Expression Of Aryl Hydrocarbon Receptor, CyclinD1 And P21 In Colon Cancer And Precancerous Lesions

Objective:To study the expressions of Aryl hydrocarbon receptor cyclinDl and P21 in colon cancer and precancerous leisions, and explore the potential role of AhR in development of colon cancer.Materials and methods:All two hundred specimens were obtained from the Department of Pathology of the First Affiliated Hospital of Nanchang University (Jan 2004-Jan 2009),including 24 cases of inflammatory polyps,30 cases of adenoma,27 cases of well-differentiated adenocarcinoma,30 cases of moderately-differentiated adenocarcinoma,30 cases of poorly-differentiated adenocarcinoma,29 cases of Non-lymph node metastasis and 30 cases of lymph node metastasis corresponding a complete information of pathological diagnosis and clinical condition.Normal colon specimens were collected from 30 healthy people.The expressions of AhR,cyclinDl and P21 were detected by immunohistochemistry and further analyzed by two pathologists.Results:1.The positive rate of AhR in colon cancer and precancerous lesions.AhR was expressed in nucleus and cytoplasm of cells.The percentage of positive cells was listed below:Normal colon group:23.3%(7/30);Inflammatory polyps group:25.0%(6/24);Adenomas group:30.0%(9/30);Colon cancer group:64.4%(94/146):Well-differentiated adenocarcinoma group:59.3%(16/27);Moderately-differentiated adenocarcinoma group:60.0%(18/30);Poorly-differentiated adenocarcinoma group:66.7%(20/30);Non-lymph node metastasis group:69.0%(20/29);Lymph node metastasis group:66.7%(20/30). There was a significant increase in the expression of AhR in colon cancer group compared with the groups of normal colon, inflammatory polyp and adenoma (P< 0.05).No difference was observed among the well-differentiated,moderately differen-tiated and poorly-differentiated colon cancer(P>0.05);The same phenomenon was showed between non-lymph node metastasis and lymph node metastasis group.2. cyclinDl positive rate in colon cancer and precancerous lesions. cyclinDl positive signal was located in the nucleus. cyclinDl nuclear expression positive rate:The expression of cyclinDl showed an increasing trend from the normal colon, inflammatory polyp, adenoma to colon cancer.Normal colon group:0%(0/30);Inflammatory polyps group:4.2%(1/24);Adenomas group:6.7%(2/30);Colon cancer group:53.4%(78/146).The cyclinDl expression in colon cancer group was higher than the non-cancer groups (P<0.05).Well-differentiated adenocarcinoma group:48.1%(13/27);Moderately-differentiated adenocarcinoma group:50.0%(l5/30);Poorly-differentiated adenocarcinoma group:60.0%(18/30).There was no significant difference among the above three groups(P> 0.05).Non-lymph node metastasis group:55.2%(16/29);Lymph node metastasis group:53.3%(16/30).There was no significant difference between the above two groups(P> 0.05).3.P21 positive rate in colon cancer and precancerous lesions.P21 positive signal was located in nucleus.P21 nuclear expression positive rate was analyzed as follows:P21 nuclear expression showed an increasing trend from the normal colon, inflammatory polyp, adenoma to colon cancer.Normal colon group:0%(0/30);Inflammatory polyps group:16.7%(4/24); Adenomas group:20.0%(6/30);Colon cancer group:74.0%(108/146).There was a significant increase in the expression of P21 between the colon cancer and the non-cancer group(P<0.05).Well-differentiated adenocarcinoma group:66.7%(18/27);Moderately-differentiated adenocarcinoma group:70.0%(21/30);Poorly-differentiated adenocarcinoma group:73.3%(22/30).There was no significant difference observed among the above three groups(P> 0.05).Non-lymph node metastasis group:79.3%(23/29);lymph node metastasis group:80.0%(24/30).There was no significant difference between them(P> 0.05).4.The relevance of the expression of AhR and cyclinDl in colon cancer and precancerous lesions.AhR and cyclinDl expressions in colon cancer and precancerous lesions are positively related (r=0.326, P=0.000).5. The correlation of AhR and P21 expression in colon cancer and precancerous lesions.The expressions of AhR and of P21 were positively correlated in colon cancer and precancerous lesions (r=0.288, P=0.000).Conclusion:The expressions of AhR, cyclinDl and P21 in normal tissue, inflammatory polyp,adenoma to colon cancer have gradually increased. The expression of AhR has significant correlation with cyclinD1 and P21 respectively. AhR,cyclinD1 and P21 are closely related to the progress of colon cancer,moreover,AhR may contribute to the development of colon cancer through cell cycle control.