title: Topographic expression of p21WAF1/SDI1/CIP1, bcl2, and p53 is altered at the early stage of colorectal carcinogenesis.
abstract: We analyzed the expression of p21, bcl2, and p53 in normal and different pathologic mucosa of the human colorectum using immunohistochemistry and cold polymerase chain reaction-single strand conformation polymorphism. The topography of normal mucosa showed; bcl2 and p53 expression restricted to basal epithelial cells and p21 expressed only in superficial epithelial cells. This topographic expression was altered in hyperplastic polyps and adenomas. Hyperplastic polyps revealed absence of or weak bcl2 expression and strong p21 expression without topography. In adenomas, whereas bcl2 expression increased and extended to parabasal and superficial dysplastic epithelium, the increase of p21 expression was limited to surface dysplastic epithelium. p53 was weakly expressed throughout the full thickness of dysplastic epithelium. Bcl2 expression in adenomas was stronger than in carcinomas; p53 expression was converse and p21 expression was variable. In carcinomas, this topographic expression was largely abrogated but p53 mutation (36%) was more frequent than in adenomas (2%). In carcinomas, p21 and p53 expression correlated inversely, but there was no relationship with bcl2. These results suggest that there is precisely ordered topographic pattern of p21, bcl2, and wild p53 expression in normal colorectal cells, but this becomes disordered during the early stage of colorectal carcinogenesis.
authors.affiliation: Molecular Pathology, University of Texas, MD Anderson Cancer Center, Houston 77030, USA. jhcho@notes.mdacc.tmc.edu
authors.forename: J H
authors.initials: JH
authors.lastname: Cho
authors.forename: I H
authors.initials: IH
authors.lastname: Roe
authors.forename: C Y
authors.initials: CY
authors.lastname: Lim
authors.forename: D K
authors.initials: DK
authors.lastname: Park
authors.forename: W H
authors.initials: WH
authors.lastname: Kim
authors.forename: Y I
authors.initials: YI
authors.lastname: Kim
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis*; D006801:Humans; D016296:Mutagenesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53