ObjectiveTo study the expression and significance of proliferating cell nuclear antigen (PCNA) and argyrophilia nucleolar organizer regions (AgNORs) in colorectal carcinoma (CRC) and carcinoma adjacent mucosa (CAM).MethodsThe expression of PCNA in 48 cases of colorectal carcinoma tissue, CAM and 10 cases of normal mucosa was detected by immunohistochemistry techniques. AgNORs was determined with argyrophilia stain. ResultsThe PCNAlabeling index (PCNALI) and AgNORs count in CRC were higher than that in CAM and normal mucosa(P＜0.01).The PCNALI in Dukes C and D stage was higher than that in Dukes A(P＜0.05). The AgNORs count in 3 cmCAM was higher than 6 cmCAM (P＜0.01) and normal mucosa(P＜0.05). ConclusionSome cells proliferative activity were abnormal in CAM. It indicates that CAM is in an unstable premalignant state, which might have some correlation with the relapse of colorectal carcinoma.