P21 and CEA expression and AgNOR counts in DMH induced colon carcinoma in rats

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P21 and CEA expression and AgNOR counts in DMH induced colon carcinoma in rats

AIM To study the expression of P21 and CEA, and AgNOR counts in various lesions of colonic mucosa and the mechanism of carcinogenesis. METHODS Thirty eight male Wistar rats were injected with DMH once a week, the experiment lasted 25 weeks. The expression of P21 and CEA was detected by the immunohistochemical methods and AgNOR was counted with silver staining in paraffin sections of various colonic lesions. RESULTS The incidence of colonic carcinoma in DMH treated rats was 71 05%(27/38), and lymphnode metastasis occurred in 6 rats. Immunohistochemical study showed that the expression of P21 was mainly in dysplasia and carcinomas, while CEA expressed in carcinoma and metastasis. The AgNOR counts was also increased in dysplasia and carcinomas. There were significant differences in P21 and CEA expression between benign and malignant lesions ( P <0 05). Difference in AgNOR counts was also significant between normal and dysplasia, dysplasia and malignant lesions ( P <0 05). CONCLUSION Dysplasia is a premalignant change of colonic carcinoma. The detection of P21 with immunohistochemistry and AgNOR counting might be important for screening colonic carcinoma and premalignant lesions clinically.