Home | About IJMPO | Editorial board | Search | Ahead of print | Current Issue | Archives | Instructions | Subscribe | Advertise | Contact us |  Login 
Indian Journal of Medical and Paediatric Oncology
Search Article 
  
Advanced search 
 

 Table of Contents      
ORIGINAL ARTICLE
Year : 2019  |  Volume : 40  |  Issue : 3  |  Page : 402-405  

MUC2 and MUC5AC expression in colon cancer: A preliminary report from South India


1 Department of Medical and Surgical Gastroenterology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
2 Glycotechnology Centre, AC Tech, University of Madras, Chennai, Tamil Nadu, India
3 Gleneagles Global Health City, Chennai, Tamil Nadu, India
4 Department of Medical and Surgical Gastroenterology, Stanley Medical College and Hospital; Gleneagles Global Health City, Chennai, Tamil Nadu, India

Date of Submission09-Feb-2018
Date of Decision01-Mar-2018
Date of Acceptance12-Sep-2018
Date of Web Publication04-Dec-2019

Correspondence Address:
Mayank Jain
Gleneagles Global Health City, Chennai - 600 100, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijmpo.ijmpo_33_18

Rights and Permissions
  Abstract 

Background: There is scanty data from India regarding MUC protein expression from colorectal cancers (CRC) among Indian patients. Aim of the Study: The aim of this study is to assess the alterations in the expression of MUC2 and MUC5AC in 25 patients with CRC by site of the tumor location and differentiation at histology. Materials and Methods: Patients with proven adenocarcinoma of the colon alone were included for the study. Biopsy specimens obtained from tumorous lesions in the colon were classified based on histopathology as well differentiated, moderately, and poorly differentiated adenocarcinoma. Immunohistochemistry was done in the 4 μm thick sections to identify the expression of MUC2 and MUC5AC mucins. Results: MUC2 was uniformly expressed with near similar intensity while MUC5 was moderately (56%) to highly expressed (36%) in mucinous tumors. In nonmucinous tumors, MUC2 was least expressed (68%) with a significant expression on MUC5AC (88%). Except for rectosigmoid growth which had greater expression of MUC5AC (31%), both proximal and distal carcinomas had significant MUC2 and MUC5AC expression. Conclusion: MUC2 and MUC5AC are expressed in colonic cancers, the former showing mildtomoderate expression and the latter moderatetointense expression. The expression is more in mucinous adenocarcinoma.

Keywords: Cancer, colon, India, mucin


How to cite this article:
Jayanth R, Devaraj H, Surendran R, Jain M, Venkataraman J. MUC2 and MUC5AC expression in colon cancer: A preliminary report from South India. Indian J Med Paediatr Oncol 2019;40:402-5

How to cite this URL:
Jayanth R, Devaraj H, Surendran R, Jain M, Venkataraman J. MUC2 and MUC5AC expression in colon cancer: A preliminary report from South India. Indian J Med Paediatr Oncol [serial online] 2019 [cited 2020 Jan 22];40:402-5. Available from: http://www.ijmpo.org/text.asp?2019/40/3/402/272260


  Introduction Top


One of the strongest prognostic parameter in colorectal cancer (CRC) is tumor node metastasis staging and is currently used as a guide to patient management. However, biological behavior of the tumor with same pathological grading may have different clinical outcomes, and hence, there is a need for identifying other prognostic markers that can stratify patients for different therapeutic and surveilance strategies.

Epithelial surfaces, including the colonic epithelium, are covered and protected by mucus, of which the major glycoprotein constituents are mucins, large carbohydrate-rich glycoproteins. Besides their protective function in the normal colon, alterations in mucin are a common feature of colonic neoplasia.[1] Expression profiles of mucin may play a role in prognosis and tumor phenotypes.[2]

Mucins are high-molecular-weight glycoproteins expressed by epithelial tissues and are synthesized throughout the gastrointestinal tract (GIT) by the epithelial cells and form a protective barrier on the surface. Constituents of mucin include clustered oligosaccharides. They form a mucosal protecting system on the surface of the GIT. Recent studies have characterized the mucin protein. Since the initial characterization of cDNA sequences of MUC1[3],[4],[5] and MUC2,[6] several genes encoding mucin proteins have been identified and named chronologically as MUC1 through MUC17.

Several types of MUC proteins have been described. These include secreted gel-forming mucins (MUC2, MUC5AC, and MUC6), transmembrane mucins (MUC1), and others that do not fit into either of the two classes. Organ-specific mucin has been identified. MUC1 is expressed in apices of most epithelial cells.[7] MUC2, for example, is present in the goblet cells of the small and large intestine, MUC5AC, and MUC6 are especially expressed in the gastric epithelium and rarely in the colon.[4],[5],[6]

During a neoplastic transformation or progression of a benign polyp to a malignant one, expression of specific mucins can be reduced or the organ specificity may be lost, and still more, there may be an aberrant expression of new mucins. For example, MUC5AC can be aberrantly expressed by colorectal polyps and carcinoma. It has been hypothesized that aberrant expression of MUC5AC in CRC tissues increased the overall survival of these patients. Mucin 2 (MUC2) is known to undergo significant changes during malignant transformation of colorectal tumor.[8] While MUC2 downregulation is noted in nonmucinous adenocarcinomas, there is upregulation of MUC2 in mucinous adenocarcinomas.

Our study aimed to assess the alterations in the expression of MUC2 and MUC5AC in 25 patients with CRC by site of the tumor location and differentiation at histology. These were compared with five healthy controls.


  Materials and Methods Top


Patients with proven adenocarcinoma of the colon alone were included for the study. Biopsy specimens obtained from tumorous lesions in the colon were classified based on histopathology as well differentiated, moderately, and poorly differentiated adenocarcinoma. Immunohistochemistry was done in the 4 μm thick sections to identify the expression of MUC2 and MUC5AC mucins. The slides were dewaxed in xylene and treated in descending grades of ethanol (100%, 90%, 70%, 50%, and 30%). The sections were then treated with 3% hydrogen peroxide in methanol. Antigen retrieval was done in citrate buffer (pH-6.0) for 5 min followed by blocking with 3% bovine serum albumin in phosphate-buffered saline (PBS). The sections were probed with the respective primary antibodies for MUC2 and MUC5AC [Flowchart 1].



After an overnight incubation at 4°C, the tissues were washed in PBS and then incubated with Horseradish Peroxidase conjugated secondary antibody for 1 h at room temperature. The antigen-antibody reaction was visualized using 3,3'–diaminobenzidine chromogen in dim conditions. Counterstaining was done using hematoxylin. The slides were then dehydrated in an ascending series of ethanol (30%, 50%, 70%, 90%, and 100%), cleared in xylene and mounted. After drying, the sections were visualized in Axioscope Two Plus Microscope (Carl Zeiss).

The results of the staining were semi-quantitatively evaluated for the percentage and intensity of the positive cells. An intensity value of −, +, ++, and +++ were classified as negative, mild, moderate, and intense, respectively [Figure 1]a, [Figure 1]b, [Figure 1]c.
Figure 1: (a) Nonmucinous colorectal cancer probed for MUC2 and MUC5AC (b) Mucinous colorectal cancer showing MUC5AC expression (c) Mucinous colorectal cancer MUC 2 expression

Click here to view


Ethics committee of the institution approved the study.


  Results Top


The mean age of the 25 patients with CRC was 51 years. Men outnumbered the women in a ratio of 3:1. All had proven adenocarcinoma.

Immunohistochemical analysis of MUC2 and MUC5AC expression

Among healthy controls, all five participants showed MUC2 expression, and none showed MUC5AC expression. MUC2 was uniformly expressed with near similar intensity while MUC5 was moderately (56%) to highly expressed (36%) in mucinous tumors. In nonmucinous tumors, MUC2 was least expressed (68%) with significant expression on MUC5AC (88%) [Figure 1] and [Table 1].
Table 1: Mucin expression in mucinous and mucinous carcinomas

Click here to view


MUC expression based on location and histology (mucinous versus nonmucinous)

Of the 25 patients with CRC, 13 (52%) were localized to the rectosigmoid region, and 24% each in proximal-caecum and ascending colon (6) and distal-transverse and descending colon (6). Irrespective of mucinous (28%) or nonmucinous (72%) nature of tumour, except for rectosigmoid growth which had greater expression of MUC5AC (31%), both proximal (100%) and distal carcinomas (50%–67%) had a significant MUC2 and MUC5AC expression [Table 2].
Table 2: Mucin expression based on location and mucin production

Click here to view



  Discussion Top


Most organs in our body seem to synthesize more than one type of mucin, although a particular mucin type may predominate in a particular organ. One common characteristic of gastrointestinal tumors is loss of this organ specificity. For example, there is an aberrant expression of gastric-type mucin (MUC5AC) in colorectal adenomas, a precursor of some colon cancers, and aberrant expression of colonie-type mucin (MUC2) in gastric intestinal metaplasia, a precursor of some gastric cancers. Immunohistochemistry is a widely accepted and well-documented method for characterizing patterns of protein expression while preserving tissue and cellular architecture.[7]

In the present study, normal colonic specimens showed MUC2 expression. In colonic carcinoma, majority had mild-to-moderate expression and only one showed intense expression. In addition, MUC2 expression was decreased in nonmucinous colorectal adenocarcinoma, but preserved in mucinous carcinomas. This finding is consistent with other studies.[9],[10],[11],[12] A reduced MUC2 expression in colon cancer contributes to the prosurvival pathway in cells; MUC2 staining is inversely associated with p53 expression in mucinous carcinoma,[13] the latter regulates MUC2 transcription.

None of the normal participants showed MUC5AC expression. Majority of the cases (88%) showed moderate-to- high expression, especially in mucinous carcinomas. MUC5AC is usually expressed in well-differentiated tumors[9],[14] and correlates with better survival.

Recent studies have correlated MUC expressions with the tumor invasion and location. Expression of MUC2, MUC5AC, and MUC6 was strongly associated with features associated with tumorigenesis through the serrated neoplasia pathway, proximal location, poor differentiation, lymphocytic response, and increased T stage (all P < 0.001).[15]

Correlation of proximal location with MUC 2 and MUC5AC expression is noted in the present study too. Loss of MUC2 expression has been reported to be a predictor of adverse outcome. Aberrant expression of MUC5AC and MUC6 have been associated with favorable outcome in CRC.[16]

The present study highlights MUC protein with special reference ot MUC2 and MUC5AC in colonic cancers, the former showing mild-to-moderate expression and the latter moderate-to-intense expression and more so in mucinous adenocarcinoma. The present study was essentially a cross-sectional study and did not aim at a serial follow-up of our patients. Future studies can enlighten on its role as a marker in predicting invasiveness, prognostication, and survival benefits. Further, profiling of MUC expression may be helpful for histological subtyping and in the development of future targeted therapies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Byrd JC, Bresalier RS. Mucins and mucin binding proteins in colorectal cancer. Cancer Metastasis Rev 2004;23:77-99.  Back to cited text no. 1
    
2.
Aksoy N, Corfield AP, Sheehan JK. Preliminary study pointing out a significant alteration in the biochemical composition of MUC2 in colorectal mucinous carcinoma. Clin Biochem 2000;33:167-73.  Back to cited text no. 2
    
3.
Gendler SJ, Lancaster CA, Taylor-Papadimitriou J, Duhig T, Peat N, Burchell J, et al. Molecular cloning and expression of human tumor-associated polymorphic epithelial mucin. J Biol Chem 1990;265:15286-93.  Back to cited text no. 3
    
4.
Lan MS, Batra SK, Qi WN, Metzgar RS, Hollingsworth MA. Cloning and sequencing of a human pancreatic tumor mucin cDNA. J Biol Chem 1990;265:15294-9.  Back to cited text no. 4
    
5.
Ligtenberg MJ, Vos HL, Gennissen AM, Hilkens J. Episialin, a carcinoma-associated mucin, is generated by a polymorphic gene encoding splice variants with alternative amino termini. J Biol Chem 1990;265:5573-8.  Back to cited text no. 5
    
6.
Gum JR, Byrd JC, Hicks JW, Toribara NW, Lamport DT, Kim YS, et al. Molecular cloning of human intestinal mucin cDNAs. Sequence analysis and evidence for genetic polymorphism. J Biol Chem 1989;264:6480-7.  Back to cited text no. 6
    
7.
Taylor CR. Standardization in immunohistochemistry: The role of antigen retrieval in molecular morphology. Biotech Histochem 2006;81:3-12.  Back to cited text no. 7
    
8.
Velcich A, Yang W, Heyer J, Fragale A, Nicholas C, Viani S, et al. Colorectal cancer in mice genetically deficient in the mucin muc2. Science 2002;295:1726-9.  Back to cited text no. 8
    
9.
Bu XD, Li N, Tian XQ, Li L, Wang JS, Yu XJ, et al. Altered expression of MUC2 and MUC5AC in progression of colorectal carcinoma. World J Gastroenterol 2010;16:4089-94.  Back to cited text no. 9
    
10.
Farhat MH, Barada KA, Tawil AN, Itani DM, Hatoum HA, Shamseddine AI, et al. Effect of mucin production on survival in colorectal cancer: A case-control study. World J Gastroenterol 2008;14:6981-5.  Back to cited text no. 10
    
11.
Voloshanenko O, Erdmann G, Dubash TD, Augustin I, Metzig M, Moffa G, et al. Wnt secretion is required to maintain high levels of Wnt activity in colon cancer cells. Nat Commun 2013;4:2610.  Back to cited text no. 11
    
12.
Ookawa K, Kudo T, Aizawa S, Saito H, Tsuchida S. Transcriptional activation of the MUC2 gene by p53. J Biol Chem 2002;277:48270-5.  Back to cited text no. 12
    
13.
Lugli A, Zlobec I, Baker K, Minoo P, Tornillo L, Terracciano L, et al. Prognostic significance of mucins in colorectal cancer with different DNA mismatch-repair status. J Clin Pathol 2007;60:534-9.  Back to cited text no. 13
    
14.
Kocer B, Soran A, Erdogan S, Karabeyoglu M, Yildirim O, Eroglu A, et al. Expression of MUC5AC in colorectal carcinoma and relationship with prognosis. Pathol Int 2002;52:470-7.  Back to cited text no. 14
    
15.
Walsh MD, Clendenning M, Williamson E, Pearson SA, Walters RJ, Nagler B, et al. Expression of MUC2, MUC5AC, MUC5B, and MUC6 mucins in colorectal cancers and their association with the cpG island methylator phenotype. Mod Pathol 2013;26:1642-56.  Back to cited text no. 15
    
16.
Betge J, Schneider NI, Harbaum L, Pollheimer MJ, Lindtner RA, Kornprat P, et al. MUC1, MUC2, MUC5AC, and MUC6 in colorectal cancer: Expression profiles and clinical significance. Virchows Arch 2016;469:255-65.  Back to cited text no. 16
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
   Abstract
  Introduction
   Materials and Me...
  Results
  Discussion
   References
   Article Figures
   Article Tables

 Article Access Statistics
    Viewed122    
    Printed5    
    Emailed0    
    PDF Downloaded22    
    Comments [Add]    

Recommend this journal