[Detection of mutations in exon 7 of p53 from fresh tumor samples by single-strand conformation polymorphism and direct DNA sequencing].

OBJECTIVE

To detect mutations of exon 7 of p53 gene in laryngeal squamous cell carcinoma (LSCC) and analyze the relationship between the mutation and LSCC.

METHODS

Fresh tumor samples from 60 LSCC patients were examined using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct DNA sequencing.

RESULTS

An extra band in SSCP 3 was shown in 25 out of 60 samples. Exon 7 of p53 were detected by direct DNA sequencing in 8 samples taken at random from 25 cases. In 8 cases, 1 base pair deletion CCC-->CC in 250 codon which may result in frame shift mutation was shown. Simultaneously, in 3 cases, transversion AGT-->GGG in 261 codon which may bring out missense mutation was found. In 2 cases, 1 base pair deletion CGG-->GG in 248 codon was detected. In another case, 1 base pair deletion AGG-->AG in 249 codon was detected. Transversion ATC-->TTC in 254 codon was found in one of the cases. Transversion GGT-->TCA in 262 codon was found in another case.

CONCLUSION

The codon 248, 250, 261 may be "hot spots" in LSCC. Mutations and deletions in exon 7 of p53 gene occurred frequently in LSCC.