Biliary Tract Carcinogenesis Research Articles

Cholangiocyte derived carcinomas and local microbiota

Trillions of bacteria are present in the gastrointestinal tract as part of the local microbiota. Bacteria have been associated with a wide range of gastrointestinal diseases including malignant neoplasms. The association of bacteria in gastrointestinal and biliary tract carcinogenesis is supported in the paradigm of Helicobacter pylori and intestinal-type gastric cancer. However, the association of bacterial species to a specific carcinoma, different from intestinal-type gastric cancer is unresolved. The relationship of bacteria to a specific malignant neoplasm can drive clinical interventions. We review the classic bacteria risk factors identified using cultures and PCR (polymerase chain reaction) with new research regarding a microbiota approach through 16S rRNA (16S ribosomal ribonucleic acid gene) or metagenomic analysis for selected carcinomas in the biliary tract.

Biliary Tract Carcinogenesis Model Based on Bile Metaproteomics.

Purpose: To analyze human and bacteria proteomic profiles in bile, exposed to a tumor vs. non-tumor microenvironment, in order to identify differences between these conditions, which may contribute to a better understanding of pancreatic carcinogenesis.Patients and Methods: Using liquid chromatography and mass spectrometry, human and bacterial proteomic profiles of a total of 20 bile samples (7 from gallstone (GS) patients, and 13 from pancreatic head ductal adenocarcinoma (PDAC) patients) that were collected during surgery and taken directly from the gallbladder, were compared. g:Profiler and KEGG (Kyoto Encyclopedia of Genes and Genomes) Mapper Reconstruct Pathway were used as the main comparative platform focusing on over-represented biological pathways among human proteins and interaction pathways among bacterial proteins.Results: Three bacterial infection pathways were over-represented in the human PDAC group of proteins. IL-8 is the only human protein that coincides in the three pathways and this protein is only present in the PDAC group. Quantitative and qualitative differences in bacterial proteins suggest a dysbiotic microenvironment in the PDAC group, supported by significant participation of antibiotic biosynthesis enzymes. Prokaryotes interaction signaling pathways highlight the presence of zeatin in the GS group and surfactin in the PDAC group, the former in the metabolism of terpenoids and polyketides, and the latter in both metabolisms of terpenoids, polyketides and quorum sensing. Based on our findings, we propose a bacterial-induced carcinogenesis model for the biliary tract.Conclusion: To the best of our knowledge this is the first study with the aim of comparing human and bacterial bile proteins in a tumor vs. non-tumor microenvironment. We proposed a new carcinogenesis model for the biliary tract based on bile metaproteomic findings. Our results suggest that bacteria may be key players in biliary tract carcinogenesis, in a long-lasting dysbiotic and epithelially harmful microenvironment, in which specific bacterial species' biofilm formation is of utmost importance. Our finding should be further explored in future using in vitro and in vivo investigations.

Biliary carcinogenesis in pancreaticobiliary maljunction.

Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. Because of the excessive length of the common channel in PBM, sphincter action does not directly affect the pancreaticobiliary junction, which allows pancreatic juice to reflux into the biliary tract. According to the results of a nationwide survey, bile duct and gallbladder cancers were found in 6.9 and 13.4% of adult patients with congenital biliary dilatation, respectively, and in 3.1 and 37.4% of those with PBM without biliary dilatation, respectively. Biliary tract cancers develop about 15-20years earlier in patients with PBM than in individuals without PBM; they sometimes develop as double cancers. Carcinogenesis is strongly associated with stasis of bile intermingled with refluxed pancreatic juice. Epithelial cells in the biliary tract of PBM patients are under constant attack from activated pancreatic enzymes, increased secondary bile acids, or other mutagens. This can result in hyperplastic change with increased cell proliferation activity, and in turn, oncogene and/or tumor suppressor gene mutations in the epithelia, leading to the biliary tract carcinogenesis. The carcinogenesis of biliary tract cancer accompanying PBM is considered to involve a hyperplasia-dysplasia-carcinoma sequence induced by chronic inflammation caused by the reflux of pancreatic juice into the biliary tract, which differs from the adenoma-carcinoma sequence or the de novo carcinogenesis associated with biliary tract cancers in the population without PBM. Patients with a relatively long common channel have a similar, albeit slightly lower, risk for gallbladder cancer compared with PBM patients.

Epstein-Barr Virus Infection and Opisthorchiasis: A Story of Cholangiocarcinoma in the Highly Endemic Area

Dear Editor, Cholangiocarcinoma is an important hepatobiliary cancer. It is considered a deadly cancer. This cancer is very common in Indochina area and there are several deaths due to this cancer every year. This cancer is usually late detected. The patients usually present with severe obstructive jaundice. The advanced cancer is usually seen at first diagnosis and it is usually a non resectable mass. Hence, only palliative care is usually provided to the patients with cholangiocarcinoma. The main endemic countries of cholangiocarcinoma are Laos People’s Democratic Republic and Thailand (1). Hundreds of new cases of cholangiocarcinoma are registered in the endemic area (1). The prevention of the cholangiocarcinoma becomes the regional public health policy. It is accepted that chronic opisthorchiasis is the main risk factor of cholangiocarcinoma in this region (1). Of interest, opisthorchiasis is a fluke infestation. The infestation is usually a result of intake of contaminated fresh water fish that is not well cooked. Of interest, raw fish dish is a common local dish in the endemic area, Indochina. In the endemic area, there is a campaign to promote cancer prevention by avoidance of raw fish intake (2). However, there are many additional factors that can promote the cholangiocarcinogenesis including exposure to nitrosamine contamination in local food (3, 4) and exposure to contaminated pesticide in local food (3, 4). An important possible risk is the concurrent infection. Indeed, there are many tropical infections in the endemic area and some might be considered as risk for promoting cholangiocarcinogenesis. For example, concurrent hepatitis B infection is proved to be a risk (5, 6). It is noted that there is a very high rate of hepatitis B seropositive among patients with cholangiocarcinoma (5, 6). Indeed, the concurrent viral infection should be specially focused on since many viruses are proved to have the cytopathogenic effect. In fact, the virus infection is proved for induction of carcinogenesis in many cancers such as uterine cervix cancer, nasopharyngeal cancer and hepatocellular cancer. Hence, it is no doubt that the virus infection might have possible role in carcinogenesis of cholangiocarcinoma. Of several viruses, the Epstein-Barr virus should be mentioned. In oncology, Epstein-Barr virus infection is proved for relationship to carcinogenesis of nasopharyngeal cancer. Focusing on cholangiocarcinoma, there are many reports indicating that Epstein-Barr virus infection might cause cellular aberration and this can superimpose the pathology due to chronic opisthorchiasis resulting in increased chance of cholangiocarcinoma development (7). It should be hereby noted that Epstein-Barr virus infection does not directly induce the carcinogenesis of biliary tract but its cytopathogenic effect superimpose the problem (7, 8). Focusing on Epstein-Barr virus infection, the seroprevalence of this infection is also extremely high in the Indochinese endemic area of opisthorchiasis and cholangiocarcinoma (9). However, there has never been a study on the possible interrelationship between Epstein-Barr virus infection, opisthorchiasis and cholangiocarcinoma in the Indochinese endemic area. Since the Epstein-Barr virus infection is also a disease that relating to poor hygiene (10), the promotion of hygienic behavior and avoidance of oral contact to others to prevent the concurrent Epstein-Barr virus infection should also be suggested to the local people in in the Indochinese endemic area of cholangiocarcinoma.

Bile acid accelerates erbB2-induced pro-tumorigenic activities in biliary tract cancer.

Although very few studies have addressed the molecular and cellular mechanisms underlying the development of biliary tract cancer (BTC), several lines of evidence suggest a role for the erbB receptor family. Overexpression and activation of erbB2 has been reported in a significant percentage of human BTC. Further, we previously reported that overexpression of erbB2 basal epithelial cells of the biliary tract (BK5.erbB2 mouse) led to the development of BTC. However, the mechanisms by which erbB2 overexpression led to the spontaneous development of tumors specifically in the biliary tract are not completely understood. The goals of the current study were to (1) determine whether a cooperative relationship between bile acid exposure and erbB2 activation exists during biliary tract carcinogenesis and (2) to characterize the mechanism(s) underlying bile acid-mediated biliary tract carcinogenesis in cells with activated erbB2. In this study, we demonstrated that the secondary conjugated bile acid, taurochenodeoxycholic acid (TCDC), increased proliferation of primary cultured gallbladder epithelial cells from BK5.erbB2 mice and human BTC cells. TCDC treatment activated EGFR/erbB2 and downstream signaling molecules in both primary cultured cells and human BTC cells. TCDC also increased the expression of epidermal growth factor receptor (EGFR) ligands and TACE activity in human BTC cells. Inhibition of src activation led to attenuation of bile-induced upregulation of TACE activity as well as signaling through the EGFR/erbB2, suggesting that during the development of BTC erbB2 overexpression/activation accelerates the bile acid-induced signaling cascade: bile acid → src → TACE → EGFR/erbB2 → downstream signaling. We also provide direct evidence that bile acids possess tumor promoting capacity in epithelial cells overexpressing erbB2 using the two-stage skin carcinogenesis model. Collectively these findings suggest cooperative roles for bile acid and erbB2 activation in epithelial cell proliferation; bile acid appears to accelerate erbB2-induced pro-tumorigenic activities in the biliary tract and skin.

Mo1134 Expression of Cyclooxygenase-2 in Primary Sclerosing Cholangitis: Implications for Biliary Tract Carcinogenesis

Background: Several characteristics, including hyperlipidemia, obesity, life style, gender, and age, are reported risk factors for gallstones. We investigated characteristics of persons with gallstones detected by mass screening of a healthy population in order to identify lifestyle changes likely to decrease risk. Patients and Methods: We performed health evaluation including abdominal ultrasonography at our institution in 23 848 people (15 346 men and 8502 women) in 2009, detecting gallstones in 1062 (698 men and 364 women). We compared persons with and without gallstones with respect to age, gender, body mass index (BMI), diabetes, liver function, serum lipids, other laboratory parameters, life-style (smoking, exercise, drinking, and sleep), and ultrasonographic findings. Statistical analyses included t tests and odds ratio determinations. Results are given as mean ± SD. Differences with probability (p) values below .05 were considered significant. Results: The gallstone detection rate in this healthy population was 4.5% (4.6% in men and 4.3% in women). The mean age of those with stones was 54 ± 9.7 years, significantly higher than that of others (48 ± 9.8). The mean BMI of subjects with stones was 24.0 ± 3.5, tending to be higher than that of others (23.5 ± 3.1). Serum triglycerides were significantly higher in persons with stones, (121.3 ± 91.4 mg/dL) than that in others (114 ± 96.0). No significant differences were evident between the two groups in liver function, serum amylase, LDL-cholesterol, uric acid, BUN, or HbA1c. No significant differences were found for exercise, smoking, or sleep, but prevalence of gallstones among people who did not drink was significantly lower than in either those who drank moderate quantities ethanol (less than 54 g/day) and drank more. Ultrasonographic findings as adenomyomatosis and gallbladder wall thickening were seen more frequently in subjects with stones. Conclusions: Lowering excessive blood lipids (particularly triglycerides) and lessening obesity as well as refraining from alcohol consumption may be effective in decreasing risk of gallstones.

Prognostic significance of aquaporins in human biliary tract carcinoma

Aquaporins (AQPs) are important in controlling bile formation, however, the exact role of AQPs in human biliary tract carcinogenesis has not been clearly defined. In this study, we analyzed AQP-1, -4, -5 and -8 expression immunohistochemically using tissue microarrays (TMAs) in 81 samples. (45 gallbladder carcinomas and 36 bile duct carcinomas). The survival of patients with high AQP-5 expression was longer compared to that of patients with low AQP-5 expression (P=0.017). Cox's proportional hazard model revealed that AQP-5 expression was an independent prognostic factor (RR, 0.38; P=0.025). Chi-square analysis revealed that high AQP-5 expression correlated to small tumor size in biliary tract carcinoma patients (P=0.006). With regard to the expression of other AQPs, depth of tumor invasion, histological type and serum carbohydrate antigen 19-9 (CA19-9) were associated with high AQP-1 expression (P=0.039, 0.011 and 0.032). However, AQP-4 and AQP-8 expression had no association with clinicopathological factors. Among the 10 patients who underwent gemcitabine (GEM) plus S-1 postoperative chemotherapy, the group of patients (n=5) with high AQP-5 expression were associated with higher rates of both overall and disease-free survival (log-rank P=0.033, 0.002). In conclusion, the results of this study suggest that AQP-5 expression may be associated with prognosis and drug sensitivity in biliary tract carcinoma.

Preneoplastic conditions underlying bile duct cancer.

Malignancies arising from the biliary tract can arise from the epithelial lining of the biliary tract and surrounding tissues. Conditions that predispose to malignancy as well as preneoplastic changes in biliary tract epithelia have been identified. In this overview, we discuss preneoplastic conditions of the biliary tract and emphasize their clinical relevance. Chronic biliary tract inflammation predisposes to cancer in the biliary tract. Biliary tract carcinogenesis involves a multistep process as a consequence of chronic biliary epithelial injury or inflammation. Reminiscent of other gastrointestinal epithelial malignancies such as gastric, colon, and pancreatic cancer, biliary tract cancers may evolve via multistep progression from epithelial hyperplasia and dysplasia to malignant transformation. The potential role of initiating cells is also becoming recognized. In spite of improved risk factor recognition, and advances in diagnostic tools, the early diagnosis of pre-malignant or malignant biliary tract conditions is extremely challenging, and there is a paucity of evidence on which to base their management. As a result, the role of pre-emptive surgery remains largely undefined.

Loss of RUNX3 expression by histone deacetylation is associated with biliary tract carcinogenesis

RUNX3 is a candidate tumor suppressor gene localized in 1p36, a region frequently inactivated through hypermethylation, histone modulation, and other processes in various human tumors. In this study, to elucidate a causal link between RUNX3 expression and biliary tract cancer, we investigated 17 human biliary cancer specimens. In addition, to examine roles of RUNX3 in biliary tract cancer, we restored silenced RUNX3 in the human biliary cancer cell line Mz-ChA-2 using a histone deacetylase inhibitor. Thirteen of 17 human cancer specimens exhibited suppressed RUNX3 expression compared with normal biliary ducts. Moreover, the decreased RUNX3 expression was related to a lower accumulation of acetylated histone H3 associated with RUNX3. In in vitro experiments, vorinostat, a member of a new class of highly potent histone deacetylase inhibitors, restored RUNX3 expression in Mz-ChA-2 cells. Furthermore, vorinostat-induced RUNX3 significantly enhanced p21 expression and growth inhibition of Mz-ChA-2 cells through restoration of TGF-β signaling. These data suggest the significance of histone deacetylation-associated suppression of RUNX3 expression in biliary tract carcinogenesis. Furthermore, vorinostat might hold promise for treating biliary tract cancer through enhancement of TGF-β signaling by restoration of RUNX3.

Lysophosphatidylcholine suppresses apoptotic cell death by inducing cyclooxygenase-2 expression via a Raf-1 dependent mechanism in human cholangiocytes

The high incidence of biliary tract carcinoma in patients with anomalous pancreaticobiliary ductal junction (APBDJ) implicates that a compositional alteration in bile may contribute to the genesis of this cancer. Lysophosphatidylcholine (LPC) is generated in the bile of these patients. Given the role of cyclooxygenase-2 (COX-2) in biliary tract carcinogenesis, we postulated that LPC induces COX-2 in cholangiocytes. The effect of LPC on COX-2 expression in cholangiocytes was evaluated by immunoblot analysis, real-time PCR and reporter gene assay. Apoptosis was induced by TRAIL treatment, and quantified using DAPI staining. Lysophosphatidylcholine increased COX-2 protein expression in cholangiocytes in a concentration- and time-dependent manner. LPC-induced Raf-1 activation was responsible for this COX-2 induction. Accordingly, LPC increased COX-2 mRNA levels in a Raf-1 dependent manner by stabilizing COX-2 mRNA. Finally, LPC attenuated TRAIL-mediated apoptosis through a COX-2/PgE2 dependent mechanism. Collectively, these results implicate that LPC inhibits cholangiocyte apoptosis by inducing COX-2 expression via a Raf-1 dependent mechanism. This anti-apoptotic signaling may participate in biliary tract carcinogenesis in APBDJ patients, and therefore, its interruption may be a viable chemopreventative strategy.

Preferable operative age of choledochal dilation types to prevent patients with pancreaticobiliary maljunction from developing biliary tract carcinogenesis

Pancreaticobiliary maljunction (PBM), which frequently accompanies choledochal dilation, is a high risk factor for biliary tract (gallbladder, bile duct) carcinoma because of the continuous reflux of pancreatic juice into the biliary tract. The aim of this study was to clarify the preferable operative age in PBM patients for the prevention of biliary tract carcinogenesis, with reference to the dilation types of bile ducts. There were 165 PBM patients in total studied, including 92 pediatric patients (< or =15 y) (cystic, 63; spindle-like, 29; nondilation, 0) and 73 adult patients (>15 y) (cystic, 45; spindle-like, 18; nondilation, 10) who underwent operative excision of extrahepatic bile ducts or cholecystectomy. We investigated incidence by age of biliary tract malignancies and the risk according to types of dilation. In the pediatric group, no carcinoma case could be found preoperatively or postoperatively (mean follow-up period, 11.7 y). In the adult group, bile duct carcinomas could be detected in 6 cases of a cystic type (6 of 45; 13.3%) (3 preoperative, 3 postoperative). Among the bile duct carcinoma cases, the youngest patient was a 21-year-old woman who had undergone excision of an extrahepatic bile duct 3 years previously. Gallbladder carcinomas were detected in 16 patients: 3 of 45 cystic (6.7%), 6 of 18 spindle-like (33.3%), and 8 of 10 nondilation (80.0%), in whom the youngest patient was a 41-year-old woman with a spindle-like type. To prevent biliary tract carcinogenesis in PBM patients, cystic-dilated choledochus should be excised in childhood before the development to a precancerous stage. In spindle-like and nondilation types, cholecystectomy is absolutely necessary in early adulthood before age 40.

Inducible nitric oxide synthase upregulates cyclooxygenase-2 in mouse cholangiocytes promoting cell growth.

Both inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) have been implicated in the biliary tract carcinogenesis. However, it is not known whether these inflammatory mediators are induced by interdependent or parallel pathways. Because iNOS activity has been associated with diverse gene expression, the aim of this study was to determine whether iNOS induces COX-2. To address this objective, immortalized, but nonmalignant, murine cholangiocytes, 603B cells were employed for these studies. Both iNOS and COX-2 protein and mRNA were expressed in these cells. However, iNOS inhibition with either N-[3-(aminomethyl) benzyl]acetamidine or stable transfection with an iNOS antisense construct inhibited COX-2 mRNA and protein expression, an effect that was reversed by NO donors. COX-2 mRNA expression in 603B cells was reduced by pharmacological inhibitors of the p38 MAPK and JNK1/2 pathways. In contrast, neither inhibitors of the soluble guanylyl cyclase inhibitor/protein kinase G nor p42/44 MAPK pathways attenuated COX-2 mRNA expression. Finally, 603B cells grew at a rate threefold greater than 603B-iNOS antisense cells. The low growth rate of 603B-iNOS antisense cells could be restored to near that of the parent cell line with exogenous PGE(2.) In conclusion, iNOS induces COX-2 expression in cholangiocytes, which promotes cell growth. COX-2 induction may contribute to iNOS-associated carcinogenesis.

Oxysterols induce cyclooxygenase-2 expression in cholangiocytes: implications for biliary tract carcinogenesis.

Cyclooxygenase-2 (COX-2), which is expressed by cholangiocytes in biliary tract disorders, has recently been implicated in biliary tract carcinogenesis. The mechanisms responsible for this COX-2 expression remain unclear. In human diseases, bile contains oxygenated derivatives of cholesterol (oxysterols) which possess diverse biological properties. Therefore, we determined if oxysterols modulate COX-2 expression. The effect of an oxysterol (22(R)-hydroxycholesterol, 22-HC) on COX-2 expression in KMBC cells, a human cholangiocarcinoma cell line, was examined. 22-HC enhanced COX-2 protein expression. This oxysterol activated p42/44 and p38 MAPK, but not JNK 1/2. A p42/44 MAPK inhibitor did not block COX-2 induction, while p38 MAPK inhibitor effectively attenuated COX-2 induction. Although COX-2 mRNA levels were increased by 22-HC, this increase was not transcriptionally regulated, as 22-OH did not increase activity in a COX-2 promoter gene assay. In contrast, COX-2 mRNA stability was augmented by 22-HC treatment, and this effect was reversed by a p38 MAPK inhibitor. In conclusion, the results demonstrate that the oxysterol 22-HC stabilizes COX-2 mRNA via a p38 MAPK-dependent mechanism. This enhanced COX-2 protein expression by oxysterols may participate in the genesis and progression of cholangiocarcinoma.

Bile acids induce cyclooxygenase-2 expression via the epidermal growth factor receptor in a human cholangiocarcinoma cell line

Although bile acids have been implicated in colon cancer development, their role in biliary tract carcinogenesis remains unexplored. Because receptor tyrosine kinases and cyclooxygenase (COX)-2 have been implicated in carcinogenesis, we examined the hypothesis that bile acids modulate these enzymes in KMBC cells, a human cholangiocarcinoma cell line. The effect of bile acids on epidermal growth factor receptor (EGFR) stimulation, mitogen-activated protein kinase (MAPK) activation, and COX-2 expression was evaluated. Bile acids both induced EGFR phosphorylation and enhanced COX-2 protein expression. Bile acid-induced EGFR phosphorylation was associated with subsequent activation of MAPK p42/44, p38, and c-Jun-N-terminal kinase (JNK). The MAPK inhibitors, PD098059 for MAP or extracellular signal-regulated kinase 1, SB203580 for p38, and BAY 37-9751 for Raf-1, blocked COX-2 induction by bile acids. However, inhibition of JNK activity did not block bile acid-mediated COX-2 induction. The results show that EGFR is activated by bile acids and functions to induce COX-2 expression by an MAPK cascade. This induction of COX-2 may participate in the genesis and progression of cholangiocarcinomas.

Prophylactic Excision of the Gallbladder and Bile Duct for Patients With Pancreaticobiliary Maljunction—Invited Critique

Hypothesis: Pancreaticobiliary maljunction (PBM) is a high-risk factor for biliary tract carcinogenesis because of a continuous reflux of pancreatic juice into the biliary tract. It remains to be disclosed whether we should perform prophylactic excision of gallbladders and bile ducts. Design: A person-year method. Setting: A university hospital. Patients: We studied 68 patients with PBM treated between August 1, 1974, and December 31, 1999. Main Outcome Measures: Relative risks (observed number-expected number ratios) of gallbladder and bile duct carcinomas according to type of bile duct dilation (ie, cystic dilation, diffuse dilation, and nondilation). Results: Observed number-expected number ratios of gallbladder carcinomas were high: 291.3 in 43 patients with cystic dilation, 167.2 in 16 patients with diffuse dilation, and 419.6 in 7 patients with nondilation. Observed number-expected number ratios of bile duct carcinomas were 194.2 in 43 patients with cystic dilation before surgery and 142.8 in 39 patients with cystic dilation after long postsurgical follow-up. All these values were statistically significant (P<.01). Conclusions: The gallbladder carries a high risk for carcinogenesis in all types of dilation in patients with PBM. The bile duct carcinomas of PBM were exclusively identified by the type of cystic dilation. Prophylactic cholecystectomy should be recommended for all dilation types, and prophylactic excision of bile ducts including cholecystectomy should be performed in patients with PBM and cystic dilation. Complete excision of extrahepatic dilated bile ducts and careful follow-up for carcinogenesis in residual dilated bile ducts should be recommended for patients with PBM and cystic dilation.

Prophylactic Excision of the Gallbladder and Bile Duct for Patients With Pancreaticobiliary Maljunction

Pancreaticobiliary maljunction (PBM) is a high-risk factor for biliary tract carcinogenesis because of a continuous reflux of pancreatic juice into the biliary tract. It remains to be disclosed whether we should perform prophylactic excision of gallbladders and bile ducts. A person-year method. A university hospital. We studied 68 patients with PBM treated between August 1, 1974, and December 31, 1999. Relative risks (observed number-expected number ratios) of gallbladder and bile duct carcinomas according to type of bile duct dilation (ie, cystic dilation, diffuse dilation, and nondilation). Observed number-expected number ratios of gallbladder carcinomas were high: 291.3 in 43 patients with cystic dilation, 167.2 in 16 patients with diffuse dilation, and 419.6 in 7 patients with nondilation. Observed number-expected number ratios of bile duct carcinomas were 194.2 in 43 patients with cystic dilation before surgery and 142.8 in 39 patients with cystic dilation after long postsurgical follow-up. All these values were statistically significant (P<.01). The gallbladder carries a high risk for carcinogenesis in all types of dilation in patients with PBM. The bile duct carcinomas of PBM were exclusively identified by the type of cystic dilation. Prophylactic cholecystectomy should be recommended for all dilation types, and prophylactic excision of bile ducts including cholecystectomy should be performed in patients with PBM and cystic dilation. Complete excision of extrahepatic dilated bile ducts and careful follow-up for carcinogenesis in residual dilated bile ducts should be recommended for patients with PBM and cystic dilation.

Precancerous conditions of biliary tract cancer in patients with pancreaticobiliary maljunction: reappraisal of nationwide survey in Japan.

It is widely known that pancreaticobiliary maljunction (PBM), an anomalous arrangement of the pancreaticobiliary ductal system, is frequently associated with biliary tract cancer in patients with or without bile duct dilatation. In 1985, we surveyed patients with PBM who had been operated on at 133 Japanese institutions. A close relationship was shown between biliary tract carcinogenesis and PBM, according to the type of maljunction and age distribution: PBM patients with cystic dilatation had a high risk of bile duct cancer, even in those who were young (aged less than 20 years); the incidence of gallbladder cancer increased markedly in PBM patients over 40 years old with cystic dilatation, while it gradually increased with age in the PBM patients without cystic dilatation. Therefore, we recommend surgical treatment for patients with PBM even if they have no symptoms.

Cellular activity in the gallbladder of children with anomalous arrangement of the pancreaticobiliary duct

Background/Purpose: Anomalous arrangement of the pancreaticobiliary duct (AAPBD) is closely related to congenital biliary dilatation and frequently associated with biliary tract malignancy. To examine the mechanism of biliary tract carcinogenesis in patients with AAPBD, we investigated histologically the early changes in cell proliferative kinetics of the gallbladder mucosa of children with AAPBD. Methods: Twenty-three specimens of gallbladder were obtained from 23 children with AAPBD, and six control specimens were obtained from pediatric patients. All specimens were fixed routinely and paraffin embedded and examined histologically with H&E staining and immunohistochemically with monoclonal antibody Ki-67(MIB-1), which reacts with a human nuclear antigen associated with cell proliferation. Ki-67 labeling index (Ki-67 LI) was obtained by counting the numbers of Ki-67-positive cells per 1,000 gallbladder epithelial cells. Results: Significant differences in Ki-67 LI were noted between children with and without AAPBD. Furthermore, Ki-67 LI and the incidence of epithelial hyperplasia of gallbladder were significantly higher in children with AAPBD in whom the major pancreatic duct joined the common bile duct (P-C type) than in those in whom the common bile duct joined the major pancreatic duct (C-P type). Conclusions: Cellular proliferative activity was increased in children with AAPBD, especially those with the P-C-type anomaly. These results suggest that the early mucosal changes of the gallbladder occurred in early childhood of patients with AAPBD and might be associated with gallbladder cancer. Early diagnosis and early surgical division of the biliary tract and pancreatic duct is recommended for children with AAPBD.

An analysis of mutagens in the contents of the biliary tract in pancreaticobiliary maljunction.

A reflux of pancreatic juice into the biliary tract due to pancreaticobiliary malfunction has been considered to be an important factor in the development of biliary tract carcinogenesis. It is known that the contents of the biliary tract contain not only activated pancreatic enzymes but also certain mutagens. The purpose of this study was thus to isolate and identify such mutagenic substances. A 1:1 mixture of the control bile and pancreatic juice was mixed with bovine enterokinase (10 mg/ml), and the mixture was incubated at 37 degrees C for 12 h. The mixture was demonstrated to be reproducibly mutagenic by the Ames test. The mutagenic substances in these mixtures, which were separated using organic analysis, were found to be included in the water-soluble fraction and to contain amino acids. Mutagenic substances are thought to have a molecular weight of 1,500-3,500 and to be a complex of low-molecular-weight, stable, mutagenic substances including amino acids and peptides.

The effects on cellular functions of bile acid and trypsin in stagnant bile juice in anomalous arrangement of the pancreaticobiliary duct

To examine the reasons for the high frequency of biliary tract carcinogenesis in individuals with anomalous arrangement of the pancreaticobiliary duct (AAPBD), we investigated the effects on cellular functions of bile acid and trypsin, which are possible risk factors for carcinogenesis found in stagnant bile juice, using a chick embryo fibroblast culture system. Bile acid was found to increase PGE 2 synthesis which has been shown to be increased in premalignant lesions, but to suppress the incorporation of [ 3H]-labelled TdR into DNA. On the other hand, trypsin increased the incorporation of [ 3H]TdR into DNA, but did not increase PGE 2 synthesis. These results suggest that both the bile acid and trypsin present in the stagnant bile juice in AAPBD act to stimulate cell proliferation, but that their mechanisms of action on cell growth differ. Therefore, the combination of these effects of different types of tumor promoters in the stagnant bile juice in AAPBD may account for the high incidence of carcinogenesis.