have emerged regarding the molecular makeup of this disease. To add to the complexity, various subtypes also harbor a varied genetic composition. The commonly mutated genes associated with this cancer are KRAS, EGFR, IDH, FGFR and BAP1. Various clinical studies are looking at targeting these genetic mutations. Another therapeutic area of note is the potential for the use of immunotherapy in patients with BTC. Although BTC may be a result of chronic inflammation, this does not necessarily translate into increased immunogenicity. This literature review discusses the diverse molecular and immune-related pathways in patients with BTC and their potential therapeutic implications.

Mutation analysis and copy number changes of KRAS and BRAF genes in Taiwanese cases of biliary tract cholangiocarcinoma

BACKGROUND/PURPOSE

Cholangiocarcinoma (CC) is a fatal malignancy originating from biliary tracts and constitutes approximately 10-20% of hepatobiliary cancers. CC is characterized by a very poor prognosis. The definite molecular mechanisms leading to oncogenesis remain unclear. This study aimed to perform mutation analysis and copy number changes of KRAS and BRAF genes of CC in Taiwan.

METHODS

A total of 182 cases of biliary tact CC were studied for point mutation and quantitative real-time polymerase chain reaction analysis of KRAS and BRAF genes. The obtained data were analyzed with clinical and histopathological variables and survival.

RESULTS

KRAS point mutations were detected in intrahepatic CC (7.6%), common bile duct cancer (13.3%), and gallbladder carcinoma (3.3%). BRAF gene amplifications were demonstrated in intrahepatic CC (4.3%), common bile duct cancer (3.3%), and gallbladder cancer (5%). No association was observed between mutation patterns and histopathological features. The analyses of risk factors for overall survival in patients with CC revealed no significant association in age, tumor site, genetic mutation, or amplifications. The tumor stage was the significant prognostic factor.

CONCLUSION

Unlike other studies from American, European, or Japanese groups which showed certain levels of gene mutations in CC, our data revealed a rather low frequency of KRAS mutations and BRAF gene amplifications in CC in Taiwan. Tumor TNM stage was the only significant prognostic parameter in this analysis. It is crucial to gain more information of carcinogenesis, molecular mechanisms and therapeutic strategy in biliary tract cholangiocarcinoma.

Biliary cancer: Utility of next-generation sequencing for clinical management

BACKGROUND

Biliary tract cancers (BTCs) typically present at an advanced stage, and systemic chemotherapy is often of limited benefit.

METHODS

Hybrid capture-based comprehensive genomic profiling (CGP) was performed for 412 intrahepatic cholangiocarcinomas (IHCCAs), 57 extrahepatic cholangiocarcinomas (EHCCAs), and 85 gallbladder carcinomas (GBCAs). The mutational profile was correlated with the clinical outcome of standard and experimental therapies for 321 patients. Clinical variables, detected mutations, and administered therapies were correlated with overall survival (OS) in a Cox regression model.

RESULTS

The most frequent genetic aberrations (GAs) observed were tumor protein 53 (TP53; 27%), cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B; 27%), KRAS (22%), AT-rich interactive domain-containing protein 1A (ARID1A; 18%), and isocitrate dehydrogenase 1 (IDH1; 16%) in IHCCA; KRAS (42%), TP53 (40%), CDKN2A/B (17%), and SMAD4 (21%) in EHCCA; and TP53 (59%), CDKN2A/B (19%), ARID1A (13%), and ERBB2 (16%) in GBCA. Fibroblast growth factor receptor (FGFR; 11%) and IDH mutations (20%) were mostly limited to IHCCA but appeared to be mutually exclusive. In the IHCCA group, TP53 and KRAS mutations were associated significantly with poor OS, whereas FGFR2 mutations were associated with improved OS (P = .001), a younger age at onset, and female sex. IDH1/2 mutations were not prognostic. In a multivariate model, the effects of TP53 and FGFR GAs remained significant (P < .05). Patients with FGFR GAs had superior OS with FGFR-targeted therapy versus standard regimens (P = .006). Targeted therapy in IHCCA was associated with a numerical OS improvement (P = .07).

CONCLUSIONS

This is the largest clinically annotated data set of BTC cases with CGP and indicates the potential of CGP for improving outcomes. CGP should be strongly considered in the management of BTC patients. Cancer 2016;122:3838-3847. © 2016 American Cancer Society.

Gemcitabine and oxaliplatin with or without cetuximab in advanced biliary-tract cancer (BINGO): a randomised, open-label, non-comparative phase 2 trial

BACKGROUND

Gemcitabine plus a platinum-based agent (eg, cisplatin or oxaliplatin) is the standard of care for advanced biliary cancers. We investigated the addition of cetuximab to chemotherapy in patients with advanced biliary cancers.

METHODS

In this non-comparative, open-label, randomised phase 2 trial, we recruited patients with locally advanced (non-resectable) or metastatic cholangiocarcinoma, gallbladder carcinoma, or ampullary carcinoma and a WHO performance status of 0 or 1 from 18 hospitals across France and Germany. Eligible patients were randomly assigned (1:1) centrally with a minimisation procedure to first-line treatment with gemcitabine (1000 mg/m(2)) and oxaliplatin (100 mg/m(2)) with or without cetuximab (500 mg/m(2)), repeated every 2 weeks until disease progression or unacceptable toxicity. Randomisation was stratified by centre, primary site of disease, disease stage, and previous treatment with curative intent or adjuvant therapy. Investigators who assessed treatment response were not masked to group assignment. The primary endpoint was the proportion of patients who were progression-free at 4 months, analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00552149.

FINDINGS

Between Oct 10, 2007, and Dec 18, 2009, 76 patients were assigned to chemotherapy plus cetuximab and 74 to chemotherapy alone. 48 (63%; 95% CI 52-74) patients assigned to chemotherapy plus cetuximab and 40 (54%; 43-65) assigned to chemotherapy alone were progression-free at 4 months. Median progression-free survival was 6·1 months (95% CI 5·1-7·6) in the chemotherapy plus cetuximab group and 5·5 months (3·7-6·6) in the chemotherapy alone group. Median overall survival was 11·0 months (9·1-13·7) in the chemotherapy plus cetuximab group and 12·4 months (8·6-16·0) in the chemotherapy alone group. The most common grade 3-4 adverse events were peripheral neuropathy (in 18 [24%] of 76 patients who received chemotherapy plus cetuximab vs ten [15%] of 68 who received chemotherapy alone), neutropenia (17 [22%] vs 11 [16%]), and increased aminotransferase concentrations (17 [22%] vs ten [15%]). 70 serious adverse events were reported in 39 (51%) of 76 patients who received chemotherapy plus cetuximab (34 events in 19 [25%] patients were treatment-related), whereas 41 serious adverse events were reported in 25 (35%) of 71 patients who received chemotherapy alone (20 events in 12 [17%] patients were treatment-related). One patient died of atypical pneumonia related to treatment in the chemotherapy alone group.

INTERPRETATION

The addition of cetuximab to gemcitabine and oxaliplatin did not seem to enhance the activity of chemotherapy in patients with advanced biliary cancer, although it was well tolerated. Gemcitabine and platinum-based combination should remain the standard treatment option.

FUNDING

Institut National du Cancer, Merck Serono.

Targeted therapy for biliary tract cancers

Biliary tract cancers (BTCs) are a heterogeneous group of malignancies, with a historically poor prognosis as a whole. Until recently, the development of effective therapeutics was hampered by the relatively low incidence, heterogeneity in patients and tumors, and correspondingly poor clinical trial enrollments. With the publication of the landmark phase III ABC-02 trial demonstrating the superiority of gemcitabine and cisplatin combination chemotherapy, the landscape changed for the development of new agents. Despite this progress, there are currently no approved targeted agents for BTC. This review will focus on recent developments in targeted therapeutics, directed against several key signaling pathways in BTC, including epidermal growth factor receptor, angiogenesis, and the mitogen-activated protein kinase pathway. Data from recent phase I and II trials will be discussed, along with a preview of upcoming trials involving targeted therapies.

Characterization of a novel KRAS mutation identified in Noonan syndrome

Noonan syndrome (NS) is the most common non-chromosomal syndrome seen in children and is characterized by short stature, dysmorphic facial features, chest deformity, a wide range of congenital heart defects and developmental delay of variable degree. Mutations in the Ras/mitogen-activated protein kinase (MAPK) signaling pathways cause about 70% of NS cases with a KRAS mutation present in about 2%. In a cohort of 65 clinically confirmed NS patients of Japanese origin, we screened for mutations in the RAS genes by direct sequencing. We found a novel mutation in KRAS with an amino acid substitution of asparagine to serine at codon 116 (N116S). We analyzed the biological activity of this mutant by ectopic expression of wild-type or mutant KRAS. NS-associated KRAS mutation resulted in Erk activation and active Ras-GTP levels, and exhibited mild cell proliferation. In addition, kras-targeted morpholino knocked-down zebrafish embryos caused heart and craniofacial malformations, while the expression of mutated kras resulted in maldevelopment of the heart. Our findings implicate that N116S change in KRAS is a hyperactive mutation which is a causative agent of NS through maldevelopment of the heart.

Meta-analysis of alcohol consumption and risk of extrahepatic bile system cancer

AIM

  Alcohol consumption increases the risk of liver cancer. However, there is still controversy regarding alcohol consumption and the risk of extrahepatic bile system cancer (EBSC). We performed a meta-analysis to provide an overview of the relevant studies and gain more robust estimates of the relationship between alcohol consumption and risk of EBSC.

METHODS

  Relevant studies published between January 1966 and October 2010 were identified by searching Medline, Embase and the Cochrane Library. Studies were selected using a priori defined criteria. The strength of the relationship between alcohol consumption and risk of EBSC was assessed by adjusted odds ratio (OR).

RESULTS

  A total of 113 767 participants from 10 studies (nine case-control studies and one cohort study) were identified in this meta-analysis. The studies provided adjusted overall OR estimates for drinkers versus non-/low drinkers, leading to a pooled adjusted OR of 0.82 (95% confidence interval [CI] = 0.72-0.94, P for heterogeneity = 0.194, I(2)  = 27.2%). The overall adjusted OR of hospital-based studies and population-based studies were 0.80 (95% CI = 0.65-0.99, P = 0.260) and 0.79 (95% CI = 0.64-0.98, P = 0.119), respectively. For the heavy drinkers, the adjusted OR significance increased to 1.58 (95% CI = 0.97-2.57, P for heterogeneity = 0.055, I(2)  = 65.4%), but it had no statistical significance.

CONCLUSION

  There is evidence that moderate alcohol consumption lowers the risk of EBSC compared with non-/low alcohol consumption, but not heavy alcohol consumption. Further multicenter and better controlled studies are required to confirm these findings.

Cetuximab, gemcitabine, and oxaliplatin in patients with unresectable advanced or metastatic biliary tract cancer: a phase 2 study

BACKGROUND

Patients with biliary tract cancer have a poor prognosis, and, until recently, no standard palliative chemotherapy has been defined. We aimed to investigate the efficacy and safety of cetuximab in combination with gemcitabine and oxaliplatin (GEMOX) for first-line treatment of biliary tract cancer.

METHODS

From Oct 1, 2006, to July 26, 2008, patients with unresectable locally advanced or metastatic biliary tract cancer were sequentially enrolled and treated at one centre in Austria. All patients received intravenous infusions of 500 mg/m(2) cetuximab on day 1, 1000 mg/m(2) gemcitabine on day 1, and 100 mg/m(2) oxaliplatin on day 2, every 2 weeks for 12 cycles. The primary outcome was overall response rate. Analysis was by intention to treat. Adverse reactions were assessed according to National Cancer Institute Common Toxicity Criteria. The study is completed and registered with ClinicalTrials.gov, number NCT01216345.

FINDINGS

30 patients with median age of 68 years (IQR 62-73) were enrolled and included in the analysis. Objective response occurred in 19 patients (63%; 95% CI 56·2-69·8), of whom three (10%; 3·2-16·8) achieved complete response, and 16 (53%; 46·2-59·8) achieved partial response. Nine patients underwent potentially curative secondary resection after major response to therapy. Grade 3 adverse events were recorded in 13 patients: skin rash (n=4), peripheral neuropathy (n=4), thrombocytopenia (n=3), nausea (n=1), diarrhoea (n=1), and neutropenia (n=1); no grade 4 adverse events were recorded.

INTERPRETATION

Cetuximab plus GEMOX was well tolerated and had encouraging antitumour activity, leading to secondary resection in a third of patients. These findings warrant further study of cetuximab plus GEMOX in a large randomised trial.

Nedd4L modulates the transcription of metalloproteinase-1 and -13 genes to increase the invasive activity of gallbladder cancer

The aim of this study was to examine whether Nedd4L (neural precursor cell expressed, developmentally down-regulated 4-like) participated in gallbladder carcinogenesis. We first immunohistochemically examined the expression of Nedd4L in various gallbladder tissue specimens. Weak immunoreactivity to Nedd4L-specific antibody was observed in normal or dysplastic epithelial cells. Cancer cells in non-invasive regions exhibited little immunoreactivity, whereas strong immunostaining was found in cytoplasm of many invasive cancers, especially at cancer invasive front with desmoplastic reaction. Notably, siRNA-mediated silencing of the Nedd4L gene significantly decreased the Matrigel-invasion activity and collagen invasion activity of cultured gallbladder cancer cells, without affecting the cell growth. The subtractive mRNA hybridization followed by RT-PCR and immunoblotting revealed that down-regulation of Nedd4L significantly decreased the expression of collagenases, matrix metalloproteinase (MMP)-1 and -13, in gallbladder cancer cells. Finally, immunohistochemical staining showed that many Nedd4L-expressing invasive gallbladder cancer cells co-expressed MMP-1 and MMP-13. These results indicated that over-expression of Nedd4L might lead to gallbladder cancer invasion by regulating the transcription of the MMP-1 and MMP-13 genes.

Characterization of a novel oncogenic K-ras mutation in colon cancer

Activating mutations of RAS are frequently observed in subsets of human cancers, indicating that RAS activation is involved in tumorigenesis. Here, we identified and characterized a novel G to T transversion mutation of the K-ras gene at the third position of codon 19 (TTG) which substituted phenylalanine for leucine in 3 primary colon carcinomas. Biological and biochemical activity was examined using transformed NIH3T3 cells expressing mutant or wild-type K-ras. Transformants harboring the K-ras mutation at codon 19 showed proliferative capacity under serum-starved conditions, less contact inhibition, anchorage-independent growth, tumorigenicity in nude mice and elevation of active Ras-GTP levels. These results indicated that this novel mutation possesses high oncogenic activity.

Promoter hypermethylation of the p16 gene and loss of its protein expression is correlated with tumor progression in extrahepatic bile duct carcinomas

CONTEXT

The p16 gene is one of the tumor suppressor genes, and its inactivation results in abnormal regulation of the cell cycle in human neoplasms. Promoter hypermethylation, a mechanism of p16 gene inactivation, has been reported to play an important role in tumorigenesis and to be related to patient prognosis in several carcinomas.

OBJECTIVE

To determine the role of the p16 gene in extrahepatic bile duct (EBD) carcinomas.

DESIGN

We examined promoter hypermethylation of the p16 gene using a methylation-specific polymerase chain reaction and the expression of the p16 protein using an immunohistochemical staining method in 90 cases of EBD carcinomas. We then compared the data with various clinicopathologic parameters, including survival rate.

RESULTS

Promoter hypermethylation was observed in 69 (77%) of the 90 cases. Of 69 hypermethylated cases, 32 (46%) demonstrated loss of p16 expression. Promoter hypermethylation of the p16 gene was more commonly observed in tumors with vascular invasion (22 [92%] of 24 cases) than without vascular invasion (71%, P = .03). Furthermore, p16 promoter hypermethylation with loss of p16 expression was more frequently observed in cases with lymph node metastasis (P = .006) and higher tumor stage group (P = .04). However, there was no significant difference in survival rate according to the status of p16 promoter methylation and/or p16 expression.

CONCLUSION

Promoter hypermethylation is an important mechanism in the inactivation of the p16 gene in EBD carcinogenesis. Furthermore, the loss of p16 expression, with or without p16 gene promoter hypermethylation, is closely related to the tumor progression in EBD carcinomas.

K-ras, p53 mutations, and microsatellite instability (MSI) in gallbladder cancer

Despite the considerable progress in understanding the molecular pathology of carcinogenesis, the genetic mechanisms underlying the development and progression of gallbladder cancer (GC) are poorly understood. The survival of GC patients is generally poor. Therefore, it is very useful to define valuable prognostic factors. The most extensively studied oncogenes in gallbladder carcinogenesis are ras, commonly mutated in neoplasms of the gastrointestinal tract. K-ras oncogene is altered in a subset of gallbladder patients and mainly in those having anomalous junction of the pancreaticobiliary tract. Most of the studies of genetic abnormalities in GC have focused on p53 gene. p53 mutation/overexpression and/or LOH is present in more than 50% of gallbladder carcinomas, suggesting an important role in their pathogenesis. However, these results have not any predictive value yet. Moreover, the involvement of an alternative molecular pathway, that of microsatellite instability (MSI), is found in a limited group of GC patients. Additional research is necessary to establish its possible relation to defects of the mismatch repair (MMR) system and its proposed prognostic significance. Further elucidation of the molecular events specific to GC will help to identify novel molecular targets for the diagnosis and clinical management of the patients.

Neuroendocrine differentiation in extrahepatic bile duct carcinomas and its prognostic significance

Neuroendocrine differentiation is known to be one of the prognostic factors in many carcinomas. However, the characteristics of neuroendocrine differentiation are not well elucidated in extrahepatic bile duct (EBD) carcinomas. One hundred ninety-four cases of EBD carcinomas were analyzed using immunohistochemistry with synaptophysin and chromogranin. The tumors were graded as degree 0, 1, and 2 when the positive tumor cells were 5% or less, 6% to 25%, and 26% or more, respectively. Immunohistochemical results were compared with clinicopathologic variables and survival rate. Synaptophysin and chromogranin were positive in 54 (27.8%) and 74 (38.1%) cases, respectively. Thirty-four cases (17.5%) were positive for both synaptophysin and chromogranin, 20 (10.3%) and 40 cases (20.6%) were positive only for synaptophysin and for chromogranin, respectively, and 100 cases (51.6%) were negative for both markers. There was a significant survival difference between overall synaptophysin-positive (median, 27 months) and synaptophysin-negative (38 months) groups (P < .05). However, there was no survival difference between chromogranin-positive and chromogranin-negative groups. There was a significant survival difference between the dual-positive expression to synaptophysin and chromogranin group (median, 21 months) and the dual-negative expression group (median, 35 months; P < .05). In summary, synaptophysin expression was an important prognostic factor because synaptophysin-positive cases showed a worse prognosis than synaptophysin-negative cases. The more tumor cells expressed chromogranin, the poorer the survival. Therefore, immunohistochemical studies for neuroendocrine differentiation may be helpful in routine pathological examinations for evaluating the survival and the prognosis of patients with EBD carcinomas.

The Wnt pathway is active in a small subset of pancreas cancer cell lines

Activation of the Wnt pathway plays an important role in the development of a wide variety of tumor types. Two genes involved in the activation of this pathway in tumors are Adenomatous Polyposis Coli (APC) and beta-catenin. Here, we analyze the activity of the Wnt pathway in cultured cells derived from ductal and acinar pancreatic adenocarcinomas using a reporter assay dependent on the activity of the beta-catenin/Tcf4 complex. We find that low-level Wnt activity can be detected in several pancreas cancer lines. High levels of reporter activity were detected exclusively in RWP-1 cells. These cells display nuclear beta-catenin and express a truncated APC protein resulting from a CAA>TAA mutation (Q1303X). Expression of a dominant negative Tcf4 protein inhibited proliferation of RWP-1 cells but not in other lines lacking beta-catenin-dependent reporter activity, supporting the functional relevance of this mutation. Our findings indicate that activation of the Wnt pathway may play a role in a small subset of ductal pancreatic cancers. Alternatively, RWP-1 cells may have been derived from a tumor arising in a structure adjacent to the pancreas such as the biliary tract or the Ampulla of Vater. Additional studies on the role of Wnt pathway components in the development/progression of tumors of the peripancreatic region merit consideration.

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

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

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.

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.

A novel activating mutation of the K-ras gene in human primary colon adenocarcinoma

We identified a novel type of point mutation at the 22nd codon of the K-ras gene in a primary colon cancer. The mutation was C to A transversion substituting lysine (AAG) for normal glutamine (CAG) codon. Biological activity of this mutant K-ras gene was tested by expression of full-length cDNA clones in NIH3T3 cells. Most of the K-ras Lys22-transfected cells exhibited an increased saturation density, a lower serum requirement, and transformed morphology reminiscent to the typical K-ras Val12 transformants. However, the tumorigenicity of K-ras Lys22 transformants in nude mice was significantly less potent than that of K-ras Val12 transformants; only a high copy number transformant produced tumors. Even though the activation is incomplete, the finding that the majority of tumor cells in the specimen carried the K-ras Lys22 mutation suggests that this mutation might be advantageous for growth of tumor cells in vivo.

Aberrations of the K-ras, p53, and APC genes in extrahepatic bile duct cancer

BACKGROUND AND OBJECTIVES

The genetic alterations involved in extrahepatic bile duct (EHBD) cancer are poorly understood. Our aim was to identify aberrations of the K-ras, p53, and APC genes in EHBD cancer.

METHODS

We investigated aberrations of these genes in 52 EHBD cancers using polymerase chain reaction (PCR) single-strand conformation polymorphism analysis, followed by direct sequence determination and a PCR restriction fragment length polymorphism assay.

RESULTS

The K-ras, p53, and APC genes were mutated in 9.6%, 32.7%, and 0% of EHBD cancers, respectively. Loss of heterozygosity at the p53 and APC gene loci was identified in 15.6% and 38.5% of EHBD cancers, respectively.

CONCLUSIONS

Our results suggest that an unknown suppressor gene on 5q other than the APC gene may be responsible for EHBD cancer.

Association between coffee drinking and K-ras mutations in exocrine pancreatic cancer. PANKRAS II Study Group

STUDY OBJECTIVE

To analyse the relation between coffee consumption and mutations in the K-ras gene in exocrine pancreatic cancer.

DESIGN

Case-case study. Consumption of coffee among cases with the activating mutation in the K-ras gene was compared with that of cases without the mutation.

SETTING AND PATIENTS

All cases of pancreatic cancer newly diagnosed at five hospitals in Spain during three years were included in the PANKRAS II Study (n = 185, of whom 121 whose tissue was available for molecular analysis are the object of the present report). Over 88% were personally interviewed in hospital. DNA was amplified from paraffin wax embedded tissues, and mutations in codon 12 of K-ras were detected by the artificial RFLP technique.

MAIN RESULTS

Mutations were found in tumours from 94 of 121 patients (77.7%). Mutations were more common among regular coffee drinkers than among non-regular coffee drinkers (82.0% v 55.6%, p = 0.018, n = 107). The odds ratio adjusted by age, sex, smoking and alcohol drinking was 5.41 (95% CI 1.64, 17.78). The weekly intake of coffee was significantly higher among patients with a mutated tumour (mean of 14.5 cups/week v 8.8 among patients with a wild type tumour, p < 0.05). With respect to non-regular coffee drinkers, the odds ratio of a mutated tumour adjusted by age, sex, smoking and alcohol drinking was 3.26 for drinkers of 2-7 cups/week, 5.77 for drinkers of 8-14 cups/week and 9.99 for drinkers of > or = 15 cups/week (p < 0.01, test for trend).

CONCLUSIONS

Pancreatic cancer cases without activating mutations in the K-ras gene had drank significantly less coffee than cases with a mutation, with a significant dose response relation: the less they drank, the less likely their tumours were to harbour a mutation. In exocrine pancreatic cancer the K-ras gene may be activated less often among non-regular coffee drinkers than among regular drinkers. Caffeine, other coffee compounds or other factors with which coffee drinking is associated may modulate K-ras activation.

Choledochal cystic malignancies

Cystic diseases of the bile ducts are rare, but relatively more prevalent in females, and more common in Japan and Asia. Most are diagnosed in children under 10 years of age, with varying patterns of symptoms including right upper quadrant pain, jaundice, and fever. Up to 20% of bile duct cysts are diagnosed in adults, including during pregnancy, in whom the diagnosis can be confounded by associated cholelithiasis, or by abnormalities of the pancreatic junction with pancreatitis. The risk of malignant transformation increases with age, and is more common in cysts of Alonso-Lej Types I, IV, and V (Caroli's Disease). Intracystic lithiasis is frequently associated with tumour, and can give similar radiological appearances. Tumours are often first diagnosed at laparotomy, and can already be unresectable. More than half the tumours are intracystic, but malignant change in cyst mucosa without a tumour mass is often not recognised at surgery. In addition, malignant change in bile duct epithelium can occur after cyst excision, sometimes after many years, and in areas of the biliary tree remote from the cyst, including the gall-bladder. Cyst excision should be attempted at all ages, and patients closely monitored thereafter. Malignancy should be suspected in all adults with bile duct cysts. Hepatectomy, partial or total with transplantation, is the treatment of choice in Caroli's disease.

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

OBJECTIVE

There have been few studies on the molecular biological characteristics of carcinoma of the papilla of Vater. In this study, p53 and p21/Waf1 expression and K-ras codon 12 mutation in carcinoma of the papilla of Vater were investigated.

METHODS

Thirty-seven cases of carcinoma of the papilla of Vater were studied. Macroscopically, the carcinoma was ulcerative in 15 cases and nonulcerative in 22 cases. Histologically, nine were intestinal type, 27 were pancreaticobiliary type, and one was undifferentiated. Formalin-fixed, paraffin-embedded sections were immunohistochemically stained for p53 and p21. K-ras codon 12 mutation was detected with the two-step polymerase chain reaction-restriction fragment length polymorphism method, followed by direct sequencing.

RESULTS

p53 overexpression was found in 17 of 37 cases (46%) and was more frequent in the ulcerative type than in the nonulcerative type (67% vs 32%, p < 0.05). p21/Waf1 protein expression was found in 15 of 37 cases (41%), and was not correlated with that of p53. K-ras codon 12 mutation was found in 14 of 37 cases (38%), and was more frequently detected in the intestinal type than in the pancreaticobiliary type (66% vs 30%, p < 0.05). On direct sequencing, the mutations were mainly GGT to GAT (9/14) and GGT to GTT (4/14). The type of mutation did not correlate with the histological type.

CONCLUSIONS

In carcinoma of the papilla of Vater, p53 overexpression may play a role in tumor ulceration. p21/Waf1 expression is induced via a p53-independent pathway. Carcinomas of the intestinal and pancreaticobiliary types may develop via different mechanisms, and K-ras mutation is mainly associated with the intestinal type.

Carcinoma of the gall-bladder

Carcinoma of the gall-bladder remains the fifth commonest gastrointestinal malignancy. Its associations, predisposing factors and epidemiology worldwide are reviewed in this article. The clinical presentation of carcinoma of the gall-bladder is frequently late, which accounts for the poor prognosis: this is also discussed. The use of relevant imaging techniques and aggressive management offer an improved outlook. These important aspects and others, such as the use of frozen section histology, the risks of trocar seeding and inadequate resection are mentioned.

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.

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.

Bile duct brushings cytology: potential pitfalls in diagnosis

Bile duct brushings (BDB) are the method of choice for pathological diagnosis of malignancy of the hepatobiliary system in our institution. We examined results of the cytological assessment of 267 BDB and compared them with biopsies, which were available in 131 cases. Sensitivity of BDB for diagnosis of malignancy was 44% and specificity 100%, in keeping with the experience of others. The review of "false-negative cases" reveals four main reasons for the relatively modest sensitivity of BDB in diagnosis of malignancy: poor sampling, lack of diagnostic criteria for dysplasia-carcinoma in situ, difficulties in recognition of special tumor types, and underestimating the significance of the smear background. After a critical review and with regard to these issues, the sensitivity of BDB in our series could have been improved to 78%. We conclude that BDB can give a confident and definitive diagnosis of malignancy, which can be relied upon without a tissue biopsy. A negative result does not exclude malignancy.

Ki-ras mutations in exocrine pancreatic cancer: association with clinico-pathological characteristics and with tobacco and alcohol consumption. PANK-ras I Project Investigators

The aims of this study were (i) to assess the prevalence and spectrum of codon 12 Ki-ras mutations in patients diagnosed with exocrine pancreatic cancer (EPC) in 2 general hospitals between 1980 and 1990, (ii) to analyze the association of this genetic alteration with clinical and pathological characteristics, and (iii) to determine the association of Ki-ras mutations with tobacco and alcohol consumption. DNA was amplified from paraffin-embedded tissue samples and mutations in codon 12 of Ki-ras were detected using the artificial RFLP technique. Cox proportional-hazards regression and unconditional logistic regression were applied. Codon 12 Ki-ras mutations were detected in 30 of 51 cases for which molecular results were available. The amino-acid substitutions were Asp (8), Val (6), and Arg (3). A double mutation, including always a Val, was detected in 5 cases. None of the 4 nonductal pancreatic neoplasms were mutated. The mutation prevalence was 79% in metastases and 54% in primary tumors. The risk of a mutated tumor was 3 times higher in alcohol drinkers than in non-drinkers, and a linear trend was apparent. When age, gender, hospital, and tobacco and alcohol consumption were taken into account, a high risk for mutations was detected in patients who only smoked and in patients who only drank, but less so in patients who both smoked and drank. These results raise novel hypotheses regarding the role of tobacco and alcohol in EPC.