Abstract: Objective:In this study we aimed to identify the AIM2 expression in colorectal tissues and relationship between AIM2 expression and clinic pathological parameters.Methods:Paired samples of CRC tissues and corresponding noncancerous colonic tissues from 64 CRC patients taken from surgical excision specimen were included in this study.The expression of AIM2 was analyzed by quantitative realtime PCR assay(qRTPCR).We used immunohistochemical staining assay to evaluate the expression of AIM2 in protein level in 68 pairs of colorectal specimen,and we analyzed the relationship between AIM2 expression and clinic pathological parameters.Result:The result of qRTPCR suggested that the expression of AIM2 was significantly decreased in colorectal cancer tissues compared with the corresponding noncancerous colonic tissues(P<0.01).The immunoreactivity score and positive rate of colorectal cancer tissues was also significantly lower than corresponding noncancerous colonic tissues.The of colorectal cancer tissues was associated with the tumor grade of colorectal cancer.The immunoreactivity score is decreased in the one which tumor grade was lower.Conclusion:The expression of AIM2 was significantly decreased in colorectal cancer tissues,and the AIM2 expression was associated with the tumor grade of colorectal cancer.

Key words: absent in melanoma 2, colorectal cancer；tumor grade