Studies On The Carcinogenetic Potentials Of Colorectal Serrated Adenoma

BackgroundColorectal serrated adenoma (SA)has been proposed by WHO as a new colorectal adenoma since 2000,and researchers on SA became hotpoint. SA might be related to sproadic colorectal cancer with microsatellite instability (MSI).Most of the researchers focused on the critieoria of pathological diagnosis and biological carcinogenesis of SA.However, less attention was paid to the comparison between SA and CRC/tublar adenoma(TA)/villioustublar adenoma(VTA) in terms of pathological and biological findings.ObjectiveTo analyse and compare the expression ofβ-catenin protein, P53 and Ki67 between SA andTA,VTA,CRC; for those with positive P-catenin, P-catenin exon3 mutation will be checked in order to clarify the genetic defect. Cases with both SA and TA/VTA will be analyzed based on clinical and pathological features and to compare the similarity and difference.Methods1.To analyse P-catenin protein, P53, Ki67 immunohistochemical staining of 30 cases SA,28 cases TA,2lcases VTA and 21 cases CRC;and the SA/TA which come from the same cases.2.DNA extracting from the tissues which have abnormal expression ofβ-catenin,using PCR testing their exon3 mutation.Results1.P53:no significant difference was found between SA,TA and VTA, significant difference was found in SA and CRC,the positive percentage of SA was lower than CRC(P<0.05); Ki67:there was no significant difference among the four lesions(P>0.05);β-catenin:no significant difference was found between SA and TA, the positive percentage of SA was lower than VTA and CRC(P<0.05).2.There was no one case found had mutation ofβ-catenin exon 3 among 8 cases SA,6 cases TA,5 cases VTA and 10 cases CRC.3.No significant difference was found in terms of location, diameter and the degree of dysplasia. However, sessile type of adenoma in SA was more than that in TA (P<0.05); there was no significant difference was noticed in terms of P-catenin protein, P53 and Ki67 expression (P>0.05).Conclusion1.The P-catenin protein, P53, Ki67 immunohistochemical staining indicate that:SA is a kind of proliferative adenoma,its carcinogenetic potentials was lower than VTA,no significant difference was found between the SA and TA.2.The P-catenin exon3 is not the reason of its abnormal expression,there maybe has another factor which result in its abnormal expression.3.The small sample self-match study showed that the sessile type of SA is more than that of TA, no other significant difference was found between the SA and TA in terms of some clinical/pathological characteristics and immunohistochemical findings.