Comparison of p53 gene mutation and protein overexpression in colorectal carcinomas.
Immunocytochemistry (ICC) has been used routinely to stain for p53 overexpression in a range of human tumours. The underlying assumption has been that positive staining indicates a mutation in the p53 coding sequence. Recently, however, discordancy has been observed and the accuracy of ICC as a marker of p53 gene mutation has been questioned. In this study of 109 colorectal adenocarcinomas, we compared ICC staining with p53 gene mutations detected by single-strand conformation polymorphism (SSCP) analysis. Concordancy between the two techniques was found in 69% of tumours. ICC-positive/SSCP-negative cases accounted for 20% of tumours and ICC-negative/SSCP-positive cases for the remaining 11%. These results caution against the assumption that p53 protein overexpression is always associated with a gene mutation. Epigenetic phenomena may account for a significant proportion of ICC-positive tumours.
Dix
B
B
University Department of Surgery, Sir Charles Gairdner Hospital, Nedlands, Western Australia.
Robbins
P
P
Carrello
S
S
House
A
A
Iacopetta
B
B
D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D015870:Gene Expression; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009154:Mutation; D018807:Polymorphism, Single-Stranded Conformational; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*
D000911:Antibodies, Monoclonal; D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53