Expression and clinical significance of the G1-S modulators in intrahepatic cholangiocellular carcinoma

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.

Inverse correlation of aberrant expression of fragile histidine triad (FHIT) protein with cyclin D1 protein and prognosis in Chinese patients with cholangiocarcinoma

BACKGROUND

This is the first study to explore the relationship between the expression of fragile histidine triad, FHIT and cyclin D1 proteins, and the clinicopathological significance of the two proteins in Chinese patients with cholangiocarcinoma.

MATERIAL AND METHODS

Immunohistochemistry was used to study 53 cases of cholangiocarcinoma, 30 para-neoplastic and 20 normal bile ducts for their expression status of FHIT and cyclin D1 and then the results were analyzed with the patient's age, sex, tumour site, histological grade and clinical stage as well as overall median survival time.

RESULTS

Compared with the para-neoplastic and normal cholangiocytes, the expression of FHIT was obviously decreased (p=0.0001), whereas that of cyclin D1 was significantly increased (p=0.0001) in carcinoma cells. The expression of FHIT was found to be correlated with the histological grade (p=0.007) and the clinical stage (p=0.004), but not with age (p=0.776), sex (p=0.246) or tumour site (p=0.347). The expression of cyclin D1 was also showed statistically associated with the histological grade (p=0.043) and clinical stage (p=0.047), but not with age (p=0.965), sex (p=0.751) or tumour site (p=0.948). Further, the expression of FHIT was found to be inversely correlated with the expression of cyclin D1 (p=0.0001). The loss of expression of FHIT and the expression of cyclin D1 were significantly related to the cancers with shorter median survival time (p=0.0001, p=0.0081). The expression of FHIT was an independent prognostic factor (p=0.005).

DISCUSSION

The expression of FHIT may be inversely correlated with the expression of cyclin D1. It is suggested that the loss of FHIT protein and overexpression of cyclin D1 protein may play an important role in carcinogenesis and prognosis of cholangiocarcinoma.

Expression and clinical significance of cell cycle regulatory proteins in gallbladder and extrahepatic bile duct cancer

Disruption of cell cycle controls is a pathognomonic feature of all malignant cells. Therefore, we immunohistochemically investigated the relationship between cell cycle regulatory proteins and clinicopathologic features in order to identify the biomarkers related to the outcome of patients with biliary tract cancer (BTC). A cohort of paraffin-embedded specimens were selected from 36 patients, including 18 gallbladder and 18 extrahepatic bile duct cancers, who underwent curative or palliative surgical resection at Korea University Medical Center from June 1998 to December 2004. Tissue microarrays were used to investigate the immunohistochemical staining for p21, p27, p53, cyclin D1, bcl2, and Ki-67. Univariate and multivariate survival analyses were performed to determine the prognostic significance of each protein expression. Absence of p21 expression independently predicted poor outcome in all cases. Well-differentiated tumor was found to be an independent good prognostic factor in gallbladder cancer. Absence of p21 expression and moderately to poorly differentiated tumor were found to be an independent poor prognostic factor in patients with negative for neural invasion. Absence of p21 and bcl2 were found to be an independent poor prognostic factor in patients with no lymph node metastasis. Absence of p21 expression was a significant independent poor prognostic factor in BTC, partly in patients with biologically less aggressive phenotypes. This finding suggests that determination of p21 expression in surgically resected specimens may provide prognostic information in addition to conventional pathologic findings for patients with BTC, especially those who have biologically less aggressive phenotypes.

Identification of osteopontin as the most consistently over-expressed gene in intrahepatic cholangiocarcinoma: Detection by oligonucleotide microarray and real-time PCR analysis

AIM: To investigate the molecular pathways involved in human cholangiocarcinogenesis by gene expression profiling.

METHODS: Oligonucleotide arrays (Affymetrix U133A) were used to establish a specific gene expression profile of intrahepatic CCC in comparison to corresponding non-malignant liver tissue. To validate the expression values of the most overexpressed genes, RT-PCR experiments were performed.

RESULTS: Five hundred and fifty-two statistically differentially expressed genes/ESTs (221 probes significantly up-regulated, 331 probes down-regulated; P < 0.05; fold change > 2; ≥ 70%) were identified. Using these data and two-dimensional cluster analysis, a specific gene expression profile was obtained allowing fast and reproducible differentiation of CCC, which was confirmed by supervised neuronal network modelling. The most consistently overexpressed gene (median fold change 33.5, significantly overexpressed in 100%) encoded osteopontin. Furthermore, an association of various genes with the histopathological grading could be demonstrated.

CONCLUSION: A highly specific gene expression profile for intrahepatic CCC was identified, allowing for its fast and reproducible discrimination against non-malignant liver tissue and other liver masses. The most overexpressed gene in intrahepatic CCC was the gene encoding osteopontin. These data may lead to a better understanding of human cholangiocarcinogenesis.

MUC4 is a novel prognostic factor of extrahepatic bile duct carcinoma

PURPOSE

Many of the patients with extrahepatic bile duct carcinoma (EHBDC) show a poor outcome. We have reported that MUC4 is a novel prognostic factor of pancreatic adenocarcinoma and intrahepatic cholangiocarcinoma. The aim of this study is to evaluate the prognostic significance of MUC4 expression in EHBDC.

EXPERIMENTAL DESIGN

We examined the expression profile of MUC4 in EHBDC tissues from 70 patients using immunohistochemistry. MUC4 is a membrane mucin like MUC1. In addition, MUC4 is an intramembrane ligand for receptor tyrosine kinase ErbB2 and is related with regulation of p27. We compared the MUC4 expression with MUC1, ErbB2, or p27 expression in EHBDC.

RESULTS

MUC4 was expressed in 36 of the 70 patients with EHBDC. There was no significant correlation between the MUC4 expression and MUC1, ErbB2, or p27 expression. The survival of 19 patients with high MUC4 expression (>or=20% of carcinoma cells stained) was significantly worse than that of the 51 patients with low MUC4 expression (under 20% of carcinoma cells stained; P = 0.0072). The univariate analysis showed that high MUC4 expression (P = 0.0072), high MUC1 expression (P = 0.0092), histologic grading (P = 0.0029), surgical margin involvement (P = 0.0137), and nodal metastasis (P = 0.0036) were statistically significant risk factors. The backward stepwise multivariate analysis showed that high MUC4 expression (P = 0.0195) and surgical margin involvement (P = 0.0358) were statistically significant independent risk factors.

CONCLUSIONS

MUC4 expression in EHBDC is a new independent factor for poor prognosis and predicts the outcome of patients with EHBDC.

Correlation of p53 gene mutation and expression of P53 protein in cholangiocarcinoma

AIM: To characterize the tumor suppressor gene p53 mutations and study the correlation of p53 gene mutation and the expression of P53 protein in cholangiocarcinoma.

METHODS: A total of 36 unselected, frozen samples of cholangiocarcinoma were collected. p53 gene status(exon 5-8) and P53 protein were examined by automated sequencing and immunohistochemical staining, combined with the clinical parameters of patients.

RESULTS: p53 gene mutations were found in 22 of 36 (61.1%) patients. Nineteen of 36 (52.8%) patients were positive for P53 protein expression. There were significant differences in extent of differentiation and invasion between the positive and negative expression of P53 protein. However, there were no significant differences in pathologic parameters between the mutations and non-mutations.

CONCLUSION: The alterations of the p53 gene evaluated by DNA sequence analysis is relatively accurate. Expression of P53 protein could not act as an independent index to estimate the prognosis of cholangiocarcinoma.

Differential cell cycle-regulatory protein expression in biliary tract adenocarcinoma: correlation with anatomic site, pathologic variables, and clinical outcome

PURPOSE

Biliary tract adenocarcinomas (BTAs), although anatomically related, arise through ill-defined and possibly different location-related pathogenetic pathways. This clinicopathologic study characterizes differences in cell cycle-regulatory protein expression across the spectrum of BTA.

METHODS

Tissue microarrays were prepared from paraffin-embedded surgical specimens with triplicate cores of BTA and benign tissue. Immunohistochemical expression of p53, cyclin D1, p21, Bcl2, p27, Mdm2, and Ki-67 was assessed, and the results were correlated with pathologic variables and survival. Hierarchical clustering was used to partition the data based on protein expression, and then the data were analyzed according to anatomic location.

RESULTS

Tissue from 128 surgical patients (1992 to 2002) was obtained. Tumor sites of origin were intrahepatic cholangiocarcinoma (IH; n = 23), hilar cholangiocarcinoma (Hilar; n = 54), gallbladder (GB; n = 32), and distal bile duct (Distal; n = 19). p27 expression decreased progressively from proximal to distal in the biliary tree and correlated with location-related differences in outcome; cyclin D1 and Bcl2 overexpression also varied according to anatomic site. Aberrant p53 staining and cyclin D1 overexpression were lower in papillary tumors compared with the more common sclerosing tumors. The expression profiles of GB and Hilar were more similar to each other than either was to IH or Distal (86% clustering in the first partition). After an R0 resection, overexpression of Mdm2 (P = .0062) and absent p27 expression (P = .0165) independently predicted poor outcome.

CONCLUSION

BTAs differentially express cell cycle-regulatory proteins based on tumor location and morphology. Prognostic roles were identified for Mdm2 and p27. Overlap in the pathogenesis of GB and Hilar tumors was suggested.

Frequent p16ink4a inactivation is an early and frequent event of intraductal papillary neoplasm of the liver arising in hepatolithiasis

Intraductal papillary neoplasm of the liver (IPNL) is a precursor lesion of intrahepatic cholangiocarcinoma (ICC) arising in hepatolithiasis. In this study, 98 foci of IPNL identified in 39 surgically resected hepatolithiatic livers were investigated for expression of p16INK4a, cyclin D1, p21WAF1/CIP1, p53, mouse double-minute 2 (MDM2), and pRb. In addition, methylation-specific polymerase chain reaction (MSP) for p16 INK4a promoter region was performed in these foci. Nonneoplastic bile ducts from 11 hepatolithiatic livers, 5 histologically normal livers, and 9 cases of nonpapillary conventional ICC were used as controls. Decreased expression of p16INK4A was seen in IPNL group 1 with mild dysplasia and continued along the progression of IPNL to ICC. The expression of cyclin D1, p21WAF1/CIP1,and pRb gradually increased along the progression of IPNL to ICC and became significantly high in IPNL of group 3 (carcinoma in situ). The expression of p53 and MDM2 was increased in IPNL group 3 and group 4 with evident invasive carcinoma. MSP revealed that 54.6% of 44 IPNL foci harbored p16INK4a promoter hypermethylation, and such foci were significantly correlated with decreased expression of p16INK4a protein. Ki-67 labeling index exhibited a stepwise increase from IPNL group 1 to group 4. We conclude that p16INK4a inactivation, due mainly to its promoter hypermethylation, is a frequent and early event of IPNL and may be responsible for genetic and epigenetic alterations of other cell cycle regulators in IPNL.

Cholangiocarcinoma: molecular targeting strategies for chemoprevention and therapy

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

Immunohistochemical analysis of biliary tract lesions

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

Increased cyclin D1 expression in cancer of the ampulla of Vater: relevance to nuclear beta catenin accumulation and k-ras gene mutation

AIMS

Several studies have reported that dysregulation of beta catenin or k-ras mutation promotes cyclin D1 expression. This study investigated the relation between cyclin D1 expression and clinicopathological parameters in carcinoma of the ampulla of Vater (CAV), and also assessed the relation between increased cyclin D1 expression and beta catenin/k-ras status in this series.

METHODS

Thirty CAVs were evaluated for cyclin D1 expression by immunohistochemistry in relation to patient clinicopathological features. Aberrant beta catenin expression and k-ras mutation were also investigated by immunostaining and direct sequencing, and related to cyclin D1 expression.

RESULTS

Increased cyclin D1 expression was seen in 17 of 30 CAVs and was significantly correlated with tumour cell proliferation and disease free survival time (p = 0.018, p = 0.018, respectively). Nuclear accumulation of beta catenin was found in nine of 30 cases, including four cases with missense mutations in exon 3 of CTNNB-1, and was significantly correlated with increased cyclin D1 expression (p = 0.003). k-ras gene mutation was detected in 12 of 30 cases, and was also significantly correlated with increased cyclin D1 expression (p = 0.026). Overall, 14 of 17 CAVs with increased cyclin D1 expression showed nuclear accumulation of beta catenin and/or k-ras mutation.

CONCLUSIONS

Increased cyclin D1 expression appears to be associated with tumour proliferation and poorer clinical outcome in CAV. It is also associated with both aberrant beta catenin expression and k-ras mutation. These results are consistent with the in vitro data that cyclin D1 can be transactivated by activated beta catenin-T cell factor/LEF and k-ras pathways.

Cyclooxygenase-2 promotes human cholangiocarcinoma growth: evidence for cyclooxygenase-2-independent mechanism in celecoxib-mediated induction of p21waf1/cip1 and p27kip1 and cell cycle arrest

The expression of cyclooxygenase-2 (COX-2) is increased in human cholangiocarcinoma. However, the biologic function and molecular mechanisms of COX-2 in the control of cholangiocarcinoma cell growth have not been well established. This study was designed to examine the direct effect of COX-2 and its inhibitor celecoxib on the growth of human intrahepatic cholangiocarcinoma cells. Overexpression of COX-2 or treatment with prostaglandin E(2) (PGE(2)) enhanced human cholangiocarcinoma cell growth, whereas antisense depletion of COX-2 in these cells decreased PGE(2) production and inhibited growth. These findings demonstrate a direct role of COX-2-mediated PGE(2) in the growth regulation of human cholangiocarcinoma cells. Furthermore, the COX-2 inhibitor celecoxib induced a dose-dependent inhibition of cell growth, cell cycle arrest at the G(1)-S checkpoint, and induction of cyclin-dependent kinase inhibitors p21(waf1/cip1) and p27(kip1). However, the high concentration of celecoxib (50 micro M) required for inhibition of growth, the incomplete protection of celecoxib-induced inhibition of cell growth by PGE(2) or COX-2 overexpression, and the fact that overexpression or antisense depletion of COX-2 failed to alter the level of p21(waf1/cip1) and p27(kip1) indicate the existence of a COX-2-independent mechanism in celecoxib-induced inhibition of cholangiocarcinoma cell growth.

MUC4 is a novel prognostic factor of intrahepatic cholangiocarcinoma-mass forming type

Complete surgical resection of the tumor is the sole approach to improve the cure rate of patients with intrahepatic cholangiocarcinoma-mass forming type (ICC-MF). Although patients are treated by curative resection, many of them show poor outcome. Mucin (MUC)4 expression has been implicated as a marker for diagnosis and progression of pancreatic adenocarcinomas, but there is no study of the relationship between MUC4 expression and patient's prognosis in ICC-MF. In the present study, we examined the expression profile of MUC4 in ICC-MF tissue from 27 patients using immunohistochemistry. MUC4 was expressed in the carcinoma tissues of 10 (37%) of the 27 ICC-MF tumors, whereas it was not expressed in normal liver tissue. Because MUC4 is an intramembrane ligand for receptor tyrosine kinase ErbB2 and is related with regulation of p27, we also compared the MUC4 expression with ErbB2 and p27 expressions in ICC-MFs. The patients with MUC4 and ErbB2 double positive expression showed a short survival period compared to non-expressing patients. MUC4 and p27 showed no relationship. The univariate analysis showed that tumor size, intrahepatic metastasis, lymph node metastasis, MUC4 expression, and MUC1 expression were statistically significant risk factors affecting the outcome of the patients with ICC-MF. The multivariate analysis demonstrated that MUC4 expression, as well as surgical margin, were statistically significant independent risk factors. In conclusion, the results suggest that expression of MUC4 in ICC-MF is a new independent factor for poor prognosis and is a useful marker to predict the outcome of the patients with ICC-MF.

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

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