Immunohistochemical study of mucin carbohydrates and core proteins in human pancreatic tumors

Expression of mucin antigens in human cancers and its relationship with malignancy potential

Mucins are high molecular weight glycoproteins having oligosaccharides attached to the apomucin protein backbone by O-glycosidic linkages. Biochemical studies on the structures and the organ specificities of several mucin core proteins (MUC1-MUC7) have been reported during the past several years. In the present study of pancreas and intrahepatic bile duct tumors, MUC1 mucin (membrane bound mucin detected by monoclonal antibody, DF3) was highly expressed in invasive ductal carcinomas of the pancreas (IDC) and invasive cholangiocarcinomas of the liver (ICC), which show invasive growth and a poor prognosis, but it was rarely expressed in intraductal papillary mucinous tumors of the pancreas (IPMT) and bile duct cystadenocarcinomas of the liver (BDCC), which show a favorable prognosis. In contrast, MUC2 mucin (intestinal type secretory mucin detected by polyclonal antibody, anti-MRP) was rarely expressed in IDC and ICC, whereas it was highly expressed in IPMT and BDCC. The results suggest that the differences in the expression of MUC1 and MUC2 mucins are a useful prognostic indicator of malignancy potential in the neoplasms of the pancreas and intrahepatic bile duct. Moreover, the expression of MUC1 and MUC2 mucins was a useful indicator of the malignancy potential of tumors derived from other organs, such as the ampulla of Vater, stomach and breast. In another study on the expression of several MUC1 mucin antigens with different patterns of glycosylation, sialylated-MUC1 mucin detected by monoclonal antibody, MY.1E12, was found to be expressed in all the invasive carcinomas (IDC and ICC) but was not frequently seen in the non-invasive type tumors (IPMT and BDCC), although the other types of MUC1 mucins did not show such contrast between the invasive and non-invasive type tumors. The results suggest that sialylation of MUC1 mucin is associated with invasive growth of neoplasms. In contrast, our study of the expression of MUC2 mRNA (transcript of intestinal type mucin) and MUC5AC mRNA (transcript of gastric type mucin) by in situ hybridization in the tumors of the pancreas and intrahepatic bile duct found that the non-invasive type tumors (IPMT and BDCC) synthesize MUC2 mRNA and MUC5AC mRNA, whereas most of the invasive carcinomas (IDC and ICC) do not. Furthermore, patients positive for MUC2 mRNA or MUC5AC mRNA expression in the tumors showed significantly better survival than the patients with no expression. The production of MUC2 or MUC5AC, an abundant extracellular intestinal or gastric type secretory mucin with high viscosity may be correlated, by a majority of the non-invasive type tumors, with the expansive growth of the tumors that display lower levels of invasion and metastasis.

Mucin antigen expression in gastric carcinomas of young and old adults

The striking differences in the histological features of gastric cancers in young and old adults have been thought to be related to differences in the biological behavior of these cancers. Recently, a new grading system (Goseki's classification) showed that the prognosis of the patient is particularly related to the mucin content of the carcinoma. In this study, we examined differences in mucin antigen expression in cancers from young and old adults and whether antigen expression is related to the clinical outcome. The expression of two mucin core proteins (DF3 antigen [MUC1 gene product] and MRP antigen [MUC2 gene product] and a mucin-type carbohydrate antigen [sialosyl-Tn; STn]) was examined immunohistochemically in gastric cancers from 69 young adults (30 to 39 years of age) and 110 old adults (80 to 89 years of age). The incidence rates of the three histological types (tubular adenocarcinoma, poorly differentiated adenocarcinoma, and signet-ring cell carcinoma) were different in the young and old adults. However, among the mucin antigens examined, only DF3 showed significantly higher frequency of expression in the old adults, and the difference was seen only in tubular adenocarcinomas (young, 43%; old, 68%) and poorly differentiated adenocarcinomas (young, 19%; old, 49%). In these two histological types, there was no difference in the frequency of MRP or STn expression between the young and old adults, although the old adults showed a high incidence of intestinal metaplasia that was positive for both antigens. Signet-ring cell carcinomas showed no significant difference in expression rates of the three antigens in young and old adults, but there were significantly higher expression rates in young patients for both MRP (young, 67%; old, 65%) and STn (young, 71%; old, 57%) and a lower rate of DF3 expression (young, 0%; old, 14%). In both young and old adults, the patients with DF3-positive carcinomas showed significantly poorer survival than those without DF3 expression, whereas there was not significant difference in the survival of the patient groups with positive and negative MRP or STn reactivity. In conclusion, the expression of DF3 was influenced by the age of patients and was related to the outcome. In contrast, MRP and STn expression was related more to the histological pattern of the tumor than to the age of the patient and did not correlate with the outcome.

MUC2 gene expression is found in noninvasive tumors but not in invasive tumors of the pancreas and liver: its close relationship with prognosis of the patients

We have previously reported that MUC2 apomucin was highly expressed in noninvasive tumors of the pancreas (intraductal papillary tumor [IdPT]) and liver (bile duct cystadenocarcinoma [BdCC]), which show more favorable outcomes than invasive carcinomas. In contrast, MUC2 was rarely expressed in invasive carcinomas of the pancreas (invasive ductal carcinoma [IDC]) and the liver (invasive cholangiocarcinoma [ICC]). In the present study, we examined localization of MUC2 messenger RNA (MUC2 mRNA) by using a complementary DNA (cDNA) probe for the MUC2 tandem repeat for in situ hybridization (pHAM1). Localization of MUC2 apomucin was determined by using an antibody directed against MUC2 apomucin (anti-MRP) for immunohistochemistry study. Eleven IdPTs and 10 IDCs of the pancreas, and 8 BdCC and 8 ICCs of the liver were examined. Nine (82%) of 11 IdPTs showed positive expression of MUC2 mRNA in the neoplastic cells, whereas none (0%) of the IDCs showed expression of MUC2 mRNA. Six (75%) of the 8 BdCCs showed positive expression of MUC2 mRNA in the neoplastic cells, whereas none (0%) of the 8 ICCs showed expression of MUC2 mRNA. The localization of MUC2 mRNA and that of MUC2 apomucin usually coincided, although a few cases (1 IDC, 1 BdCC, and 1 ICC) showed focal expression of MUC2 apomucin despite the absence of detectable MUC2 mRNA. These results indicate that the expression of MUC2 apomucin in IdPTs and BdCCs correlates with expression of MUC2 mRNA. In both patient groups with pancreatic tumors and hepatic tumors, patients with positive MUC2 mRNA expression in the tumors showed significantly better survival than those with negative MUC2 mRNA expression in the tumors. The production of MUC2, an abundant extracellular mucin, by most IdPTs and BdCCs may be correlated with tumors that display lower levels of invasion and metastasis.

Expression of MUC apomucins in normal pancreas and pancreatic tumours

The epithelial expression of apomucins MUC1, MUC2, MUC3, and MUC5/6 was examined in normal pancreas and in pancreatic lesions, using immunohistochemical methods. In normal pancreas (n = 5), MUC1 apomucin was expressed in ducts and some acini, but there was no expression of MUC2, MUC3, or MUC5/6. In chronic pancreatitis (n = 5), MUC1 apomucin was expressed, but expression of the other apomucins was not noted. However, mucous hyperplastic foci of pancreatic ducts expressed MUC5/6 apomucin in 2/5 cases (40 percent). In intraductal papillary-mucinous neoplasm (IPMN) of the pancreas (n = 9), MUC1, MUC2, MUC3, and MUC5/6 apomucins were expressed in 8/9 (89 percent), 0/9 (0 per cent), 4/9 (44 per cent), and 9/9 (100 per cent) case, respectively. In pancreatic mucinous cystadenoma (n = 8), MUC1, MUC2, MUC3, and MUC5/6 apomucins were expressed in 7/8 (88 percent), 0/8 (0 percent), (25 percent), and 3/8 (38 percent) cases, respectively. In invasive ductal adenocarcinoma of the pancreas (n = 25), expression of MUC1, MUC2, MUC3, and MUC5/6 apomucins was found in 25/25 (100 percent), 1/25 (4 percent), 20/25 (80 percent), and 24/25 (96 percent) cases, respectively. Atypical mucous duct hyperplasia near cancer cells consistently expressed MUC1 apomucin and occasionally expressed MUC3 and MUC5/6. In positive cases, MUC1 apomucin expression was noted in the cell membrane facing the ductal or neoplastic lumina, while expression of MUC2, MUC3, and MUC5/6 apomucins was found in the cytoplasm. These results suggest that MUC3 and MUC5/6 apomucins newly emerge during the neoplastic transformation of pancreatic mucinous cystadenoma and IPMN and during pancreatic ductal carcinogenesis, while MUC1 apomucin remains positive and MUC2 apomucin remains almost negative during neoplastic transformation.

Detection of Tn, sialosyl-Tn and T antigens in hereditary nonpolyposis colorectal cancer

The simple mucin-type carbohydrate antigens Tn, sialosyl-Tn, T and the 'cryptic' sialylated variant of the last represent the mucin core oligosaccharide structures that are produced in the initial steps of the mucin biosynthetic pathway. Utilizing monoclonal antibodies anti-Tn antigen (HB-Tn1), anti-sialosyl-Tn antigen (HB-STn1), anti-T antigen (HB-T1) and the biotinylated Amaranthus caudatus agglutinin (ACA), we have investigated the expression of the simple mucin-type carbohydrate antigens in hereditary nonpolyposis colorectal cancer (HNPCC; 15 cases) compared with sporadic colorectal cancer (CRC; 60 cases) and normal colonic mucosa (30 cases). A variable positivity of Tn, sialosyl-Tn, T and the cryptic sialylated form of this latter antigen was encountered in both HNPCC and sporadic CRC cases; in addition, in normal colonic mucosa a constant reactivity was encountered only for Tn and the cryptic sialylated form of T, while negative results were always obtained for sialosyl-Tn and T antigens. Statistical analysis, performed using a Chi-square test, showed significantly lower (P = 0.037) expression of sialosyl-Tn and higher (P = 0.022) expression of T in HNPCC than in sporadic CRC, suggesting a greater presence of beta 1,3 galactosyltransferase activity in HNPCC than in sporadic CRC. We were unable to identify a peculiar phenotype for HNPCC with simultaneous evaluation of reactivity for HB-Tn1, HB-STn1, HB-T1 and ACA; the biological significance of the preferential expression of T antigen in HNPCC remains to be investigated.

Expression of MUC apomucins in normal pancreas and pancreatic tumours

The epithelial expression of apomucins MUC1, MUC2, MUC3, and MUC5/6 was examined in normal pancreas and in pancreatic lesions, using immunohistochemical methods. In normal pancreas (n = 5), MUC1 apomucin was expressed in ducts and some acini, but there was no expression of MUC2, MUC3, or MUC5/6. In chronic pancreatitis (n = 5), MUC1 apomucin was expressed, but expression of the other apomucins was not noted. However, mucous hyperplastic foci of pancreatic ducts expressed MUC5/6 apomucin in 2/5 cases (40 percent). In intraductal papillary-mucinous neoplasm (IPMN) of the pancreas (n = 9), MUC1, MUC2, MUC3, and MUC5/6 apomucins were expressed in 8/9 (89 percent), 0/9 (0 per cent), 4/9 (44 per cent), and 9/9 (100 per cent) case, respectively. In pancreatic mucinous cystadenoma (n = 8), MUC1, MUC2, MUC3, and MUC5/6 apomucins were expressed in 7/8 (88 percent), 0/8 (0 percent), (25 percent), and 3/8 (38 percent) cases, respectively. In invasive ductal adenocarcinoma of the pancreas (n = 25), expression of MUC1, MUC2, MUC3, and MUC5/6 apomucins was found in 25/25 (100 percent), 1/25 (4 percent), 20/25 (80 percent), and 24/25 (96 percent) cases, respectively. Atypical mucous duct hyperplasia near cancer cells consistently expressed MUC1 apomucin and occasionally expressed MUC3 and MUC5/6. In positive cases, MUC1 apomucin expression was noted in the cell membrane facing the ductal or neoplastic lumina, while expression of MUC2, MUC3, and MUC5/6 apomucins was found in the cytoplasm. These results suggest that MUC3 and MUC5/6 apomucins newly emerge during the neoplastic transformation of pancreatic mucinous cystadenoma and IPMN and during pancreatic ductal carcinogenesis, while MUC1 apomucin remains positive and MUC2 apomucin remains almost negative during neoplastic transformation.

Mucin glycoproteins in neoplasia

Mucins are high molecular weight glycoproteins that are heavily glycosylated with many oligosaccharide side chains linked O-glycosidically to the protein backbone. With the recent application of molecular biological methods, the structures of apomucins and regulation of mucin genes are beginning to be understood. At least nine human mucin genes have been identified to date. Although a complete protein sequence is known for only three human mucins (MUC1, MUC2, and MUC7), common motifs have been identified in many mucins. The pattern of tissue and cell-specific expression of these mucin genes are emerging, suggesting a distinct role for each member of this diverse mucin gene family. In epithelial cancers, many of the phenotypic markers for pre-malignant and malignant cells have been found on the carbohydrate and peptide moieties of mucin glycoproteins. The expression of carbohydrate antigens appears to be due to modification of peripheral carbohydrate structures and the exposure of inner core region carbohydrates. The expression of some of the sialylated carbohydrate antigens appears to correlate with poor prognosis and increased metastatic potential in some cancers. The exposure of peptide backbone structures of mucin glycoproteins in malignancies appears to be due to abnormal glycosylation during biosynthesis. Dysregulation of tissue and cell-specific expression of mucin genes also occurs in epithelial cancers. At present, the role of mucin glycoproteins in various stages of epithelial cell carcinogenesis (including the preneoplastic state and metastasis), in cancer diagnosis and immunotherapy is under investigation.

Expression of mucin antigens and Lewis X-related antigens in carcinomas and dysplasia of the pharynx and larynx

Recent studies have identified that mucin antigens and Lewis X (Lex)-related antigens behave like oncodevelopmental tumor-associated antigens in several human adenocarcinomas. However, the expression of these antigens in pharyngeal and laryngeal squamous cell carcinomas (SCC) and in the precursor lesion is not fully elucidated yet. In the present study, the expression of mucin core protein antigens associated with the MUC1 gene product (DF3 antigen, mammary-type apomucin) and the MUC2 gene product (intestinal-MRP antigen, intestinal-type apomucin) mucin carbohydrate antigens that are associated with the earliest steps in mucin glycosylation (Tn, sialyl-Tn and T), and Lex-related antigens (Lex, Ley and sialyl Lex-i) in biopsy or resected specimens from 26 normal squamous epithelia (NSE), 49 dysplastic squamous epithelia (DSE) and 51 SCC were examined. The DF3 antigen was not expressed in NSE (0%), whereas it was expressed in 20 DSE (41%) and in 31 SCC (61%). The intestinal-MRP antigen showed no expression in NSE, DSE or SCC. The Tn antigen showed no expression in NSE, but showed low expression rates in DSE (14%) and in SCC (16%). The sialyl-Tn and T antigens were expressed in NSE, as well as in DSE and SCC. The T antigen expression increased with progression from NSE to DSE to SCC, while the sialyl-Tn antigen did not show such a tendency. Any of the three Lex-related antigens showed no characteristic expression in DSE and SCC. In the eight antigens examined, only DF3 antigen was an effective marker for DSE and SCC in the pharyngeal and laryngeal region. Cytoplasmic expression of DF3 and sialyl-Tn antigens were more frequently seen in SCC than in DSE, and might be useful to differentiate SCC from DSE.

Expression of mucin carbohydrates and core proteins in carcinomas of the ampulla of Vater: their relationship to prognosis

We examined the expression of carbohydrate antigens which are associated with the earliest steps in mucin glycosylation (Tn and sialosyl-Tn) and the expression of the mucin core protein antigens associated with MUC1 gene product (DF3 antigen) as well as MUC2 gene product (intestinal-MRP antigen) in tissues from 38 patients with carcinoma of the ampulla of Vater, in order to determine whether these mucin antigens are available as tumor markers or not, and to evaluate whether their expression is correlated with the biological behavior of the carcinomas or not. DF3 antigen showed a relatively high expression rate (61%) in the carcinoma tissues, but was rarely expressed in the non-neoplastic epithelium around the carcinomas in the region of the ampulla of Vater. Tn and sialosyl-Tn antigens showed high expression rates in the carcinoma tissues (86% and 84% each), whereas they showed rare or no expression in the non-neoplastic epithelium around the carcinomas, except for highly restricted expression in the duodenal villous epithelium. The patients with positive DF3 expression in the carcinoma showed significantly poorer survival than those with negative DF3 expression (P < 0.05), whereas the patients with positive intestinal-MRP expression in the carcinoma showed significantly more favorable survival than those with negative intestinal-MRP expression (P < 0.05). The expression rate of DF3 antigen was significantly higher in the cases with deep invasion into the pancreas (89%) than in those with no or minimal invasion (52%) (P < 0.05). In contrast, the expression rate of intestinal-MRP antigen was significantly higher in the cases with no or minimal invasion into the pancreas (38%) than in those with deep invasion (0%) (P<0.05). In conclusion, the expression of DF3, To and sialosyl-Tn antigens is an effective histopathological indicator for carcinomas in the area of the ampulla of Vater, and the expression of DF3 and intestinal-MRP antigens is a useful indicator of the prognosis of the patients.

The role of tumor rejection antigens in host antitumor defense mechanisms

BACKGROUND

Normal cells undergo contact inhibition of growth when their surface molecules interact. Tumor cells, however, have undergone a mutation that prevents this arrest of growth upon contact inhibition and allows constant growth. Thus, growth inhibition fails to occur despite the interaction of surface molecules. In recent years a subgroup of these surface molecules has been of interest to cancer investigators. This subgroup has been termed the tumor rejection antigens (TRAs). As the name implies, these are specific to the tumor of origin and may direct the immune system of the host to target the tumor cells and kill them.

METHODS

A literature search was carried out on TRAs to ascertain the current thinking on the subject.

RESULTS

Initial studies of TRAs have revealed that some of them may be heat shock proteins (HSPs). In particular, grp96, a number of the HSP90 family, has been implicated. More recent studies, however, have shown that HSPs alone may not be immunogenic but may act as carrier proteins for tumor specific peptides.

CONCLUSION

Such findings have led to speculation that HSPs or their associated peptides may have a role in the diagnosis and/or treatment of specific cancers. Immunotherapy and bispecific antibodies in particular are areas in which HSPs may prove to be useful.

Prostaglandin E2 alters terminal glycosylation of high molecular weight glycoproteins, released by pig gastric mucous cells in vitro

The gastric mucus layer consists of high molecular weight glycoproteins (HMG). E-Type prostaglandins (PGs) stimulate total HMG release from isolated gastric mucous cells. We determined the effects of PGE2 on HMG glycosylation. Pig gastric mucous cells were cultured for 20 h with 1 mumol/l PGE2. Released HMG were isolated by gel chromatography and periodic acid-Schiff (PAS)-positive sugars and protein-bound [14C]GlcNAc were determined. Monosaccharides terminally linked to HMG oligosaccharide chains were monitored by lectin enzyme linked immunosorbent assay (ELISA): N-acetylglucosamine (GlcNAc) with Datura stramonium agglutinin, N-acetylgalactosamine (GalNAc) with soy bean agglutinin, fucose (Fuc) with Ulex europaeus I agglutinin and sialic acids (Sial) with Sambucus nigra agglutinin. PGE2 stimulated total HMG release, indicated by an increase of PAS-positive sugars to 170% and [14C]GlcNAc to 220% of controls. Terminal GlcNAc increased to 128%, GalNAc to 133%, Fuc to 165% and Sial to 182%. In addition to stimulation of total HMG release, PGE2 caused alterations of HMG glycosylation, which may modulate HMG viscosity and microbiological barrier function.

Distribution of Tn antigen recognized by an anti-Tn monoclonal antibody (MLS128) in normal and malignant tissues of the digestive tract

Alterations in the normal glycosylation process are often associated with oncogenic transformation. Using an anti-Tn monoclonal antibody, MLS128, we have investigated the immunohistochemical localization of Tn antigen in normal and malignant tissues of the digestive tract. In normal tissues, MLS128 was immunoreactive with the squamous epithelium of the esophagus and was weakly reactive with the columnar epithelia of the stomach, duodenum, colon, bile duct and pancreatic duct. In malignant tissues, positive immunostaining was detected with high frequency (75%-100%) in carcinomas of the esophagus, stomach colon, biliary tract and pancreas, whereas 2 of 11 (18%) hepatocellular carcinomas were positive. Tn antigen was detected in the upper two-thirds of the normal squamous epithelium, and was often detected in squamous cell carcinomas with cancer pearls (keratinization). These results suggest that the expression of Tn antigen is related to the differentiation of squamous epithelium, or to keratinization. In normal columnar epithelial cells. Tn antigen was localized mainly to the Golgi area. This intracellular localization was preserved in well-differentiated papillary adenocarcinomas of the colon, but was lost in most cases of tubular adenocarcinomas.

Mucin antigens expression and Ki-67 labeling in breast cancer: the peculiarity in scirrhous carcinoma

The expression of mucin-related antigens (Tn, T, Sialosyl-Tn [STn], DF3 [mammary-type apomucin related antigen], and intestinal-MRP [intestinal-type apomucin related antigen]) as well as Ki-67 labeling was examined in 58 mammary invasive ductal carcinomas (IDC) divided into 26 scirrhous subtype (SC) and 32 non-scirrhous subtype comprising papillotubular carcinoma and solid-tubular carcinoma (PT-ST). These data were analyzed in connection with the various pathological prognostic factors such as nodal status, tumor size, estrogen receptor status and histological grading of carcinomas. The results were as follows: (a) in SC, the expression rate of Tn was significantly higher in the cases with positive lymph node metastasis or with large tumor size (> 2 cm) than in those with negative lymph node metastasis or with small tumor size (< or = 2 cm); (b) in PT-ST, the expression rate of STn was higher in the cases with positive lymph node metastasis or with large tumor size than in those with negative lymph node metastasis or with small tumor size; (c) in SC, Ki-67 labeling was significantly higher in the cases with positive lymph node metastasis than in those with negative lymph node metastasis; and (d) in PT-ST, Ki-67 labeling was lower in the cases with positive lymph node metastasis than in those with negative lymph node metastasis. In conclusion, Tn antigen expression was correlated with pathological prognostic factors in SC but not in PT-ST, whereas STn antigen expression was correlated with pathological prognostic factors in PT-ST but not in SC.(ABSTRACT TRUNCATED AT 250 WORDS)

Radioimmunoimaging of colon cancer xenografts with anti-Tn monoclonal antibody

Tn antigen is a glycosylated tumor associated antigen and a murine monoclonal antibody, MLS128, has been identified to react with it. The potential of MLS128 for the radioimmunoimaging of colorectal cancer was studied. MLS128 was labeled with radioiodine by the chloramine-T method or indium-111 (111In) by using isothiocyanatobenzyl EDTA, and was injected into nude mice bearing human colon cancer xenografts. Radiolabeled MLS128 showed a high and specific localization in xenografted tumor. At 48 h after injection, the %ID/g of 125I-labeled MLS128 in the tumor was 34.69, whereas that of isotype matched control antibody, FLOPC21, was 5.58 and the tumor-to-nontumor radioactivity ratios of 125I-labeled MLS128 reached to 4.56, 17.84 and 23.62 for the blood, liver and bone, respectively. 111In-labeled MLS128 showed similar results. High accumulation of MLS128 in xenografted tumors suggested that the monoclonal antibody MLS128 is promising for radioimmunoimaging of colorectal cancer.

Expression of mucin core protein of mammary type in primary liver cancer

Expression of mucin core protein of mammary type (MUC-1 core protein) was investigated in primary hepatic carcinoma (25 cases of cholangiocarcinoma, 15 cases of combined hepatocellular-cholangiocellular carcinoma and 18 cases of hepatocellular carcinoma) with monoclonal antibody DF3 and a standard avidinbiotin complex method. MUC-1 core protein was almost always expressed in cholangiocarcinoma and in the cholangiocarcinoma area of hepatocellular-cholangio-cellular carcinoma to a varied degree, whereas such expression was virtually absent in hepatocellular carcinoma and the hepatocellular carcinoma areas of hepatocellular-cholangiocellular carcinoma. Nonneoplastic intrahepatic biliary epithelium, as well as hepatocytes, was virtually negative for this protein. In well-differentiated cholangiocarcinoma, this protein tended to be expressed on luminal surfaces, whereas poorly differentiated cholangiocarcinoma showed cell membranous or diffuse cytoplasmic staining patterns. Double staining with Alcian blue (pH 2.5) and immunostaining for MUC-1 core protein showed that although some parts of cancerous areas were positive for both stains, most cancerous areas were only positive for one. Alcian blue--positive areas were dominant over MUC-1 core protein--expressing areas in well-differentiated cholangiocarcinoma, whereas the reverse was the case in poorly differentiated cholangiocarcinomas and also in cholangiocarcinoma areas of hepatocellular-cholangiocellular carcinoma. This study is the first report to document that cholangiocarcinoma and cholangiocarcinoma areas of hepatocellular-cholangiocellular carcinoma express MUC-1 core protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical study of mucin carbohydrates and core proteins in hepatolithiasis and cholangiocarcinoma

The expression of mucin carbohydrates [Tn, sialosyl-Tn(STn), and T antigens] and core proteins [MUCI-apomucin-related antigen (ARA) and MUC2-ARA] was examined immunohistochemically in tissues from 40 patients with hepatolithiasis and 26 patients with intrahepatic bile-duct carcinoma. Tn and STn antigens were expressed in most of the carcinomas, and were also often expressed in the atypical bile-duct epithelium of the patients with hepatolithiasis or carcinoma, whereas they were rarely or never expressed in the normal bile duct, suggesting that they are effective tumor markers. T antigen was less useful as a marker for intrahepatic bile-duct carcinoma or the atypical epithelium, because it was expressed in normal bile-duct of some cases. Regarding the expression of ARAs in the carcinomas, non-invasive bile-duct cyst adenocarcinomas with favorable prognosis either expressed no MUCI-ARA with [DF3(-), MUSEII(-) and 139H2(-)] staining pattern or expressed MUCI-ARA with [DF3(-), MUSEII(+) and 139H2(+)] staining pattern. However these tumors often expressed MUC2-ARA with [anti-MRP(+) and CCP58(+)] staining pattern. In contrast, most invasive non-papillary cholangiocarcinomas with poor prognosis expressed MUCI-ARA with [DF3(+), MUSEII(+) and 139H2(+)] staining pattern, but expressed no MUC2-ARA with [anti-MRP(-) and CCP58(-)] staining pattern. These results suggests that different apomucins are produced by bile-duct cystadenocarcinomas and cholangiocarcinomas with differing prognosis. Furthermore, expression of Tn and STn antigens is a useful indicator of malignancy in the intrahepatic duct.