Immunohistochemical expression of p16, p53, and p63 in colorectal adenomas and adenocarcinomas.
OBJECTIVE
The aim of this study was to investigate the immunohistochemical expression of p16, p53, and p63 proteins according to some pathologic parameters related to colorectal adenomas and adenocarcinomas such as grade of dysplasia and histologic type.


METHODS
Immunohistochemistry with the antibodies p16, p53, and p63 was performed in tubular, tubular-villous, and villous adenomas (n = 30) and in well, moderately, and poorly differentiated adenocarcinomas (n = 30). The p63-positive cases were submitted to double immunolabeling with the cytokeratin 5 (CK5).


RESULTS
The p16 and p53 labelings were observed in some adenomas and adenocarcinomas but without any association with p63 expression, histologic type, or grade of differentiation of the neoplasm. P63 expression was found mainly in the villous adenomas and in the poorly differentiated adenocarcinomas. The poorly differentiated adenocarcinomas also exhibited coexpression of CK5 and p63.


CONCLUSIONS
Despite both p16 and p53 having been detected in colorectal neoplasms, they were not related to the different histologic variables nor to the expression of p63. However, p63 expression was closely associated with villous adenomas and poorly differentiated adenocarcinomas. Thus, p63 may represent a marker of poor differentiation in colorectal neoplasms. The coexpression of p63 and CK5 observed in this study could be related to divergent differentiation during the development of colorectal cancer, although further studies are warranted to refine the understanding of this process.
Department of Pathology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Fabiana Pirani
FP
Carneiro
Leandra Náira Zambelli
LN
Ramalho
Sérgio
S
Britto-Garcia
Alfredo
A
Ribeiro-Silva
Sérgio
S
Zucoloto
D000230:Adenocarcinoma; D000236:Adenoma; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D004268:DNA-Binding Proteins; D016147:Genes, Tumor Suppressor; D019942:Genes, p16; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins
D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; C115051:TP63 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D007633:Keratins