Mutational profiling reveals PIK3CA mutations in gallbladder carcinoma

Multigene mutational profiling of cholangiocarcinomas identifies actionable molecular subgroups

One-hundred-fifty-three biliary cancers, including 70 intrahepatic cholangiocarcinomas (ICC), 57 extrahepatic cholangiocarcinomas (ECC) and 26 gallbladder carcinomas (GBC) were assessed for mutations in 56 genes using multigene next-generation sequencing. Expression of EGFR and mTOR pathway genes was investigated by immunohistochemistry. At least one mutated gene was observed in 118/153 (77%) cancers. The genes most frequently involved were KRAS (28%), TP53 (18%), ARID1A (12%), IDH1/2 (9%), PBRM1 (9%), BAP1 (7%), and PIK3CA (7%). IDH1/2 (p=0.0005) and BAP1 (p=0.0097) mutations were characteristic of ICC, while KRAS (p=0.0019) and TP53 (p=0.0019) were more frequent in ECC and GBC. Multivariate analysis identified tumour stage and TP53 mutations as independent predictors of survival. Alterations in chromatin remodeling genes (ARID1A, BAP1, PBRM1, SMARCB1) were seen in 31% of cases. Potentially actionable mutations were seen in 104/153 (68%) cancers: i) KRAS/NRAS/BRAF mutations were found in 34% of cancers; ii) mTOR pathway activation was documented by immunohistochemistry in 51% of cases and by mutations in mTOR pathway genes in 19% of cancers; iii) TGF-ß/Smad signaling was altered in 10.5% cancers; iv) mutations in tyrosine kinase receptors were found in 9% cases. Our study identified molecular subgroups of cholangiocarcinomas that can be explored for specific drug targeting in clinical trials.

Microsatellite instability in gallbladder carcinoma

The genetic abnormalities involved in the pathogenesis of gallbladder carcinoma (GBC) remain unclear. Microsatellite instability (MSI) has been described in many carcinomas, but little is known about the significance of mismatch repair in gallbladder carcinogenesis. Additionally, methylation status of long interspersed element-1 (LINE-1), a surrogate marker of global DNA methylation, has defined distinct subsets of other cancer types but has not been explored in GBC. Immunohistochemical expression of MSH2, MSH6, MLH1, and PMS2 and LINE-1 mRNA in situ hybridization was evaluated in 67 primary and 15 metastatic GBCs from 77 patients. Amplification of human epidermal growth factor receptor 2 (HER2) was evaluated by fluorescence in situ hybridization. Genotyping for 24 genes involved in carcinogenesis was performed using a multiplex PCR-based platform. MSI was present in 6 of 77 GBCs (7.8 %). Loss of MSH2/MSH6 was detected in five cases and loss of MLH1/PMS2 in one case. MSI status was not associated with Lynch syndrome, tumor grade, extracellular mucin, or tumor-infiltrating lymphocytes. There was no significant difference in mean overall survival of patients with and without MSI. Strong LINE-1 staining was identified in none of the GBC with MSI and in 36 of 69 (52 %) of those without MSI (p = 0.005), suggesting that LINE-1 in the former cohort was hypermethylated. All MSI tumors were negative for HER2 amplification, and TP53 and NRAS mutations were only found in GBC without MSI. MSI was identified in a minority of GBC cases. The strong correlation between global DNA methylation as measured by LINE-1 and loss of mismatch repair proteins suggests that methylation may account for the loss of these proteins. These hypermethylated tumors appear to represent a genetically unique cohort of gallbladder neoplasms, and the data suggests that demethylating agents may have a therapeutic value in this class of tumors.

Surgical resection of solid gallbladder adenocarcinoma presenting as a large mass: report of a case

This report describes a case of a patient with a large solid gallbladder adenocarcinoma that was completely resected through aggressive surgery. The patient was a 57-year-old woman who had been diagnosed with advanced gallbladder cancer, had no indications for surgical resection and was scheduled to undergo systemic chemotherapy. She presented to our hospital for a second opinion. At the time of assessment, her tumor was large but was well-localized and had not invaded into the surrounding tissues, indicating that surgical resection was a reasonable option. Subsequently, the tumor was completely extracted via right hepatectomy with en bloc resection of the caudate lobe and extrahepatic bile duct. Histopathologically, the tumor was a solid adenocarcinoma. Although there are relatively few reports in the literature regarding solid gallbladder adenocarcinoma, well-localized growth appears to be a characteristic feature. On the basis of a tumor’s progression behavior, aggressive surgical treatment might be indicated even when the tumor has grown to a considerable size.

Targeting specific molecular pathways holds promise for advanced gallbladder cancer therapy

Gallbladder cancer is the most common and aggressive malignancy of the biliary tract. The complete surgical resection is the only potentially curative approach in early stage; however, most cases are diagnosed in advanced stages and the response to traditional chemotherapy and radiotherapy is extremely limited, with modest impact in overall survival. The recent progress in understanding the molecular alterations of gallbladder cancer has shown great promise for the development of more effective treatment strategies. This has mainly resulted from the identification of molecular alterations in relevant intracellular signaling pathways-Hedgehog, PI3K/AKT/mTOR, Notch, ErbB, MAPK and angiogenesis-which are potential tailored targets for gallbladder cancer patients. This review discusses the recent remarkable progress in understanding the molecular alterations that represent novel prognosis molecular markers and therapeutic targets for gallbladder cancer, which will provide opportunities for research and for developing innovative strategies that may enhance the benefit of conventional chemotherapy, or eventually modify the fatal natural history of this orphan disease.

Epidermal growth factor receptor signaling pathway is frequently altered in ampullary carcinoma at protein and genetic levels

Our objective was to explore alteration of the epidermal growth factor receptor (EGFR) signaling pathway in ampullary carcinoma. Immunohistochemical studies were employed to evaluate expression of amphiregulin as well as expression and activation of EGFR. A lab-developed assay was used to identify mutations in the EGFR pathway genes, including KRAS, BRAF, PIK3CA, PTEN, and AKT1. A total of 52 ampullary carcinomas were identified, including 25 intestinal-type and 24 pancreatobiliary-type tumors, with the intestinal type being associated with a younger age at diagnosis (P=0.03) and a better prognosis (P<0.01). Expression of amphiregulin correlated with better differentiation (P<0.01), but no difference was observed between two major histologic types. Expression and activation of EGFR was more commonly seen in the pancreatobiliary type (P<0.01). Mutations were detected in 50% of the pancreatobiliary type and 60% of the intestinal type. KRAS was the most common gene mutated in the pancreatobiliary type (42%) as well as the intestinal type (52%). Other mutations detected included PIK3CA, SMAD4 and BRAF. KRAS mutations at codons 12 and 13 did not adversely affect overall survival. In conclusion, EGFR expression and activation were different between intestinal- and pancreatobiliary-type ampullary carcinoma. KRAS mutation was common in both histologic types; however, the incidence appeared to be lower in the pancreatobiliary type compared with its pancreatic counterpart, pancreatic ductal adenocarcinoma. Mutational analysis of the EGFR pathway genes may provide important insights into personalized treatment for patients with ampullary carcinoma.

High throughput molecular profiling reveals differential mutation patterns in intrahepatic cholangiocarcinomas arising in chronic advanced liver diseases

Intrahepatic cholangiocarcinomas occur mostly in the normal liver but they also arise in chronic advanced liver diseases. However, genetic differences between two groups have yet to be examined. High throughput mass spectrometry-based platform was used to interrogate mutations in intrahepatic cholangiocarcinomas and to compare the mutation profiles between 43 intrahepatic cholangiocarcinomas with normal liver and 38 with chronic advanced liver diseases. Forty seven mutations in 11 genes were identified in 38 of 81 cases (46.9%). The most commonly mutated gene was KRAS (11/81, 13.6%), followed by MLH1 (7/81, 8.6%), NRAS (7/81, 8.6%), GNAS (6/81, 7.4%), and EGFR (6/81, 7.4%). BRAF, APC, PIK3CA, CDKN2A, PTEN, and TP53 mutations were found with less than 5%. Overall mutation rate of intrahepatic cholangiocarcinomas with chronic advanced liver disease (15/38, 39.5%, 95% confidence interval: 23.9-55.0) was lower than that of intrahepatic cholangiocarcinomas with normal liver (23/43, 53.5%, 95% confidence interval: 38.5-68.3). Intrahepatic cholangiocarcinomas with chronic advanced liver disease showed higher EGFR mutation rate (5/38, 13.2% vs 1/43, 2.3%) and lower mutation rates of KRAS (3/38, 7.9% vs 8/43, 18.6%), MLH1 (2/38, 5.3% vs 5/43, 11.6%), and GNAS (1/38, 2.6% vs 5/43, 11.6%), compared with those in intrahepatic cholangiocarcinomas with normal liver. Mutations in PIK3CA, PTEN, CDKN2A, and TP53 were harbored only in intrahepatic cholangiocarcinomas with normal liver. KRAS (P=0.0075) or GNAS mutations (P=0.0256) were associated with poor overall survival in all patients with intrahepatic cholangiocarcinoma. Differential mutation patterns of intrahepatic cholangiocarcinomas with chronic advanced liver disease suggest different cholangiocarcinogenesis depending upon the predisposing factors, and support that different strategy for targeted therapy should be applied in intrahepatic cholangiocarcinoma subtypes.

Capsaicin treatment attenuates cholangiocarcinoma carcinogenesis

Capsaicin, the most abundant pungent molecule produced by pepper plants, represents an important ingredient in spicy foods consumed throughout the world. Studies have shown that capsaicin can relieve inflammation and has anti-proliferative effects on various human malignancies. Cholangiocarcinoma (CC) is a cancer disease with rising incidence. The prognosis remains dismal with little advance in treatment. The aim of the present study is to explore the anti-tumor activity of capsaicin in cultured human CC cell lines. Capsaicin effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. Further, we show that capsaicin treatment of CC cells regulates the Hedgehog signaling pathway.

CONCLUSION

Our results provide a basis for capsaicin to improve the prognosis of CCs in vivo and present new insights into the effectiveness and mode of action of capsaicin.

Integrated genomic characterization reveals novel, therapeutically relevant drug targets in FGFR and EGFR pathways in sporadic intrahepatic cholangiocarcinoma

Advanced cholangiocarcinoma continues to harbor a difficult prognosis and therapeutic options have been limited. During the course of a clinical trial of whole genomic sequencing seeking druggable targets, we examined six patients with advanced cholangiocarcinoma. Integrated genome-wide and whole transcriptome sequence analyses were performed on tumors from six patients with advanced, sporadic intrahepatic cholangiocarcinoma (SIC) to identify potential therapeutically actionable events. Among the somatic events captured in our analysis, we uncovered two novel therapeutically relevant genomic contexts that when acted upon, resulted in preliminary evidence of anti-tumor activity. Genome-wide structural analysis of sequence data revealed recurrent translocation events involving the FGFR2 locus in three of six assessed patients. These observations and supporting evidence triggered the use of FGFR inhibitors in these patients. In one example, preliminary anti-tumor activity of pazopanib (in vitro FGFR2 IC₅₀≈350 nM) was noted in a patient with an FGFR2-TACC3 fusion. After progression on pazopanib, the same patient also had stable disease on ponatinib, a pan-FGFR inhibitor (in vitro, FGFR2 IC₅₀≈8 nM). In an independent non-FGFR2 translocation patient, exome and transcriptome analysis revealed an allele specific somatic nonsense mutation (E384X) in ERRFI1, a direct negative regulator of EGFR activation. Rapid and robust disease regression was noted in this ERRFI1 inactivated tumor when treated with erlotinib, an EGFR kinase inhibitor. FGFR2 fusions and ERRFI mutations may represent novel targets in sporadic intrahepatic cholangiocarcinoma and trials should be characterized in larger cohorts of patients with these aberrations.

Cholangiocarcinoma is a cancer that affects the bile ducts. Unfortunately, many patients diagnosed with cholangiocarcinoma have disease that cannot be treated with surgery or has spread to other parts of the body, thus severely limiting treatment options. New advances in drug treatment have enabled treatment of these cancers with “targeted therapy” that exploits an error in the normal functioning of a tumor cell, compared to other cells in the body, thus allowing only tumor cells to be killed by the drug. We sought to identify changes in the genetic material of cholangiocarcinoma patient tumors in order to identify potential errors in cellular functioning by utilizing cutting edge genetic sequencing technology. We identified three patient tumors possessing an FGFR2 gene that was aberrantly fused to another gene. Two of these patients were able to receive targeted therapy for FGFR2 with resulting tumor shrinkage. A fourth tumor contained an error in a gene that controls a very important cellular mechanism in cancer, termed epidermal growth factor pathway (EGFR). This patient received therapy targeting this mechanism and also demonstrated response to treatment. Thus, we have been able to utilize cutting edge technology with targeted drug treatment to personalize medical treatment for cancer in cholangiocarcinoma patients.

A perspective on molecular therapy in cholangiocarcinoma: present status and future directions

Cholangiocarcinoma (CCA) is an orphan cancer with limited understanding of its genetic and genomic pathogenesis. Typically, it is highly treatment-refractory and patient outcome is dismal. Currently, there are no approved therapeutics for CCA and surgical resection remains the only option with curative intent. Clinical trials are currently being performed in a mixed cohort of biliary tract cancers that includes intrahepatic CCA, extrahepatic/perihilar CCA, distal extrahepatic CCA, gallbladder carcinoma and, in rare cases, even pancreatic cancers. Today, clinical trials fail primarily because they are underpowered mixed cohorts and designed without intent to enrich for markers to optimize success for targeted therapy. This review aims to emphasize current clinical attempts for targeted therapy of CCA, as well as highlight promising new candidate pathways revealed by translational genomics.

New and emerging treatment options for biliary tract cancer

Biliary tract cancer (BTC) is a group of relatively rare tumors with a poor prognosis. The current standard of care consists of doublet chemotherapy (platinum plus gemcitabine); however, even with cytotoxic therapy, the median overall survival is less than 1 year. The genetic basis of BTC is now more clearly understood, allowing for the investigation of targeted therapy. Combinations of doublet chemotherapy with antiepidermal growth factor receptor agents have provided modest results in Phase II and Phase III setting, and responses with small molecule inhibitors are limited. Moving forward as we continue to characterize the genetic hallmarks of BTC, a stepwise, strategic, and cooperative approach will allow us to make progress when developing new treatments.

Activation of Notch signaling is required for cholangiocarcinoma progression and is enhanced by inactivation of p53 in vivo

Cholangiocacinoma (CC) is a cancer disease with rising incidence. Notch signaling has been shown to be deregulated in many cancers. However, the role of this signaling pathway in the carcinogenesis of CC is still not fully explored. In this study, we investigated the effects of Notch inhibition by γ-secretase inhibitor IX (GSI IX) in cultured human CC cell lines and we established a transgenic mouse model with liver specific expression of the intracellular domain of Notch (Notch-ICD) and inactivation of tumor suppressor p53. GSI IX treatment effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. In vivo overexpression of Notch-ICD together with an inactivation of p53 significantly increased tumor burden and showed CC characteristics. Conclusion: Our study highlights the importance of Notch signaling in the tumorigenesis of CC and demonstrates that additional inactivation of p53 in vivo.

State-of-the-art in the management of locally advanced and metastatic gallbladder cancer

PURPOSE OF REVIEW

Gallbladder carcinoma (GBC), classified as a biliary tract cancer (BTC) along with intrahepatic and extrahepatic cholangiocarcinomas, is a rare disease in Western countries, but a highly prevalent disease in Chile, other countries in Latin America, India and Japan. It commonly presents at an advanced stage, and has limited therapeutic options. Cisplatin/gemcitabine has emerged as the first-line standard of care for patients with advanced BTCs, but the prognosis remains poor. Development of molecularly targeted therapies in advanced BTC remains challenging.

RECENT FINDINGS

Comprehension of the molecular events in gallbladder carcinogenesis may provide a novel targeted therapeutic approach, and early stage clinical trials with targeted therapies appear promising, although the relationship between subsets of patients with positive responses to therapy and tumor genetics requires further exploration. Recent developments in targeted therapeutics, directed against several key signalling pathways in BTC, including epidermal growth factor receptor, angiogenesis, and the mitogen-activated protein kinase pathway will be discussed, in addition to the potential application of prognostic factors and markers.

SUMMARY

The future therapeutic spectrum for BTC and GBC will likely encompass novel combinations of targeted therapies with cytostatics in scientifically and molecularly directed schedules, thus permitting fewer mechanisms of escape for tumor cells.

Intrahepatic cholangiocarcinoma: pathogenesis and rationale for molecular therapies

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy with very poor prognosis. Genome-wide, high-throughput technologies have made major advances in understanding the molecular basis of this disease, although important mechanisms are still unclear. Recent data have revealed specific genetic mutations (for example, KRAS, IDH1 and IDH2), epigenetic silencing, aberrant signaling pathway activation (for example, interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3), tyrosine kinase receptor-related pathways) and molecular subclasses with unique alterations (for example, proliferation and inflammation subclasses). In addition, some ICCs share common genomic traits with hepatocellular carcinoma. All this information provides the basis to explore novel targeted therapies. Currently, surgery at early stage is the only effective therapy. At more advanced stages, chemotherapy regimens are emerging (that is, cisplatin plus gemcitabine), along with molecular targeted agents tested in several ongoing clinical trials. Nonetheless, a first-line conclusive treatment remains an unmet need. Similarly, there are no studies assessing tumor response related with genetic alterations. This review explores the recent advancements in the knowledge of the molecular alterations underlying ICC and the future prospects in terms of therapeutic strategies leading towards a more personalized treatment of this neoplasm.

Current therapy and future directions in biliary tract malignancies

OPINION STATEMENT

Cancers of the biliary tree represent a rare group of diseases with a devastating impact on patients. Gallbladder cancer often is associated with cholelithiasis. Cholangiocarcinoma may arise in the setting of biliary inflammation, such as primary sclerosing cholangitis, but most commonly occurs in patients without a particular risk factor. Surgical removal of biliary cancer is essential for cure, but it is associated with a very high rate of recurrence and for many patients is not possible at the time of diagnosis. Although risk factors differ for each anatomic site, systemic treatment is generally similar. Various adjunctive therapies, such as radiation and embolization, have been investigated for biliary tract cancers with modest success and efforts are ongoing to understand how to optimize these tools. Retrospective series and pooled analysis suggest a benefit for adjuvant treatment following resection, but prospective data are limited. Ongoing and planned phase 3 trials should help to clarify the role of adjuvant chemotherapy and radiation. For advanced disease, chemotherapy improves quality of life and survival, and gemcitabine with cisplatin represents the standard of care. However, all patients ultimately progress on this therapy, so clinical trials of new and better agents are essential to expand the existing treatment options for patients.

Inhibition of hedgehog signaling attenuates carcinogenesis in vitro and increases necrosis of cholangiocellular carcinoma

The Hedgehog signaling pathway plays a pivotal role during embryonic development, stem cell maintenance, and wound healing. Hedgehog signaling also is deregulated in many cancers. However, the role of this signaling pathway in the carcinogenesis of cholangiocarcinoma (CCC) is still unknown. In this study, we investigated the effects of Hedgehog inhibition by cyclopamine and 5E1 in cultured human CCC cell lines and in vivo using a xenograft mouse model. We also investigated the involvement of Hedgehog in epithelial to mesenchymal transition (EMT), migration, and CCC tumor growth. Sonic hedgehog (Shh) ligand was highly expressed in 89% of human CCC tissues and in CCC cell lines. Cyclopamine and 5E1 treatments effectively inhibited cell proliferation, migration, and invasion by down-regulating the Hedgehog target genes glioblastoma 1 and glioblastoma 2. In vitro and in vivo, we detected an increase in epithelial marker, E-cadherin, after Hedgehog inhibition. In addition, we saw an increase in necrotic areas and a decrease in mitotic figures in cyclopamine and 5E1-treated CCC xenograft tumors.

CONCLUSION

This study supports the presence of autocrine Hedgehog signaling in human CCC, where CCC cells produce and respond to Shh ligand. Blocking the Hedgehog pathway inhibited EMT and decreased the viability of CCC cells. In addition, cyclopamine and 5E1 inhibited the growth of CCC xenograft tumors.

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.

Targeted therapy of advanced gallbladder cancer and cholangiocarcinoma with aggressive biology: eliciting early response signals from phase 1 trials

PURPOSE

Patients with advanced cholangiocarcinoma (CC) and gallbladder carcinoma (GC) have few therapeutic options for relapsed disease. methods: Given the overall poor prognosis in this population and the availability of novel targeted therapies, we systematically analyzed the characteristics and outcomes for GC and CC patients treated on phase I trials with an emphasis on targeted agents and locoregional therapies.

RESULTS

Of 40 treated patients (GC=6; CC=34; median age, 60 years), 8 (20%) had stable disease (SD) > 6 months, 3 (8%) partial response (PR), on protocols with hepatic arterial drug infusion and anti-angiogenic, anti-HER-2/neu or novel MAPK/ERK kinase (MEK) inhibitors. Median progression-free survival (PFS) on phase I trials was 2.0 months (95% CI 1.7, 2.8) versus 3.0 months (95% CI 2.4, 5.0), 3.0 months (95% CI 2.3, 4.6), and 3.0 months (95% CI 2.4, 3.9) for their first-, second-, and last-line FDA-approved therapy. In univariate analysis, >3 metastatic sites, elevated alanine aminotransferase (ALT) (>56IU/L), serum creatinine (>1.6mg/dL), and CA19-9 (>35U/mL) were associated with a shorter PFS. Mutational analysis revealed mutation in the KRAS oncogene in 2 of 11 patients (18%). The SD >6 months/PR rate of 28% was seen with hepatic arterial infusion of oxaliplatin, and inhibitors of angiogenesis, HER-2/neu or MEK.

CONCLUSIONS

The PFS in phase I trials was similar to that of the first, second, and last-line therapy (P=0.95, 0.98, 0.76, respectively) with FDA-approved agents given in the advanced setting, emphasizing a role for targeted agents in a clinical trials setting as potentially valuable therapeutic options for these patients.

Advances in the management of biliary tract cancers

Biliary tract cancers, although uncommon, are highly fatal malignancies. Current treatments fail to cure or control the majority of tumors. Given the complexity of the anatomy and the often aggressive nature of the disease, multidisciplinary treatment, including palliation, is often required. However, systemic therapy with cytotoxics and/or targeted agents is routinely the mainstay of treatment for patients with advanced biliary tract cancers, and new targets and agents provide hope for this disease. This article focuses on recent advances in the management of biliary tract cancers, with a special focus on the molecular basis for current therapeutic investigation in this disease.

Regional differences in gallbladder cancer pathogenesis: insights from a comparison of cell cycle-regulatory, PI3K, and pro-angiogenic protein expression

BACKGROUND

The variable incidence of gallbladder cancer (GBCA) suggests regional pathogenetic differences. This study compares cell cycle-regulatory, angiogenesis-related, and PI3K pathway protein expression in GBCAs from three continents.

METHODS

Immunohistochemical expression of several proteins was assessed, correlated with clinicopathologic variables, and compared among centers from Chile (Fundación Arturo López Pérez [FALP]), Japan (Yokohama City University [YCU]), and the United States (Memorial Sloan-Kettering Cancer Center [MSKCC]). Hierarchical clustering was used to partition the data based on protein-expression and treatment center.

RESULTS

Tissue from 117 patients (MSKCC = 76; FALP = 22; YCU = 19) was analyzed. Mdm2 overexpression was seen only at MSKCC (p < 0.0001). Absence of p21 (p = 0.03) and VEGFR2 (p = 0.018) were more common and p27 expression was less frequent (p = 0.047) in tumors from YCU. Ki-67 labeling index in YCU tumors (median = 10) was two-thirds lower than at other centers. On hierarchical clustering analysis, all YCU patients (p = 0.017) and those with early tumors (p = 0.017) clustered separately from MSKCC. Median disease-specific survival after curative intent (R0) resection was 27 months and was similar among centers (p = 0.9). Median disease-specific survival of patients with early tumors was 28.4 months and was higher at YCU (not reached, p = 0.06).

CONCLUSIONS

Cell cycle-regulatory protein expression patterns of YCU tumors differed from those treated at FALP and MSKCC. The differential clustering of protein expression and survival in patients with early tumors suggest regional differences in pathogenesis and disease biology.

High throughput mass spectrometry-based mutation profiling of primary uveal melanoma

PURPOSE

We assessed for mutations in a large number of oncogenes and tumor suppressor genes in primary uveal melanomas using a high-throughput profiling system.

METHODS

DNA was extracted and purified from 134 tissue samples from fresh-frozen tissues (n = 87) or formalin-fixed, paraffin-embedded tissues (n = 47) from 124 large uveal melanomas that underwent primary treatment by enucleation. DNA was subjected to whole genome amplification and MALDI-TOF mass spectrometry-based mutation profiling (>1000 mutations tested across 120 oncogenes and tumor suppressor genes) using the OncoMap3 platform. All candidate mutations, as well as commonly occurring mutations in GNAQ and GNA11, were validated using homogeneous mass extension (hME) technology.

RESULTS

Of 123 samples, 97 (79%, representing 89 unique tumors) were amplified successfully, passed all quality control steps, and were assayed with the OncoMap platform. A total of 58 mutation calls was made for 49 different mutations across 26 different genes in 34/98 (35%) samples. Of 91 tumors that underwent hME validation, 83 (91%) harbored mutations in the GNAQ (47%) or GNA11 (44%) genes, while hME validation revealed two tumors with mutations in EGFR. These additional mutations occurred in tumors that also had mutations in GNAQ or GNA11.

CONCLUSIONS

The vast majority of primary large uveal melanomas harbor mutually-exclusive mutations in GNAQ or GNA11, but very rarely have the oncogenic mutations that are reported commonly in other cancers. When present, these other mutations were found in conjunction with GNAQ/GNA11 mutations, suggesting that these other mutations likely are not the primary drivers of oncogenesis in uveal melanoma.

Molecular biology of gallbladder cancer: potential clinical implications

Gallbladder cancer (GBC) is a common malignancy of the biliary tract and involves the changes in multiple oncogenes and multiple genetic genes. Since over the past decade there has been an advance in the knowledge of the genetic basis of cancer, mainly as a result of the rapid progression of molecular technology; however, conventional therapeutic approaches have not had much impact on the course of this aggressive neoplasm. Knowledge of the molecular biology of GBC is rapidly growing. Genetic alterations in GBC include adenosine triphosphate-binding cassette transporter ABCG8, membrane-bound enzyme ADAM-17 of multi-functional gene family, and other genes including p53, COX2, XPC, and RASSF1A. The advances in molecular biology have potential implications for the detection of this disease, using Synuclein-gamma, Syndecan-1, glycoprotein 72 (TAG-72), tumor endothelial marker 8 protein (TEM8) and TNF-alpha. The use of these molecular diagnostic methods is of clinical importance for the gene replacement therapy, genetic prodrug activation therapy, and antisense immunology technology for the treatment of malignancy. The author reviewed recent publications on PubMed, and summarized molecular biology of GBC, with an emphasis on features of potential clinical implications for diagnosis and management.

Kras(G12D) and p53 mutation cause primary intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (IHCC) is a primary cancer of the liver with an increasing incidence and poor prognosis. Preclinical studies of the etiology and treatment of this disease are hampered by the relatively small number of available IHCC cell lines or genetically faithful animal models. Here we report the development of a genetically engineered mouse model of IHCC that incorporates two of the most common mutations in human IHCC, activating mutations of Kras (Kras(G12D)) and deletion of p53. Tissue-specific activation of Kras(G12D) alone resulted in the development of invasive IHCC with low penetrance and long latency. Latency was shortened by combining Kras(G12D) activation with heterozygous or homozygous deletion of p53 (mean survival of 56 weeks vs. 19 weeks, respectively), which also resulted in widespread local and distant metastasis. Serial analysis showed that the murine models closely recapitulated the multistage histopathologic progression of the human disease, including the development of stroma-rich tumors and the premalignant biliary lesions, intraductal papillary biliary neoplasms (IPBN), and Von Meyenburg complexes (VMC; also known as biliary hamartomas). These findings establish a new genetically and histopathologically faithful model of IHCC and lend experimental support to the hypothesis that IPBN and VMC are precursors to invasive cancers.

Frequent mutation of isocitrate dehydrogenase (IDH)1 and IDH2 in cholangiocarcinoma identified through broad-based tumor genotyping

Cancers of origin in the gallbladder and bile ducts are rarely curable with current modalities of cancer treatment. Our clinical application of broad-based mutational profiling for patients diagnosed with a gastrointestinal malignancy has led to the novel discovery of mutations in the gene encoding isocitrate dehydrogenase 1 (IDH1) in tumors from a subset of patients with cholangiocarcinoma. A total of 287 tumors from gastrointestinal cancer patients (biliary tract, colorectal, gastroesophageal, liver, pancreatic, and small intestine carcinoma) were tested during routine clinical evaluation for 130 site-specific mutations within 15 cancer genes. Mutations were identified within a number of genes, including KRAS (35%), TP53 (22%), PIK3CA (10%), BRAF (7%), APC (6%), NRAS (3%), AKT1 (1%), CTNNB1 (1%), and PTEN (1%). Although mutations in the metabolic enzyme IDH1 were rare in the other common gastrointestinal malignancies in this series (2%), they were found in three tumors (25%) of an initial series of 12 biliary tract carcinomas. To better define IDH1 and IDH2 mutational status, an additional 75 gallbladder and bile duct cancers were examined. Combining these cohorts of biliary cancers, mutations in IDH1 and IDH2 were found only in cholangiocarcinomas of intrahepatic origin (nine of 40, 23%) and in none of the 22 extrahepatic cholangiocarcinomas and none of the 25 gallbladder carcinomas. In an analysis of frozen tissue specimens, IDH1 mutation was associated with highly elevated tissue levels of the enzymatic product 2-hydroxyglutarate. Thus, IDH1 mutation is a molecular feature of cholangiocarcinomas of intrahepatic origin. These findings define a specific metabolic abnormality in this largely incurable type of gastrointestinal cancer and present a potentially new target for therapy.