[Detection of point mutation of p53 gene by non-isotopic PCR-SSCP in paraffin-embedded breast cancer tissue].

Non-isotopic PCR-SSCP method was used to detect point mutation of p53 gene in paraffin-embedded breast cancers. The abnormal shifting of the single-stranded DNA (ssDNA) was identified in 14 out of 60 cases. The point mutations of four cases were found in exons 5-6, three in exon 7 and seven in exon 8. The mutant p53 protein was detected by immunohistochemistry. The positive nuclear staining was observed in 13 cases, among which 11 cases showed abnormal shifting of ssDNA in SSCP analysis. The point mutations of the other two cases might occur in the regions which were not examined in this study. The point mutations of p53 were found in 5 cases in the absence of detectable protein. This probably resulted from the reduction or loss of antigenicity of p53 in some of the routinely processed tissues. Our results indicate that detection of point mutations of p53 gene by PCR-SSCP method is more accurate and reliable than that by immunohistochemistry and non-isotopic PCR-SSCP is especially useful in the screening of point mutations during handling a large number of samples.