Characteristics of printing company workers newly diagnosed with occupational cholangiocarcinoma

Systematic review of the human health hazards of propylene dichloride

Propylene dichloride (PDC) is a chlorinated substance used primarily as an intermediate in basic organic chemical manufacturing. The United States Environmental Protection Agency (EPA) is currently evaluating PDC as a high-priority substance under the Toxic Substances Control Act (TSCA). We conducted a systematic review of the non-cancer and cancer hazards of PDC using the EPA TSCA and Integrated Risk Information System (IRIS) frameworks. We identified 12 epidemiological, 16 toxicokinetic, 34 experimental animal, and 49 mechanistic studies. Point-of-contact respiratory effects are the most sensitive non-cancer effects after inhalation exposure, and PDC is neither a reproductive nor a developmental toxicant. PDC is not mutagenic in vivo, and while in vitro evidence is mixed, DNA strand breaks consistently occur. Nasal tumors in rats and lung tumors in mice occurred after lifetime high-level inhalation exposure. Cholangiocarcinoma (CCA) was observed in Japanese print workers exposed to high concentrations of PDC. However, co-exposures, as well as liver parasites, hepatitis, and other risk factors, may also have contributed. The cancer mode of action (MOA) analysis revealed that PDC may act through multiple biological pathways occurring sequentially and/or simultaneously, although chronic tissue damage and inflammation likely dominate. Critically, health benchmarks protective of non-cancer effects are expected to protect against cancer in humans.

Mode of action assessment for propylene dichloride as a human carcinogen

As part of a systematic review of the non-cancer and cancer hazards of propylene dichloride (PDC), with a focus on potential carcinogenicity in workers following inhalation exposures, we determined that a mode of action (MOA)-centric framing of cancer effects was warranted. In our MOA analysis, we systematically reviewed the available mechanistic evidence for PDC-induced carcinogenesis, and we mapped biologically plausible MOA pathways and key events (KEs), as guided by the International Programme on Chemical Safety (IPCS)-MOA framework. For the identified pathways and KEs, biological concordance, essentiality of KEs, concordance of empirical observations among KEs, consistency, and analogy were evaluated. The results of this analysis indicate that multiple biologically plausible pathways may contribute to the cancer MOA for PDC, but that the relevant pathways vary by exposure route and level, tissue type, and species; further, more than one pathway may occur concurrently at high exposure levels. While several important data gaps exist, evidence from in vitro mechanistic studies, in vivo experimental animal studies, and ex vivo human tumor tissue analyses indicates that the predominant MOA pathway likely involves saturation of cytochrome p450 2E1 (CYP2E1)-glutathione (GSH) detoxification (molecular initiating event; MIE), accumulation of CYP2E1-oxidative metabolites, cytotoxicity, chronic tissue damage and inflammation, and ultimately tumor formation. Tumors may occur through several subsets of inflammatory KEs, including inflammation-induced aberrant expression of activation-induced cytidine deaminase (AID), which causes DNA strand breaks and mutations and can lead to tumors with a characteristic mutational signature found in occupational cholangiocarcinoma. Dose concordance analysis showed that low-dose mutagenicity (from any pathway) is not a driving MOA, and that prevention of target tissue damage and inflammation (associated with saturation of CYP2E1-GSH detoxification) is expected to also prevent the cascade of processes responsible for tumor formation.

Development of intraductal papillary neoplasm of the bile duct in patients with occupational cholangiocarcinoma

This study aimed to investigate the clinicopathological findings of intraductal papillary neoplasm of the bile duct (IPNB) in patients with occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane to elucidate the development of IPNB to cholangiocarcinoma. The clinicopathological findings of 17 IPNB lesions according to the size (1.5-20 mm in diameter) and their comparison between type 1 (n = 9) and type 2 IPNBs (n = 8) were investigated. An IPNB of <5 mm in size was classified as micro IPNB (n = 7), while those ≥5 mm in size were classified as ordinary IPNB (n = 10). Both types 1 and 2 IPNBs were observed in micro IPNB, and their proportions were not different between micro and ordinary IPNBs. The clinicopathological characteristics of types 1 and 2 IPNBs were fundamentally similar to those previously reported. IPNB with invasive carcinoma was only found in ordinary IPNB although the proportions of low-grade and high-grade epithelium were not different between micro IPNB and ordinary IPNB. All IPNB exhibited γH2AX and S100P, indicating the occurrence of DNA injury and malignant transformation in micro and ordinary IPNBs. These results indicate that the carcinogens may induce micro IPNB with types 1 or 2 at the initiation and then develop ordinary IPNB with types 1 or 2, subsequently, progressing to IPNB with invasive carcinoma in patients with occupational cholangiocarcinoma.

Development of extrahepatic bile ducts and mechanisms of tumorigenesis: Lessons from mouse models

The biliary system is a highly branched tubular network consisting of intrahepatic bile ducts (IHBDs) and extrahepatic bile ducts (EHBDs). IHBDs are derived from hepatic progenitor cells, while EHBDs originate directly from the endoderm through a separate branching morphogenetic process. Traits that are important for cancer are often found to overlap in developmental and other processes. Therefore, it has been suggested that intrahepatic cholangiocarcinomas (iCCAs) and extrahepatic cholangiocarcinomas (eCCAs) have different developmental mechanisms. While much evidence is being gathered on the mechanism of iCCAs, the evidence for eCCA is still very limited. The main reason for this is that there are very few appropriate animal models for eCCA. We can gain important insights from these animal models, particularly genetically engineered mouse models (GEMMs). GEMMs are immunocompetent and mimic human CCA subtypes with a specific mutational pattern, allowing the development of precancerous lesions, that is, biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB). This review provides a summary of the pathogenesis and mechanisms of eCCA that can be revealed by GEMMs. Furthermore, we discuss several clinical questions, such as whether BilIN and IPNB really become malignant, whether the peribiliary gland is the origin of eCCAs, and others.

Pitfalls and promises of bile duct alternatives: A narrative review

Biliodigestive anastomosis between the extrahepatic bile duct and the intestine for bile duct disease is a gastrointestinal reconstruction that abolishes duodenal papilla function and frequently causes retrograde cholangitis. This chronic inflammation can cause liver dysfunction, liver abscess, and even bile duct cancer. Although research has been conducted for over 100 years to directly repair bile duct defects with alternatives, no bile duct substitute (BDS) has been developed. This narrative review confirms our understanding of why bile duct alternatives have not been developed and explains the clinical applicability of BDSs in the near future. We searched the PubMed electronic database to identify studies conducted to develop BDSs until December 2021 and identified studies in English. Two independent reviewers reviewed studies on large animals with 8 or more cases. Four types of BDSs prevail: Autologous tissue, non-bioabsorbable material, bioabsorbable material, and others (decellularized tissue, 3D-printed structures, etc.). In most studies, BDSs failed due to obstruction of the lumen or stenosis of the anastomosis with the native bile duct. BDS has not been developed primarily because control of bile duct wound healing and regeneration has not been elucidated. A BDS expected to be clinically applied in the near future incorporates a bioabsorbable material that allows for regeneration of the bile duct outside the BDS.

Emerging treatment evolutions and integrated molecular characteristics of biliary tract cancers

Biliary tract cancers (BTCs) consist of a group of highly heterogeneous malignancies that are characterized by genomic differences among tumors from different anatomic sites. The current treatment for BTC includes surgery, chemotherapy, target therapy, and immunotherapy. Although surgery remains the primary option for localized disease, representing the only potential curative treatment, a high risk of recurrence cannot be neglected. Chemotherapy has been considered the standard of care for both advanced and metastatic disease and in adjuvant settings. However, drug resistance is a major obstacle associated with chemotherapy. The development of genetic testing technologies, including next-generation sequencing, has opened the door for the identification of drug targets and candidate molecules. A series of preclinical studies has demonstrated the role of gene mutations, abnormal signaling pathways, and immunosuppression in the pathogenesis of BTC, laying the foundation for the application of targeted therapy and immunotherapy. A variety of molecularly targeted agents, including pemigatinib, have shown promising survival benefits in patients with advanced disease. The rapidly evolving role of multimodal therapy represents the subject of this review.

Inhibition of FGF10-ERK signal activation suppresses intraductal papillary neoplasm of the bile duct and its associated carcinomas

Evidence regarding intraductal papillary neoplasm of the bile duct (IPNB) as a type of precancerous lesion of cholangiocarcinoma is limited. Moreover, a reproducible in vivo model is lacking, and IPNB pathogenesis remains unclear. Here, we use a doxycycline-inducible tetracycline (Tet)-on mice model to control fibroblast growth factor 10 (FGF10) expression, which regulates branching and tubule formation. FGF10-induced IPNB mimics the multifocal and divergent human IPNB phenotypes via the FGF10-FGF receptor 2 (FGFR2)-RAS-extracellular-signal-regulated kinase (ERK) signaling pathway. A paracrine/autocrine growth factor is sufficient to initiate and maintain IPNB originating from the peribiliary glands, including biliary stem/progenitor cells. With Kras^G12D, p53, or p16 mutations or both, Fgf10-induced IPNB shows stepwise carcinogenesis, causing associated invasive carcinoma. Fgf10-induced papillary changes and progression are suppressed by the inhibition of the FGF10-FGFR2-RAS-ERK signaling pathway, demonstrating that the signal is a therapeutic target for IPNB and associated carcinoma.

Multifocal origin of occupational cholangiocarcinoma revealed by comparison of multilesion mutational profiles

Recently identified occupational cholangiocarcinoma among printing workers is characterized by chronic bile duct injuries and precancerous or early cancerous lesions at multiple sites of the bile ducts. These observations suggested the potential multifocal carcinogenesis of the disease. We performed whole-exome analysis of multiple lesions, including the invasive carcinomas and precancerous lesions of four occupational cholangiocarcinoma cases. A much higher mutation burden was observed in both the invasive carcinomas (mean 76.3/Mb) and precancerous lesions (mean 71.8/Mb) than in non-occupational cholangiocarcinomas (mean 1.6/Mb). Most somatic mutations identified in 11 of 16 lesions did not overlap with each other. In contrast, a unique trinucleotide mutational signature of GpCpY to GpTpY was shared among the lesions. These results suggest that most of these lesions are multiclonal in origin and that common mutagenic processes, which may be induced by exposure to haloalkanes or their metabolites, generated somatic mutations at different sites of the bile ducts. A similarly high mutation rate had already been identified in the precancerous lesions, implying an increased potential for carcinogenesis throughout the biliary tree. These genomic features support the importance of ongoing close follow-up of the patients as a group at high risk of recurrence.

Immunosuppressive tumor microenvironment in occupational cholangiocarcinoma: Supportive evidence for the efficacy of immune checkpoint inhibitor therapy

BACKGROUND

Occupational cholangiocarcinoma (CCA) was first described in patients who were working at a printing company in Osaka, Japan. Recently, the therapeutic efficacy and safety of a PD1 inhibitor nivolumab are being evaluated in patients with occupational CCA in an investigator-initiated clinical trial. The therapeutic effects of immune checkpoint inhibitors are closely associated with immune cells.

METHODS

Immunohistochemical analysis was performed to characterize immune cells in the tumor microenvironment of occupational CCA. The status of mismatch repair (MMR)/microsatellite instability (MSI) was also examined.

RESULTS

The tumor stroma of occupational CCA was characterized by abundant infiltration of immune cells expressing CD3, CD4, CD8, CD163, FOXP3, and granzyme B. Additionally, lymphocytes expressing immune checkpoint receptors, such as PD1, CTLA4, LAG3, TIM3, and TIGIT, were frequently infiltrated. The loss of immunohistochemical expression of the MMR proteins (MLH1, MSH2, PMS2, and MSH6) was not observed in cases of occupational CCA, and MSI was not detected.

CONCLUSIONS

The tumor microenvironment of occupational CCA had features of immunosuppression, and the occurrence of T-cell dysfunction or exhaustion was suggested. The results provide supportive evidence for the efficacy of immune checkpoint inhibitor therapy for this disease.

Risk factors and characteristics of young patients with the biliary tract carcinoma: results of a project study for biliary surgery by the Japanese Society of Hepato-Biliary-Pancreatic Surgery

PURPOSE

This study aimed to elucidate the characteristics of biliary tract carcinoma (BTC) in young patients.

METHODS

This is a nationwide multicenter, retrospective cohort study supervised by the Japanese Society of Hepato-Biliary-Pancreatic Surgery (JSHBPS). Clinicopathological data of patients aged <50 years diagnosed with BTC from January 1997 to December 2011 were collected from 211 training institutes for highly advanced surgery registered by the JHBPS.

RESULTS

Data of 774 young patients aged <50 years were obtained from 102 institutes. Pancreaticobiliary maljunction (PBM) (10.6%) was most frequently associated with young BTC. However, organic solvents caused by printing or other occupations were only 2.5%. PBM was further associated with early onset of BTC and was noted in 38.9% of patients aged <30 years. Subgroup analysis revealed that the distributions of PBM, choledochal cysts, cholelithiasis, hepatitis B virus, and past history of cancer were significantly varied depending on the site of BTC. These results suggested that each site of BTC has a different mechanism for cancer development.

CONCLUSION

Although the most frequent factor for young BTC patients was PBM, cancer-associated factors were dramatically different in each BTC site. These results might be useful to elucidate the etiology of young BTC patients.

Multiple cholangiocarcinomas in the intrahepatic and extrahepatic biliary tree due to dichloromethane exposure: a case report

Background

An outbreak of cholangiocarcinoma in Japan has led to widespread concern among workers in printing plants. In March 2013, the Japanese Ministry of Health, Labour and Welfare, confirmed a causal relationship between cholangiocarcinoma and long-term exposure to dichloromethane (DCM) and 1,2-dichloropropane (DCP), which were widely used in printing plants. We herein report a rare case of successful radical resection of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts caused by past exposure to DCM.

Case presentation

A 54-year-old man developed brown urine 22 years after his last exposure to DCP and DCM. He had an 11-year history of working at a printing plant from the age of 21 to 31 years and dealt with organic solvents during his employment. Enhanced computed tomography revealed a thickened distal bile duct wall with upstream biliary dilatation and multiple intrahepatic cholangiocarcinomas located in liver segments III, VI, and VIII. Biopsy of the distal bile duct wall revealed adenocarcinoma, and a diagnosis of distal cholangiocarcinoma was made. Tumor marker levels were within the reference range (carcinoembryonic antigen, 3.3 ng/mL; carbohydrate antigen 19-9, 25.4 U/mL; SPAN-1, 13 U/mL; and DUPAN-2, 33 U/mL). The multiple intrahepatic and extrahepatic bile duct cancers were treated by subtotal stomach-preserving pancreatoduodenectomy and partial hepatectomy of segments III, VI, and VIII. Pathological examination of the surgical specimens revealed multiple cholangiocarcinomas with well-differentiated adenocarcinoma in the biliary tree. The patient was still alive without recurrence 17 months after the operation.

Conclusions

We experienced a rare case of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts that developed 22 years after the patient’s last exposure to DCP and DCM. Long-term and careful follow-up is required for workers with an occupational history of exposure to organic solvents because of the risk of development of cholangiocarcinoma.

Occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to 1,2-dichloropropane and dichloromethane at a printing company: a case report

Background

Cholangiocarcinoma due to exposure to 1.2-dichloropropane (DCP) or dichloromethane (DCM) is classified as occupational cholangiocarcinoma. We report a case of occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to organic solvents at a printing company.

Case presentation

A 41-year-old man presented to our hospital with jaundice and anorexia. He had previously worked for 6 years at a printing company where an outbreak of occupational cholangiocarcinoma occurred and was exposed to high concentrations of organic solvents during his employment. Computed tomography demonstrated lower bile duct obstruction by the bulky nodal metastasis at the hepatoduodenal ligament with upstream biliary dilatation, an intraductal papillary tumor in the dilated left superior lateral bile duct (B2), and enlargement of the periaortic nodes. Clinical diagnosis of an unresectable invasive intraductal papillary neoplasm of the bile duct (IPNB) with extensive nodal metastasis was made. Although chemotherapy and laparoscopic gastrojejunostomy were performed for the duodenal obstruction, the patient died due to rupture of the tumor. Pathological examination of the autopsy specimen revealed well-differentiated adenocarcinoma at the stromal site along Glisson’s sheath in segment 3, an IPNB lesion without invasion in B2, and biliary intraepithelial neoplasia and chronic bile duct injury at various sites in the large bile ducts. The bulky lymph node (poorly differentiated adenocarcinoma with partial squamous cell differentiation) invaded the bile duct and duodenum.

Conclusions

We report a case of occupational cholangiocarcinoma that developed 18 years after the end of exposure to DCP and DCM. Long-term follow-up is required to carefully survey development of cholangiocarcinoma in workers with an occupational history of exposure to organic solvents.

The Clinical Significance of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Patients with Occupational Cholangiocarcinoma

Objective

The present study aimed to identify the clinical significance of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in patients with occupational cholangiocarcinoma.

Methods

This study included 10 men with occupational cholangiocarcinoma who were former or current workers at a printing company in Osaka, Japan. Of the 10 patients, 2 had 2 main tumors and 1 had 3 main tumors. Twelve FDG-PET imaging findings in the 10 patients could be analyzed. We evaluated the relationships between FDG-PET imaging parameters and clinicopathological findings of occupational cholangiocarcinoma.

Results

Abnormal FDG uptake was observed in 8 of the 14 main tumors, with maximum standardized uptake values ranging from 2.9 to 11.0, and the sensitivity was 57.1%. Four patients had lymph node metastases, and abnormal marrow uptake was detected in all these patients. Although precancerous lesions, such as biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB) without any invasion, were not detected, abnormal FDG uptake was demonstrated in 2 of 4 patients with IPNB having an associated invasive carcinoma.

Conclusions

Although FDG-PET may be useful for assessing tumor progression factors, such as lymph node metastasis, it cannot accurately detect precancerous lesions, such as BilIN and IPNB without invasive carcinoma.

Occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane

A cluster of cholangiocarcinoma among printing company workers who were exposed to 1,2-dichloropropane and/or dichloromethane was classified by the Ministry of Health, Labour and Welfare of Japan on 1 October 2013 as "occupational cholangiocarcinoma". At the time of the diagnosis of cholangiocarcinoma, levels of γ-glutamyl transferase, and aspartate and alanine aminotransferases were elevated, and had been elevated in some patients several years prior to the diagnosis. Regional dilatation of intrahepatic bile ducts without tumor-induced obstruction was characteristic in diagnostic imaging. Pathological examination found chronic bile duct injury with DNA damage, precancerous/preinvasive lesions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct in various sites of the large bile ducts, and invasive cholangiocarcinoma such as mass-forming type and intraductal growth-type intrahepatic cholangiocarcinoma and mainly papillary-type extrahepatic cholangiocarcinoma. Whole-exome analysis of the cancerous tissues showed hypermutation, substantial strand bias, and unique trinucleotide mutational changes. Patients seemed to suffer high incidence of postoperative complications including intra-abdominal, which might be related to chronic bile duct injury. Postoperative recurrence from multicentric origins occurred in some patients, as DNA-injured bile ducts have high carcinogenic potential. Aggressive treatment, including second resections for such multicentric recurrences, appeared to be effective. In 2014, the International Agency for Research on Cancer classified 1,2-dichloropropane as Group 1 (carcinogenic to humans) and dichloromethane as Group 2A (probably carcinogenic to humans) carcinogens.

Low Incidence of Lymph Node Metastasis After Resection of Hepatitis Virus-Related Intrahepatic Cholangiocarcinoma

BACKGROUND AND OBJECTIVES

We determined the rates of initial lymph node metastasis following curative resection of mass-forming type-intrahepatic cholangiocarcinoma (ICC) in patients with and without hepatitis virus infection.

METHODS

We enrolled 87 patients between January 2000 and December 2013 with ICC without preoperative lymph node metastasis and without lymph node dissection. Patients included 32 who were seropositive for hepatitis B or C virus (virus group) and 55 who had no evidence of hepatitis virus infection (nonvirus group). Postsurgical outcomes and initial recurrence of the groups were compared, and we identified the risk factors for lymph node metastasis as initial recurrence.

RESULTS

Platelet counts and prothrombin activities were significantly lower in the virus group compared with those of the nonvirus group. The number of patients with chronic hepatitis or liver cirrhosis was significantly higher in the virus group compared with the nonvirus group as well as their respective rates of recurrence-free survival. One patient (3%) in the virus group and 14 patients (25%) in the nonvirus group had lymph node metastasis as initial recurrence (p = 0.007). Multivariate analysis revealed that the absence of hepatitis virus infection as an independent risk factor (p = 0.047).

CONCLUSION

Hepatitis virus-associated mass-forming-type ICC confers a low risk of lymph node metastasis as initial postoperative recurrence.

Spontaneous Production of Glutathione-Conjugated Forms of 1,2-Dichloropropane: Comparative Study on Metabolic Activation Processes of Dihaloalkanes Associated with Occupational Cholangiocarcinoma

Recently, epidemiological studies revealed a positive relationship between an outbreak of occupational cholangiocarcinoma and exposure to organic solvents containing 1,2-dichloropropane (1,2-DCP). In 1,2-DCP-administered animal models, we previously found biliary excretion of potentially oncogenic metabolites consisting of glutathione- (GSH-) conjugated forms of 1,2-DCP (GS-DCPs); however, the GS-DCP production pathway remains unknown. To enhance the understanding of 1,2-DCP-related risks to human health, we examined the reactivity of GSH with 1,2-DCP in vitro and compared it to that with dichloromethane (DCM), the other putative substance responsible for occupational cholangiocarcinoma. Our results showed that 1,2-DCP was spontaneously conjugated with GSH, whereas this spontaneous reaction was hardly detected between DCM and GSH. Further analysis revealed that glutathione S-transferase theta 1 (GSTT1) exhibited less effect on the 1,2-DCP reaction as compared with that observed for DCM. Although GSTT1-mediated bioactivation of dihaloalkanes could be a plausible explanation for the production of reactive metabolites related to carcinogenesis based on previous studies, this catalytic pathway might not mainly contribute to 1,2-DCP-related occupational cholangiocarcinoma. Considering the higher catalytic activity of GSTT1 on DCM as compared with that on 1,2-DCP, our findings suggested differences in the activation processes associated with 1,2-DCP and DCM metabolism.

MR imaging and MR cholangiopancreatography of cholangiocarcinoma developing in printing company workers

PURPOSE

To retrospectively investigate magnetic resonance (MR) imaging findings of occupational cholangiocarcinoma (oCC) occurring among workers in printing companies in Japan, compared to those of non-occupational cholangiocarcinoma (nCC), primary sclerosing cholangitis (PSC), and age-matched normal controls (NORs).

MATERIALS AND METHODS

Participants comprised 27 consecutive patients (oCC, n = 5; nCC, n = 8; PSC, n = 6; NOR, n = 8) who underwent MR imaging between May 2009 and October 2012. MR imaging was evaluated with respect to tumor characteristics, abnormal MR cholangiographic findings (PSC-like findings), bile duct stricture, and signal changes of the hepatic parenchyma.

RESULTS

Tumors were detected in all nCCs and four oCCs. Tumors displayed a mass-forming type in all nCCs and two oCCs, and an intraductal growth type in two oCCs. Abnormal cholangiographic findings were detected in all oCCs and PSCs, but not in any nCCs or NORs. All oCCs and seven nCCs showed biliary strictures longer than 1 cm; five PSCs showed biliary strictures shorter than 1 cm. Both intra- and extrahepatic biliary strictures were detected in three PSCs and two oCCs. Peripheral hepatic hyperintensity on T2-weighted imaging was detected in two nCCs, two PSCs, and two oCCs.

CONCLUSION

These results indicated that MR imaging of oCC showed findings of both PSC and nCC.

The PD-1/PD-L1 axis may be aberrantly activated in occupational cholangiocarcinoma

An outbreak of cholangiocarcinoma in a printing company was reported in Japan, and these cases were regarded as an occupational disease (occupational cholangiocarcinoma). This study examined the expression status of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in occupational cholangiocarcinoma. Immunostaining of PD-1, PD-L1, CD3, CD8, and CD163 was performed using tissue sections of occupational cholangiocarcinoma (n = 10), and the results were compared with those of control cases consisting of intrahepatic (n = 23) and extrahepatic (n = 45) cholangiocarcinoma. Carcinoma cells expressed PD-L1 in all cases of occupational cholangiocarcinoma, whereas the detection of PD-L1 expression in cholangiocarcinoma cells was limited to a low number of cases (less than 10%) in the control subjects. In cases of occupational cholangiocarcinoma, occasional PD-L1 expression was also noted in precancerous/preinvasive lesions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. Additionally, tumor-associated macrophages and tumor-infiltrating T cells expressed PD-L1 and PD-1, respectively. The number of PD-L1-positive mononuclear cells, PD-1-positive lymphocytes, and CD8-positive lymphocytes infiltrating within the tumor was significantly higher in occupational cholangiocarcinoma compared with that in control cases. These results indicate that immune escape via the PD-1/PD-L1 axis may be occurring in occupational cholangiocarcinoma.

Three simultaneous cases of hypersensitivity pneumonitis and acute lung injury caused by dichloromethane

Three middle‐aged male patients were admitted to our hospital complaining of dry cough, dyspnoea, and fever. All three of them had cleaned a refrigerator at a Chinese noodle mill using paint remover containing dichloromethane (90%) the previous day. Chest X‐rays revealed bilateral diffuse infiltrative shadows on the lungs. We performed transbronchial lung biopsies and bronchoalveolar lavage (BAL) via bronchoscopy for each patient. Bronchoalveolar lavage showed increased total cell count as well as lymphocyte and neutrophil fraction. Transbronchial lung biopsy revealed Masson bodies and slight lymphocyte infiltration into the alveolar septa. We diagnosed all three patients with hypersensitivity pneumonitis and acute lung injury caused by exposure to the paint remover containing dichloromethane. Two of these patients ultimately went into respiratory failure, requiring the administration of a corticosteroid. The third patient improved without the need of steroid therapy.

Investigation of Spatial Clustering of Biliary Tract Cancer Incidence in Osaka, Japan: Neighborhood Effect of a Printing Factory

BACKGROUND

In 2013, an unusually high incidence of biliary tract cancer among current or former workers of the offset color proof printing department of a printing company in Osaka, Japan, was reported. The purpose of this study was to examine whether distance from the printing factory was associated with incidence of biliary tract cancer and whether incident biliary tract cancer cases clustered around the printing factory in Osaka using population-based cancer registry data.

METHODS

We estimated the age-standardized incidence ratio of biliary tract cancer according to distance from this printing factory. We also searched for clusters of biliary tract cancer incidence using spatial scan statistics.

RESULTS

We did not observe statistically significantly high or low standardized incidence ratios for residents in each area categorized by distance from the printing factory for the entire sample or for either sex. The scan statistics did not show any statistically significant clustering of biliary tract cancer incidence anywhere in Osaka prefecture in 2004-2007.

CONCLUSIONS

There was no statistically significant clustering of biliary tract cancer incidence around the printing factory or in any other areas in Osaka, Japan, between 2004 and 2007. To date, even if some substances have diffused outside this source factory, they do not appear to have influenced the incidence of biliary tract cancer in neighboring residents.

Outcomes after resection of occupational cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane is recognized as occupational cholangiocarcinoma. The aim of this study was to investigate the outcomes after resection of occupational cholangiocarcinoma to establish a treatment strategy for this disease.

METHODS

Clinicopathological findings and outcomes after surgical intervention in 20 patients with occupational cholangiocarcinoma were investigated.

RESULTS

Of 20 the patients, curative resection was performed in 16 patients. Three patients underwent radiation at the stump of the bile ducts. Adjuvant chemotherapy was performed in 12 patients. Biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and/or chronic bile duct injury was detected in most subjects. Intraabdominal infection developed after surgery in nine patients. Cholangiocarcinoma recurred in 12 of the 20 patients. The recurrent tumors in five patients developed at a different part of the bile duct from the primary tumor and a second resection was performed in four of these five patients.

CONCLUSIONS

The incidence of postoperative complications including intraabdominal infection was high in patients with occupational cholangiocarcinoma. Multicentric recurrence occurred not infrequently after surgery because the bile ducts had a high potential for the development of carcinoma. The aggressive treatment including second resection for the multicentric recurrence appeared to be effective.

Comparison of clinicopathological characteristics between patients with occupational and non-occupational intrahepatic cholangiocarcinoma

BACKGROUND

An outbreak of cholangiocarcinoma has been reported among workers of an offset color proof-printing department at a printing company in Japan. In this study, we compared the clinicopathological findings of this type of intrahepatic cholangiocarcinoma (occupational ICC) and non-occupational ICC.

METHODS

The clinical records of 51 patients with perihilar-type ICC who underwent liver resection, including five patients with occupational ICC were retrospectively reviewed. The clinicopathological features were compared.

RESULTS

In the occupational group, the patients were significantly younger (P < 0.01), while serum γ-glutamyl transpeptidase activity and the proportions of patients with regional dilatation of the bile ducts without tumor-induced obstruction were significantly higher (P = 0.041 and P < 0.01, respectively); the indocyanine green retention rate at 15 min was significantly lower (P = 0.020). On pathological examinations, precancerous or early cancerous lesions, such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct, were observed at various sites of the bile ducts in all occupational ICC patients; such lesions were observed in only six patients in the control group (P < 0.01).

CONCLUSIONS

The clinicopathological findings including age, liver function test results, diagnostic imaging findings, and pathological findings differed between the occupational and control groups.

Outcomes of Hepatic Resection in Intrahepatic Cholangiocarcinoma Patients with Diabetes, Hypertension, and Dyslipidemia: Significance of Routine Follow-Up

BACKGROUND

The outcomes of hepatic resection in intrahepatic cholangiocarcinoma (ICC) patients with diabetes mellitus (DM), hypertension (HT), and dyslipidemia (DL) (metabolic components) remain unclear.

METHODS

The outcomes of 43 ICC patients without known risk factors for ICC who underwent hepatic resection were retrospectively reviewed. These patients were divided into three groups: those followed-up for metabolic components at least every 6 months (follow-up group, n=16), those not followed-up for metabolic components (no follow-up group, n=14), and those without metabolic components (control group, n=13).

RESULTS

In the follow-up group, 13 (81%) patients were further examined for ICC during follow-up because of abnormal screening results, such as elevated serum gamma-glutamyl transpeptidase and carbohydrate antigen 19-9 (CA19-9) concentrations or detection of hepatic tumor on ultrasonography and/or computed tomography, whereas most patients in the other two groups exhibited ICC-related symptoms. No patient in the follow-up group exhibited lymph node metastasis, whereas 43% of those in the no follow-up group and 46% in the control group had lymph node metastasis (p=0.005 and 0.004 vs. the follow-up group, respectively). All 16 patients in the follow-up group were diagnosed as International Union Against Cancer pathologic stage I or II (early stage). There were no significant differences in the incidence of postoperative recurrence between the three groups; however, the incidence of extrahepatic recurrence was lower in the follow-up group than in the no follow-up group and the control group (13% vs. 78% vs. 63%, p=0.0232). The 1-, 3-, and 5-year overall survivalrates in the follow-up group were better than those in the no follow-up and control groups (93/93/66% vs. 77/34/34% and 85/24/0%, p=0.034 and 0.001, respectively).

CONCLUSIONS

Routine measurement of serum gamma-glutamyl transpeptidase and/or CA19-9 levels and imaging examinations every 12 months (or 6 months, if possible) are recommended during follow-up for DM, HT, and DL to detect ICC at an early stage.

Pathological spectrum of bile duct lesions from chronic bile duct injury to invasive cholangiocarcinoma corresponding to bile duct imaging findings of occupational cholangiocarcinoma

BACKGROUND

We aimed to identify the pathological characteristics of occupational cholangiocarcinoma.

METHODS

We examined the location and distribution of the carcinomas: atypical epithelium including biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB); and chronic bile duct injuries in operative or autopsy liver specimens from 16 patients. We examined the detailed pathological findings and diagnostic imaging of three patients. Immunohistochemical analysis using primary antibodies against γH2AX and S100P was performed.

RESULTS

BilIN and chronic bile duct injury were observed in 16 patients, and IPNB or invasive IPNB was observed in 11 patients. BilIN, IPNB, and/or chronic bile duct injury were observed in almost all the large bile ducts. Regional dilatation of the bile ducts without tumor-induced obstruction revealed such pathological changes. Highly positive results for the γH2AX and S100P markers were noted in invasive carcinoma, BilIN, and IPNB, whereas positive results for γH2AX and negative results for S100P were noted in non-neoplastic biliary epithelium.

CONCLUSIONS

The carcinogenic process of occupational cholangiocarcinoma comprised chronic bile duct injury and DNA damage in almost all the large bile ducts, along with induction of precancerous lesions and development of invasive carcinoma. Such pathological findings reflected radiological changes on diagnostic imaging.

Screening and surveillance for occupational cholangiocarcinoma in workers exposed to organic solvents

PURPOSE

This study aimed to establish an efficient strategy for screening and surveillance for occupational cholangiocarcinoma.

METHODS

We evaluated the consecutive changes in laboratory findings during regular health examinations and in abdominal ultrasonography findings before the diagnosis of occupational cholangiocarcinoma in nine patients. The results of laboratory tests and abdominal ultrasonography at the time of diagnosis were also examined.

RESULTS

In all patients, the serum γ-glutamyl transpeptidase (γ-GTP) activity increased several years before the diagnosis of cholangiocarcinoma. The serum alanine aminotransferase (ALT) activity also increased several years before the diagnosis, following an increase in the serum aspartate aminotransferase (AST) activity in most patients. Abdominal ultrasonography before the diagnosis revealed regional dilatation of the bile ducts, which continued to enlarge. At the time of diagnosis, the γ-GTP, AST, and ALT activities were increased in nine, seven, and seven patients, respectively. The regional dilatation of bile ducts without tumor-induced stenosis, dilated bile ducts due to tumor-induced stenosis, space-occupying lesions, and/or lymph node swelling were observed. The serum concentrations of carbohydrate antigen 19-9 (CA 19-9) and/or carcinoembryonic antigen (CEA) were increased in all patients.

CONCLUSIONS

Regular health examinations with a combination of ultrasonography and laboratory tests including the γ-GTP, AST, ALT, CA 19-9, and CEA levels are useful for screening and surveillance for occupational cholangiocarcinoma.