الفهرس 
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Abstract
Colorectal cancer is a major cause of morbidity and mortality throughout the world. It accounts for over 9% of all cancer incidence. It is the third most commonly diagnosed cancer in males and the second in females. Various pathological conditions like inflammatory bowel diseases especially ulcerative colitis and adenomatous polyps predispose to CRC development.
MUC2 is the major secretory mucin synthesized and secreted by goblet cells, whereas goblet and absorptive cells express membrane-bound mucins such as MUC1 in the apical membrane. Deregulation of mucin production in the intestinal tract, contributes to chronic inflammation and tumorigenesis.
The aim of this work is to determine the cellular location of MUC 1 and MUC2 in specimens of normal, inflammed and neoplastic lesions of the colon to determine the potential applicability of MUC1 and MUC2 expression as a predictor of malignant transformation of colorectal mucosa.
In the present study, correlation was done between MUC1 and MUC2 expression in colorectal cancer and different clinicopathologic parameters ( histological type, grade, site and stage ).
The present work included seventy cases of colonic specimens received at the Pathology Department, Medical Research Institute, Alexandria University in the period between the January 2014 and January 2015.
The cases studied were divided into four groups: I :10 control colorectal specimens, II : 15 specimens of ulcerative colitis, III : 15 specimens of colorectal adenoma and IV: 30 specimens of colorectal carcinoma.
Histological examination as well as immunohistochemical study with MUC1 and MUC2 were done.
According to the results of the present study, the control colonic specimens showed negative MUC1 expression while MUC2 was positive in all control specimens.
In UC, MUC 1 was detected in 6 of 15 cases (40%), whereas MUC 2 expression was detected in all 15 cases.
In colorectal adenomas, MUC 1 immunoreactivity was found in 5of 15 cases (33.3%), while MUC 2 positivity was observed in 14 of 15 cases (93.3%). The five MUC 1 positive cases were adenoma with high grade dysplasia while the remaining 10 MUC 1 negative cases were adenoma with low grade dysplasia.
Among the 30 cases of colorectal carcinomas, MUC1 was positive in 23 cases (76.7%) while MUC2 was positive in 18 cases (60%).
The results of the present study demonstrated that the expression of MUC1 was significantly higher in carcinomas, as compared with UC cases and adenomas (p1=0.015, p2=0.004). On the other hand, MUC2 expression was significantly lower in carcinomas, as compared with UC cases and adenomas. (p1=0.004, p2=0.02).
In the present study, correlation was done between MUC1 and MUC2 expression in colorectal cancer and different clinicopathologic parameters.
As regard histological type of colorectal cancer, MUC1 expression was significantly higher in conventional adenocarcinoma than mucinous carcinoma (p=0.001). MUC2, on the other hand, showed a statistically significant inverse pattern characterized by more expression in mucinous carcinoma than in conventional adenocarcinoma. (p=0.003).
Regarding histological grade of conventional adenocarcinoma, the present study showed that there is no significant correlation between the expression of MUC1 or MUC2 and histological grade in conventional adenocarcinoma (p-values= 0.619 and 0.748, respectively).
The present study showed that, there was high significant association between advanced tumor stage and MUC1 expression (p=0.003). On the other hand, MUC2 showed a statistically significant inverse pattern characterized by more expression in stage I and stage II than in stage III (p=0.01).
This study demonstrated an insignificant association between MUC1 or MUC2 expression and the location of the tumor in the large bowel (p-values 0.226 and 0.748, respectively).