A Comparative Study of the Detection of the p53 Abnormality in Breast Cancer by Using PCR-SSCP and Antibody Staining

ABSTRACT

BACKGROUND: Mutations eliminating or altering the p53 protein function are the single most common genetic alteration in nearly all types of human cancers. The project of the p53 gene is hypothesized to maintain genomic stability by blocking cell replication or by initiating apoptosis after DNA damage. Many p53 mutations alter the conformation of the protein, which results in abnormal overexpression. METHODS: This study investigated the correlation between p53 mutations detected at the DNA level and the p53 protein expression determined by immunohistochemical staining. Abnormalities of the p53 gene and protein in 30 primary paraffin embedded breast cancer tissues were examined. RESULTS: Mutations in p53 exons 5-8 were identified in 9 of the 30 cases (30%) by using a polymerase chain-reaction single stranded conformational polymorphism (PCR-SSCP) analysis. Overexpression of the p53 protein was detected in 11 of the 30 cases (37%) by using mouse monoclonal p53 antibody (Zymed Essence Co.) Positive immunohistochemical staining without mutations was detected by PCR-SSCP analysis in 4 cases, but a mutation with negative immunohistochemical staining was detected by PCR-SSCP analysis in only one case. p53 abnormality was not associated with TNM stages. The sensitivity between these methods was 73%. CONCLUSIONS: Positive immunohistochemical staining using p53 monoclonal antibody could detect p53 protein expression, but this result did not correlate completely with p53 mutation in exon 5-8.