Aberrant expression of pyloric gland-type mucin in mucin-producing bile duct carcinomas: A clear difference between the core peptide and the carbohydrate moiety

A comprehensive expression analysis of mucins in appendiceal carcinoma in a multicenter study: MUC3 is a novel prognostic factor

BACKGROUND

Mucins are implicated in survival in various cancers, but there have been no report addressed on survival in appendiceal carcinoma, an uncommon disease with different clinical and pathological features from those of other colon cancers. We aimed to investigate the clinical implications of expression of mucins in appendiceal carcinoma.

METHODS

Expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6, MUC16 and MUC17 in cancer tissue were examined by immunohistochemistry in 108 cases of surgically resected appendiceal carcinoma.

RESULTS

The following relationships of mucins with clinicopathologic factors were identified: MUC1 with positive lymphatic invasion (p = 0.036); MUC2 with histological type (mucinous carcinoma, p<0.001), superficial invasion depth (p = 0.007), negative venous invasion (p = 0.003), and curative resection (p = 0.019); MUC3 with non-curative resection (p = 0.017); MUC5AC with histological type (mucinous carcinoma, p = 0.002), negative lymphatic invasion (p = 0.021), and negative venous invasion (p = 0.022); and MUC16 with positive lymph node metastasis (p = 0.035), positive venous invasion (p<0.05), and non-curative resection (p = 0.035). A poor prognosis was related to positive lymph node metastasis (p = 0.04), positive lymphatic invasion (p = 0.02), positive venous invasion (p<0.001), non-curative resection (p<0.001), and positive expression of MUC3 (p = 0.004). In multivariate analysis, positive venous invasion (HR: 6.93, 95% CI: 1.93-24.96, p = 0.003), non-curative resection (HR: 10.19, 95% CI: 3.05-34.07, p<0.001) and positive MUC3 expression (HR: 3.37, 95% CI: 1.13-10.03, p = 0.03) were identified as significant independent prognostic factors in patients with appendiceal carcinoma.

CONCLUSIONS

Expression of MUC3 in appendiceal carcinoma is an independent factor for poor prognosis and a useful predictor of outcome in patients with appendiceal carcinoma after surgery.

Pathobiological implications of mucin (MUC) expression in the outcome of small bowel cancer

Mucins have been associated with survival in various cancer patients, but there have been no studies of mucins in small bowel carcinoma (SBC). In this study, we investigated the relationships between mucin expression and clinicopathologic factors in 60 SBC cases, in which expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6 and MUC16 in cancer and normal tissues were examined by immunohistochemistry. MUC1, MUC5AC and MUC16 expression was increased in SBC lesions compared to the normal epithelium, and expression of these mucins was related to clinicopathologic factors, as follows: MUC1 [tumor location (p = 0.019), depth (p = 0.017) and curability (p = 0.007)], MUC5AC [tumor location (p = 0.063) and lymph node metastasis (p = 0.059)], and MUC16 [venous invasion (p = 0.016) and curability (p = 0.016)]. Analysis of 58 cases with survival data revealed five factors associated with a poor prognosis: poorly-differentiated or neuroendocrine histological type (p<0.001), lymph node metastasis (p<0.001), lymphatic invasion (p = 0.026), venous invasion (p<0.001) and curative resection (p<0.001), in addition to expression of MUC1 (p = 0.042), MUC5AC (p = 0.007) and MUC16 (p<0.001). In subsequent multivariate analysis with curability as the covariate, lymph node metastasis, venous invasion, and MUC5AC and/or MUC16 expression were significantly related to the prognosis. Multivariate analysis in curative cases (n = 45) showed that SBC with MUC5AC and/or MUC16 expression had a significantly independent high hazard risk after adjusting for the effects of venous invasion (hazard ratio: 5.6, 95% confidence interval: 1.8-17). In conclusion, the study shows that a MUC5AC-positive and/or MUC16-positive status is useful as a predictor of a poor outcome in patients with SBC.

Mucins in human neoplasms: clinical pathology, gene expression and diagnostic application

Mucins are high molecular weight glycoproteins that play important roles in carcinogenesis and tumor invasion. Our immunohistochemical studies demonstrated that MUC1 or MUC4 expression is related to the aggressive behavior and poor outcome of human neoplasms. MUC2 is expressed in indolent pancreatobiliary neoplasms, but these tumors sometimes show invasive growth with MUC1 expression in invasive areas. MUC5AC shows de novo high expression in many types of precancerous lesions of pancreatobiliary cancers and is an effective marker for early detection of the neoplasms. The combination of MUC1, MUC2, MUC4 and MUC5AC expression may be useful for early detection and evaluation of the potential for malignancy of pancreatobiliary neoplasms. Regarding the mechanism of mucin expression, we have recently reported that expression of the mucin genes is regulated epigenetically in cancer cell lines, using quantitative MassARRAY analysis, methylation-specific polymerase chain reaction analysis and chromatin immunoprecipitation analysis, with confirmation by the treatment with 5-aza-2'-deoxycytidine and trichostatin A. We have also developed a monoclonal antibody against the MUC1 cytoplasmic tail domain, which has many biological roles. Based on all of the above findings, we suggest that translational research into mucin gene expression mechanisms, including epigenetics, may provide new tools for early and accurate detection of human neoplasms.

A novel approach to biliary tract pathology based on similarities to pancreatic counterparts: is the biliary tract an incomplete pancreas?

There are peribiliary glands around the biliary tract, and these glands drain into the bile duct lumen. Interestingly, small amounts of pancreatic exocrine acini are intermingled with these glands. Experimental studies using animals suggest that the biliary tract shows some potential for pancreatic differentiation. It is noteworth that the biliary tract and pancreas have similar pathological features. IgG4-related sclerosing cholangitis and autoimmune pancreatitis are representative inflammatory diseases with similar features. Intraductal papillary neoplasms are found in the biliary tract and also in the pancreas: intraductal papillary neoplasm of the bile duct (IPNB) and intraductal papillary mucinous neoplasm of the pancreas (IPMN). IPNB and IPMN share common histologic and phenotypic features and biological behaviors. Interestingly, mucinous cystic neoplasm (MCN) arises in both the pancreas and the hepatobiliary system. Intraductal tubular neoplasia is found in both the biliary tract and pancreas as well. Intraepithelial neoplasm is found in the biliary tract and pancreas: biliary intraepithelial neoplasm (BilIN) and pancreatic intraepithelial neoplasm (PanIN). BilIN and PanIN are followed by conventional invasive adenocarcinoma, while IPNB and IPMN are followed by tubular adenocarcinoma and mucinous carcinoma in both organs. Further study of the biliary tract's pathophysiology based on its similarity to pancreatic counterparts is warranted.

Tumorigenesis and phenotypic characteristics of mucin-producing bile duct tumors: an immunohistochemical approach

Intraductal papillary neoplasm of the bile duct (IPNB) is characterized by exophytic proliferation of neoplastic epithelial cells with fibrovascular stalks in bile duct lumen, mucin hypersecretion, and considerable dilatation or multilocular changes of the affected bile ducts. A mucin-producing bile duct tumor is an IPNB with excessive mucin production and clinical symptoms. Herein, the phenotypes as well as the tumorigenesis and progression of IPNB are reviewed with immunohistochemical assistance. The tumors are subdivided into three phenotypes: pancreatobiliary, intestinal, and gastric. About half of IPNB cases are of the pancreatobiliary type, and the remaining half are of the intestinal type. Aberrant expression of CDX2 with MUC2 and CK20 is related to the development of intestinal metaplasia. Inactivation of P16INK4a and nuclear expression of beta-catenin are related to the development of IPNB. Decreased expression of membranous beta-catenin and E-cadherin and aberrant expression of MMP-7 and -9 and of MUC1 are related to invasion of IPNB with tubular adenocarcinoma, whereas MUC2 is involved in the invasion of IPNB with mucinous carcinoma. IPNB can be regarded as a counterpart of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, particularly the main duct type. More comparative studies between IPNB and pancreatic IPMN are recommended for further analysis of these papillary neoplasms.

Mucin gene expression in bile of patients with and without gallstone disease, collected by endoscopic retrograde cholangiography

AIM: To investigate the pattern of mucin expression and concentration in bile obtained during endoscopic retrograde cholangiography (ERC) in relation to gallstone disease.

METHODS: Bile samples obtained at ERC from 29 consecutive patients, 17 with and 12 without gallstone disease were evaluated for mucin content by gel filtration on a Sepharose CL-4B column. Dot blot analysis for bile mucin apoproteins was performed with antibodies to Mucin 1 (MUC1), MUC2, MUC3, MUC5AC, MUC5B and MUC6. Staining intensity score (0-3) was used as a measure of antigen expression.

RESULTS: MUC1, MUC2, MUC3, MUC5AC, MUC5B and MUC6 were demonstrated in 34.4%, 34.4%, 51.7%, 51.7%, 55.1% and 27.5% of bile samples, respectively. The staining intensity scores were 0.62 ± 0.94, 0.58 ± 0.90, 0.79 ± 0.97, 1.06 ± 1.22, 1.20 ± 1.26 and 0.41 ± 0.73, respectively. Mean mucin concentration measured in bile by the Sepharose CL-4B method was 22.8 ± 24.0 mg/mL (range 3.4-89.0 mg/mL). Mean protein concentration was 8.1 ± 4.8 mg/mL (range 1.7-23.2 mg/mL).

CONCLUSION: High levels of MUC3, MUC5AC and MUC5B are expressed in bile aspirated during ERC examination. A specific pattern of mucin gene expression or change in mucin concentration was not found in gallstone disease.

Expression profiles of MUC mucins and trefoil factor family (TFF) peptides in the intrahepatic biliary system: physiological distribution and pathological significance

Mucin secreted by mucosal epithelial cells plays a role in the protection of the mucosal surface and also is involved in pathological processes. So far, MUC1-4, 5AC, 5B, 6-8, 11-13 and 15-17 genes coding the backbone mucin core protein have been identified in humans. Their diverse physiological distribution and pathological alterations have been reported. Trefoil factor family (TFF) peptides are mucin-associated molecules co-expressed with MUC mucins and involved in the maintenance of mucosal barrier and the biological behavior of epithelial and carcinoma cells. Intrahepatic biliary system is a route linking the bile canaliculi and the extrahepatic bile duct for the excretion of bile synthesized by hepatocytes. Biliary epithelial cells line in the intrahepatic biliary system, secreting mucin and other molecules involved in the maintenance and regulation of the system. In this review, the latest information regarding properties, expression profiles and regulation of MUC mucins and TFF peptides in the intrahepatic biliary system is summarized. In particular, we focus on the expression profiles and their significance of MUC mucins in developmental and normal livers, various hepatobiliary diseases and intrahepatic cholangiocarcinoma.