Objective To investigate the expression of protein interacting with Cα kinase 1 (PICK1) and its significance in colorectal adenocarcinoma.Methods The expression of PICK1 were detected by immunohistochemistry and Western blot methods in tissues of colorectal adenocarcinoma,colorectal adenoma,colorectal polyp and adjacent tissues.The correlation between PICK1 and clinical pathological data was explored.Results Immunohistochemical assay showed that the positive ratio of PICK1 protein was 72.5 ％ (74/102),and overexpressed in 31 cases (30.4 ％,31/102) with colorectal adenocarcinoma.The ratio of high expression level of PICK1 in colorectal adenoma tissues (22.2 ％,8/36) was significantly higher than that in the adjacent tissues (0,0/40) (P ＜ 0.05).The ratio of high expression level of PICK1 in colorectal polyp tissues (5.6 ％,2/36) was no statistically difference compared with that of the adjacent tissues (P ＞ 0.05).Western blot analysis revealed that the expression of PICK1 in colorectal adenocarcinoma (1.10±0.04) was significantly higher than that in the adjacent tissues (0.75±0.07) (P ＜ 0.05).The result showed significant correlation with the tumor location,the degree of differentiation,depth of invasion,TNM stages and lymph metastasis (all P ＜ 0.05).However,there is no correlation was revealed between PICK1 expression and the patients age,gender (both P ＞ 0.05).Conclusion The expression of PICK1 may be associated with the tumorgenesis,progression,invasion and metastasis of colorectal adenocarcinoma,which contributes to the prognosis of patients.