Expression of MUC1 and MUC2 mucins in extrahepatic bile duct carcinomas: its relationship with tumor progression and prognosis

Our previous immunohistochemical studies in the pancreas, intrahepatic bile duct, and ampulla of Vater demonstrated that an invasive carcinoma with a poor outcome showed a pattern of MUC1 (membrane-bound mucin) positive and MUC2 (intestinal-type secretory mucin) negative, whereas many of the non-invasive tumors with favorable outcome showed a pattern of MUC1 negative and MUC2 positive. The aim of this study is to compare the expression profiles of MUC1 and MUC2 mucins in extrahepatic bile duct carcinomas to gain insight into the relationship between the biological nature of the carcinomas and the role of mucins. We examined the expression profiles of MUC1 of different glycoforms and MUC2 in 60 extrahepatic bile duct carcinomas using immunohistochemistry.The expression of MUC1/CORE (core peptide of MUC1), MUC1/DF3 (core peptide of MUC1 with sialyl oligosaccharides) and MUC1/MY.1 E12 (sialylated MUC1) showed a significant relationship with tumor progression factors such as poor differentiation, deep invasion, lymph node metastasis, lymphatic invasion or perineural invasion. In contrast, the expression of MUC1/HMFG-1 (fully glycosylated MUC1) did not show a significant relationship with the tumor progression factors. In the different glycoforms of MUC1 examined, the expression of MUC1/DF3 and MUC1/MY.1E12 was related with the poor outcome of the patients. In contrast, the expression of MUC2 was inversely related with the tumor progression factors and poor outcome. In the 52 patients with advanced tumors, only MUC1/DF3 high expression correlated with poor prognosis. In conclusion, MUC1/DF3 was the most useful prognosis indicator among the various glycoforms of MUC1 mucins.     

Expression of MUC5AC in colorectal carcinoma and relationship with prognosis

Overexpression and alterations in the glycosylation of gastric mucins have been described in colorectal carcinoma. The purpose of our study was to confirm aberrant expression of MUC5AC in colorectal carcinoma, to investigate relationships between clinicopathological parameters and MUC5AC expression, and to determine if MUC5AC expression may be a prognostic factor for colorectal carcinoma. Immunohistochemical staining using an antibody against MUC5AC tandem repeat epitopes was performed on colorectal tumor specimens (n = 41), their metastatic tumors in regional lymph nodes (n = 21) and normal colonic mucosa (n = 41). We also documented clinicopathological parameters such as the age and sex of the patient, location, size, Dukes stage, histological type and grade of the tumor, pre-sence and number of metastatic lymph nodes, lymphatic, venous and perineural invasion, presence of preoperative and postoperative metastatic tumors and tumor recurrence. MUC5AC was expressed in 34.1% of tumor samples, 24.4% of normal colonic mucosa samples and 19% of lymph node metastases. MUC5AC showed ectopic expression in colorectal carcinoma and was also expressed strongly in mucinous carcinoma (60%). The number of tumors that expressed MUC5AC was lower in patients older than 60 years, in rectum-localized tumors and in patients who had evidence of recurrence and/or metastasis in the postoperative period. The patients with MUC5AC-negative tumors had a lower incidence of being disease free and of overall survival. In conclusion, the patients with MUC5AC-negative tumors had poor clinicopathological parameters and showed worse survival than patients with MUC5AC-positive tumors. Absence of MUC5AC expression in tumors can be a prognostic factor for more aggressive colorectal carcinoma.     

Expression of MUC1 and MUC2 mucins in gastric carcinomas: their relationship with clinicopathologic parameters and prognosis

The aim of this study was to investigate the relationship between MUC1 and MUC2 mucin expressions and clinicopathologic variables in gastric carcinomas with regard to survival times. MUC1 and MUC2 expressions were revealed immunohistochemically in 143 gastric carcinomas. Of these 143 patients, follow-up data were available for 45 (median survival time of 30 months, ranging from 2 to 80 months). MUC1 was detected in 82 (58%), and MUC2 in 60 (42%) out of 143 cases. Papillary adenocarcinomas showed significantly higher MUC1 and MUC2 immunoreactivity than did signet-ring cell and mucinous tumors (p = 0.045 and p = 0.01, respectively). MUC1 was highly positive in intestinal-type carcinomas (p = 0.006), whereas intestinal and diffuse carcinomas did not differ in MUC2 expression. There was a positive correlation between tumor differentiation and MUC1 expression. However, no correlation was found between MUC1 and MUC2 expressions and angiolymphatic invasion. According to the TNM classification, stage 1A tumors have significantly lower rates of MUC1 reactivity compared to higher stages (p = 0.04). The patients with gastric carcinomas expressing MUC1 showed significantly poorer survival than those without MUC1 expression (p = 0.04). The present study suggests that MUC1 expression be a useful prognostic factor for predicting the outcome of gastric carcinoma patients, whereas the role of MUC2 expression is still unclear.     

黏蛋白MUC1和MUC2联合表达与大肠癌的相关性

目的探讨黏蛋白MUC1和MUC2在大肠腺癌中的分型及其与临床各个病理参数之间的关系。方法用免疫组织化学S-P法对20例切端肠黏膜、31例癌旁组织及60例大肠腺癌进行黏蛋白MUC1、MUC2检测。结果在上述3者中，黏蛋白MUC1阳性表达率分别为17．62％、25．81％、46．67％(P=0．019)；MUC2阳性表达率分别为100％、87．1％、58．33％(P-0．000)。根据MUC1和MUC2在大肠腺癌中的表达把大肠腺癌分为4型：MUC2 ／MUC1-、MUc2 ／MUC1 、MUC2-／MUC1 、MUC2-／MUC1-，其中MUC2 ／MUC1-型与淋巴结转移、Dukes分期以及生存期具有明显的相关性；MUC2 ／MUC1 型与各个临床病理参数均不具有相关性；MUC2-／MUC1 型与发生部位、淋巴结转移、Dukes分期具有相关性；MUC2-／MUC1-犁与生存期具有相关性。结论MUC1的上调表达或MUC2的下调表达可能参与了大肠腺癌的发生，各型大肠腺癌与肿瘤的发展、浸润及转移相关，对临床上判断预后具有较大的意义。     

Expression of MUC1 and MUC2 mucin core proteins and their messenger RNA in gall bladder carcinoma: an immunohistochemical and in situ hybridization study

Expression of mucin core protein MUC1 and MUC2 was examined at the protein and mRNA level in 55 cases of carcinoma and 20 of dysplasia, and in 15 non-dysplastic epithelia of the gall bladder. In non-dysplastic epithelium, MUC1 protein was not expressed, while in dysplasia, MUC1 was focally expressed in ten cases, particularly in those associated with carcinoma. In carcinoma, MUC1 was expressed heterogeneously, and the frequency and extent of MUC1 expression increased with histological dedifferentiation. MUC1 was found on the apical cell surface and also in the cytoplasm in well- and moderately-differentiated carcinoma, and on the cell border in poorly-differentiated cases. In infiltrative regions, MUC1 expression was more predominant and MUC1 frequently leaked outside the foci of carcinoma. By contrast, MUC2 was focally expressed in non-dysplastic as well as in dysplastic epithelia and more frequently in well-differentiated adenocarcinoma. MUC2-positive cells resembled goblet cells, whether in non-dysplastic epithelium, dysplasia or carcinoma. Cell proliferative activity was higher in MUC1-positive than in MUC1-negative carcinoma cells. Distributions of MUC1 and MUC2 mRNA signals and of MUC1 and MUC2 proteins were similar in carcinoma and dysplasia. These results suggest that MUC1 expression by gall bladder carcinoma may reflect histological dedifferentiation, increased proliferative activity, and invasiveness, while MUC2 expression is related to lower proliferative activity and reflects some differentiation towards goblet cells; and that MUC1 expression in gall bladder dysplasia reflects malignant transformation. Copyright © 1999 John Wiley & Sons, Ltd.     

MUC5B expression in gastric carcinoma: relationship with clinico-pathological parameters and with expression of mucins MUC1, MUC2, MUC5AC and MUC6

The tissue microarray technology is a high-throughput technique that allows studies of multiple markers in large tumor materials. We performed immunohistochemical profiling using tissue microarray and immunostaining for Ki-67, p53, bcl-2, CD44, cyclin A and Pgp in a series of 211 malignant fibrous histiocytomas (MFHs) with correlation to prognosis. Tissue from 50 local recurrences and 20 metastases was available for comparison with the primary tumors. In univariate analysis, Ki-67 was the only immunohistochemical marker significantly correlated with metastasis with a hazard ratio of 1.9. Multivariate analysis, with tumor size, depth, necrosis, vascular invasion, mitotic rate and Ki-67 expression, revealed an independent prognostic value of tumor size and Ki-67. Local recurrences did not differ from the corresponding primary tumors, whereas metastases showed a trend for upregulation of cyclin A and Pgp. In this large series of MFHs, a tumor size greater than 8 cm and a Ki-67 index of more than 20% were strong and independent prognostic factors for metastasis. In contrast, p53, bcl-2, CD44, cyclin A and Pgp, which have previously been suggested as prognostic factors in soft tissue sarcomas, did not show such correlations. Hence, we suggest that proliferation, as measured by Ki-67 index, should be considered as a prognostic marker in clinical management of pleomorphic soft tissue sarcomas.     

Expression of MUC2, MUC5AC and MUC6 apomucins in carcinoma, dysplasia and non-dysplastic epithelia of the gallbladder

To date, nine apomucins have been characterized and their expression in malignant and premalignant lesions is under evaluation. The purpose of this study was to characterize immunohistochemically the expression of MUC2 (colonic/ intestinal type), MUC5AC (gastric surface type), and MUC6 (pyloric gland type) apomucins in 55 patients with gallbladder carcinoma (10 with in situ carcinoma, 45 with invasive carcinoma), 20 patients with gallbladder dysplasia, and 15 patients with non-dysplastic gallbladder. MUC2 was expressed mainly in 'goblet type' cells. The frequency was increased in non-dysplastic gallbladder (47%), dysplasia (75%), and in situ carcinoma (100%), and decreased in invasive carcinoma (58%). Carcinoma cells expressing MUC2, which were usually distributed at superficial areas, and well-differentiated carcinoma expressed MUC2 more extensively than moderately and poorly differentiated ones. MUC5AC was frequently expressed in gallbladder irrespective of non-dysplastic epithelia, dysplasia and carcinoma. MUC5AC was expressed also in carcinoma cells at deeply invasive sites. MUC6 was expressed frequently in pseudopyloric gland metaplasia as well as dysplasia and carcinoma. In conclusion, non-dysplastic gallbladder has a similar phenotype to gastric pyloric mucosa. Gallbladder carcinoma exhibits both intestinal and gastric surface phenotypes in the early stage of carcinogenesis, with the gastric surface phenotype dominant in invasive carcinoma.     

Expression Of Ki-67 and MUC1 In mucoepidermoid carcinomas of young and adult patients: prognostic implications

Mucoepidermoid cancer (MEC) is the most malignant neoplasm of minor salivary glands. The aim of this study was to compare the expression of Ki-67 and MUC1 and clinicopathological data of mucoepidermoid carcinoma (MEC) in minor salivary glands of young and adult patients. The MEC cases in patients under 25 years old (n = 8) and over 26 year old (n = 8) were matched by gender, location and TNM staging. Immunohistochemical analysis of Ki-67 and MUC1 was carried out and correlated with clinicopathological data. The expression of Ki-67 and MUC1 was similar between the groups, although a tendency towards higher Ki-67 and MUC1 expression was observed in the younger group. Despite no significant differences, survival time was shorter in adults (71.37 ± 17.44 months) compared to the younger group (97.62 ± 25.81). While no patient deaths or tumor recurrences were found in the younger patient group, the adult group presented recurrence in 25% of cases and one patient died. In conclusion, our findings showed that age can be an important factor in MEC prognosis.     

卵巢浆液性和黏液性肿瘤MUC1、MUC2的表达及其意义

目的探讨卵巢浆液性和黏液性肿瘤中黏蛋白MUC1、MUC2的表达与临床病理特征的相关性。方法免疫组化S—P法检测90例卵巢浆液性和黏液性肿瘤的黏蛋白MUC1、MUC2的表达,并对其中50例恶性病例作生存分析。结果（1）交界性与恶性卵巢肿瘤中黏蛋白MUC1的表达阳性率明显高于良性肿瘤,差异有显著性（P〈0．001）;黏蛋白MUC1与WHO病理分级、FIGO临床分期、大网膜转移显著相关（P〈0．05）。（2）黏蛋白MUC2与组织学类型、WHO病理分级相关（P〈0．05）。（3）黏蛋白MUC1与MUC2呈负相关（P〈0．05）。（4）对50例恶性浆液性和黏液性肿瘤进行的生存分析中,单因素分析显示：WHO病理分级、FIGO临床分期、大网膜转移、MUC1表达程度与预后相关（P〈0．05）,而多因素分析中只有FIGO临床分期、MUC1表达程度具有独立的预后意义（P〈0．05）,Kaplan—Meier生存曲线分析显示,Ⅲ、Ⅳ期较Ⅰ、Ⅱ期生存率差异有显著（P〈0．01）,MUC1阳性组和阴性组生存率差异有显著性（P〈0．01）。结论黏蛋白MUC1、MUC2与恶性卵巢浆液性和黏液性肿瘤的浸润、转移相关,Ⅲ、Ⅳ期肿瘤、MUC1强表达可作为恶性卵巢浆液性和黏液性肿瘤预后不良的可行性指标。     

Comparative evaluation of the prognostic value of MUC1, MUC2, sialyl-Lewis(a) and sialyl-Lewis(x) antigens in colorectal adenocarcinoma

AIMS: The significance of MUC1, MUC2 and sialylated Lewis blood group antigens as prognostic markers in colorectal adenocarcinoma was investigated in a large series of patients because previous investigations revealed inconsistent results due to unrelated tumour samples from different patient groups and methodological differences. METHODS AND RESULTS: Tissues from 243 patients with colorectal adenocarcinoma were stained immunohistochemically. MUC1 showed a strong immunoreactivity (in more than 35% of the tumour area) in 32.5%, MUC2 in 51.0%, sialyl-Lewis(x) in 67.9% and sialyl-Lewis(a) in 73.7% of the cases, respectively. MUC1 immunoreactivity displayed a significant correlation with tumour progression as reflected by advancing pTNM staging and poor differentiation. MUC2 expression was significantly stronger in mucinous adenocarcinomas. Sialyl-Lewis(x) immunostaining correlated with the extent of lymph node metastasis as well as low cytological differentiation. According to univariate and multivariate analysis (P < 0.0001) only MUC1 reactivity represented a marker of worse survival probability, opposed to the sialylated Lewis antigens that did not exert a predictive value. CONCLUSIONS: According to our data, MUC1 and sialyl-Lewis(x) immunoreactivity exhibit statistically significant correlations with established markers of tumour progression. However, only MUC1 presents as an independent prognostic factor of colorectal adenocarcinoma.     

MUC1, MUC2 and MUC5AC expressions in cardiac myxoma

Background Cardiac myxoma, the most common primary tumor of the heart, has a variable clinical presentation and immunohistochemical profile. An abundant mucopolysaccharidic matrix exists, including mucin, within cardiac myxoma. This investigation first reports the expressions of mucin genes in cardiac myxoma.Methods A retrospective study was conducted between December 1976 and February 2003, comprising 101 consecutive patients with cardiac myxoma who were treated with surgical excision. Detailed clinical parameters also were reviewed. Mucin genes, namely MUC1, MUC2 and MUC5AC, were studied immunohistochemically in 47 randomly selected patients.Results The study group contained 57 (57%) women and 44 (43%) men, with a mean age of 38±21 years. Their presentations included: asymptomatic (41%), dyspnea (35%), stroke (23%), chest pain (7%), fever (6%), syncope (5%) and tricuspid regurgitation (70%). The sample included 90 myxoma located in the left atrium, 3 (3%) recurrent myxoma and 8 (8%) myxoma not located in the left atrium. The myxoma did not differ with location or clinical event in terms of pathological scores, such as vascular proliferation, inflammation, cellularity, hyaline, calcification and thrombosis. Cardiac myxoma is characterized by excessive mucus secretion. Expression of membrane-associated MUC1 was considerably higher than that of the secreted mucins, MUC2 and MUC5AC (P<0.05). Furthermore, expression of MUC5AC is related to lesser embolism (P<0.05).Conclusions This work first examined the immunohistochemical expression of mucin (MUC1, MUC2 and MUC5AC) in cardiac myxoma. This investigation then showed that the expression of representative membrane-associated mucin, MUC1, and/or secretory mucins, MUC2 and MUC5AC, in cardiac myxoma was associated with important tumor clinicopathological characteristics. Moreover, MUC5AC appears related to lesser embolism. This approach can help distinguish the potential roles of secretory mucins versus membrane-associated mucins in the development of cardiac myxoma.     

Positive correlation of expression of L-type amino-acid transporter 1 with colorectal tumor progression and prognosis: Higher expression in sporadic colorectal tumors compared with ulcerative colitis-associated neoplasia

The role of L-type amino-acid transporter 1 (LAT1), an oncofetal protein, in tumor progression is not well known, although it is important for the survival and proliferation of cancer cells. LAT1 expression was immunohistochemically analyzed and compared in sporadic (conventional) colorectal tumors and ulcerative colitis (UC)-associated neoplasia development and progression. LAT1 expression showed a significant stepwise increase in the order: conventional low-grade tubular adenoma, high-grade tubular adenoma, and invasive adenocarcinoma. Similarly, the same increasing trend in LAT1 expression was found in UC-associated low-grade dysplasia, high-grade dysplasia, and adenocarcinoma, whereas expression was significantly lower compared with that in an adenoma–adenocarcinoma series. LAT1 expression was predominant in the upper half of mucosal lesions in low-grade adenoma. This localized difference in LAT1 expression between the upper and lower halves of mucosal lesions disappeared in conventional high-grade adenoma and adenocarcinoma. LAT1 expression in the colorectal mucosa was significantly increased in the order: nontumor mucosa, quiescent phase of UC, and active phase of UC. Considering the histological pattern of Ki-67 labeling, LAT1 expression appeared partly related to cell proliferation, but this was not significant. In relation to the prognosis of patients with sporadic phase IV colorectal adenocarcinoma, this was significantly poorer in the group with high LAT1 expression compared with that with low LAT1 expression. This suggests LAT1 expression may be used as a companion biomarker for anti-cancer therapy targeting the LAT1 molecule in colorectal cancers.     

Expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma: an immunopathological study with clinical correlation

AIMS: Changes in the histochemical characteristics of the surface epithelial mucins is the hallmark of Barrett's metaplasia. The study investigated the pattern of expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma as possible indicators of increased malignant potential. METHODS AND RESULTS: Tissue sections from 51 patients with Barrett's intestinal metaplasia, nine with dysplasia (three indefinite) and 28 resected adenocarcinomas were stained with monoclonal antibodies to MUC1 and MUC2. The majority of the patients were men (70/88, 80%) who were treated over a period of 3 years. None of the patients with dysplasia or carcinoma were under surveillance at the time of presentation. All 51 biopsies with Barrett's metaplasia expressed MUC2 and MUC1 was consistently absent. Neither MUC1 or MUC2 were expressed in the dysplastic epithelium whether in its pure form (6/6) or when associated with carcinoma (26/28) (P < 0.005). Three biopsies which were initially classified as high-grade dysplasia expressed MUC1 and these turned out to be carcinomas on further investigations. MUC1 was also expressed in 12/28 (43%) of the adenocarcinomas and majority of these were poorly differentiated stage 3 tumours (P < 0.05). MUC2 was only positive in mucin-secreting carcinomas (4/28; 14%) irrespective of the tumour stage. CONCLUSION: Despite the large number of patients with Barrett's metaplasia and carcinoma, very few patients presented with dysplasia, implying that Barrett's oesophagus is a silent disease in the community presenting late as carcinoma. The study has demonstrated aberrant expression of MUC2 (an intestinal mucin) in Barrett's metaplasia and this expression is lost when the cells become dysplastic. The lack of MUC1 in dysplastic epithelium and its expression in carcinoma could be utilized as a marker which could differentiate dysplasia from carcinoma in mucosal biopsies. Furthermore, expression of MUC1 in advanced stage oesophageal cancers (as in breast cancer) suggests an unfavourable prognosis.     

Expression of mucins (MUC1, MUC2, MUC5AC and MUC6) in mucinous carcinoma of the breast: comparison with invasive ductal carcinoma

AIMS: Mucinous carcinoma of the breast usually shows less frequent lymph node metastasis and more favourable outcome compared with invasive ductal carcinoma. The aim of this study is to compare the expression profiles of several mucins in mucinous carcinomas and invasive ductal carcinomas to gain insight into the relationship between the less aggressive biological nature of mucinous carcinoma and the role of mucins. METHODS AND RESULTS: We examined the expression profiles of MUC1 (membrane-bound mucin) of different glycoforms (from non-glycosylated form to fully glycosylated form), MUC2 (intestinal type secretory mucin), MUC5AC (gastric surface type secretory mucin) and MUC6 (gastric pyloric gland type secretory mucin) in 17 mucinous carcinomas and 46 invasive ductal carcinomas using immunohistochemistry. Various glycoforms of MUC1 were expressed frequently in both mucinous carcinomas (65-100%) and invasive ductal carcinomas (92-100%), although non-glycosylated MUC1 (MUC1/CORE) and fully glycosylated MUC1 (MUC1/HMFG-1) showed significantly lower expression rates in mucinous carcinomas compared with those in invasive ductal carcinomas. The expression rates of MUC2 (94%) and MUC6 (71%) in mucinous carcinomas were significantly higher than those of MUC2 (15%) and MUC6 (15%) in invasive ductal carcinomas. There was no significant difference in the expression rate of MUC5AC in mucinous carcinomas (12%) and that in invasive ductal carcinomas (4%). CONCLUSIONS: The expression rate of MUC1/CORE and MUC1/HMFG-1, which is related to poor prognosis in the gastric and colorectal cancers, is low in mucinous carcinomas. The high expression rate of gel-forming secretory mucins (MUC2 and MUC6) in mucinous carcinoma suggests that high production of these types of mucins may act as a barrier to cancerous extension resulting in their less aggressive biological behaviour.     

食管鳞状细胞癌中MCM2蛋白与Ki-67的表达及对比研究

目的 探讨微小染色体维持蛋白2(minichromosome maintenance 2 protein,MCM2)与Ki-67在食管癌中的表达及两者表达的差异和相关性.方法 采用免疫组化EliVision方法,分别检测90例食管鳞状细胞癌组织中MCM2,Ki-67的表达,计算其标记指数(labeling index,LI),分析MCM2,Ki-67在食管鳞癌中的表达及两者之间的差异和相关性.结果 90例食管癌组织均表达MCM2及Ki-67抗原,其中MCM2 LI高于Ki-67,两者差异有统计学意义(P＜0.05).同时显示MCM2及Ki-67的表达与食管鳞癌的分化程度具有相关性,MCM2在食管鳞癌各级组织间表达差异均有统计学意义(P＜0.01),而Ki-67只在Ⅰ级与Ⅲ级食管鳞癌组织间差异有统计学意义(P＜0.01).并且MCM2与Ki-67在食管鳞癌中的表达呈正相关关系(P＜0.01).结论 MCM2是优于Ki-67的细胞增殖标记物,可用于对食管鳞癌的分级和判断食管鳞癌恶性程度的高低.     

MUC2, MUC5AC and MUC5B in the mucus of a patient with pseudomyxoma peritonei: biochemical and immunohistochemical study

A 58-year-old man with a 1 year history of progressive abdominal distension underwent a laparotomy for pseudomyxoma peritonei. The mucin was identified and characterized in the present study. Approximately 6 L of crude mucus in the sol (highly viscous) and gel (semisolid) phases was obtained from the patient's peritoneal cavity. The sol material was briefly homogenized followed by slow stirring at dilutions of up to 1:10 with 6 mol/L guanidinium chloride and proteolytic inhibitors for periods of up to 48 h. Preparative and analytical gel filtration on Sepharose 2B showed some PAS-positive material eluting in the void volume accompanied by equal or larger amounts of protein in the void and included volumes of the columns. Sodium dodecylsulfate-polyacrylamide gel electrophoresis of purified mucin on a 4-20% gradient gel showed PAS-positive material on the top of the running gel and a distinct smaller-sized species of mucin of higher electrophoretic mobility with background material in between the large and small mucin. Western blot (confirmed by immunohistochemical analysis) after agarose gel electrophoresis showed the presence of MUC2, MUC5AC and MUC5B in the mucus. There was no MUC1, MUC1core or MUC6 in the tissue. Histopathological examination confirmed a mucinous appendicular adenocarcinoma. Histology showed the mucin to be predominantly of the sulfated and non-sulfated acidic type. Serine, threonine and proline comprised 21.6% of the total amino acid composition of the sample. The viscous nature of the material is due to the presence of three gel-forming mucins and possibly to its high content of protein.