Identification of deletions and insertions in the p53 gene using multiplex PCR and high-resolution fragment analysis: application to breast and ovarian tumors.

We have developed a simple and highly efficient method to detect deletions and insertions in the p53 gene. All 11 exons of the p53 gene were amplified along with a control sequence in four multiplex PCR reactions in the presence of fluorescein-labeled primers. The PCR products were resolved on an automated sequencing gel and the DNA fragments were detected by fluorescence. Using this method, we screened 7 DNA specimens from ovarian tumors, 19 from breast tumors, and 26 from normal breast tissues. No abnormality was found in any of the DNA samples extracted from the normal tissues. A 19 base pair deletion in exon 5 of the p53 gene was detected in one ovarian tumor. Insertions were identified in two breast and two ovarian tumors. The insertions were identical in 3 of these tumors and consisted of a 16 bp repeat within intron 3 of the p53 gene. It appears that the insertion within intron 3 may represent a hot spot for duplication of the normal sequence at that site.