Mutational analysis of p53 tumour suppressor gene in canine mammary tumours using PCR-SSCP and sequencing

摘要

The present study was conducted to investigate the role of p53 rumour suppressor gene in canine mammary tumours, for which exons 5 and 7 were screened for detection of mutations by PCR-single strand conformational polymorphism (PCR-SSCP) and direct sequencing in 15 mammary tumour tissues. PCR-SSCP revealed aberrantly migrating bands suggestive of mutations in amplified exon 5 (codon 117-175) of p53 tumour suppressor gene in 3 (20%) spontaneous canine mammary tumour cases. By direct sequencing method,all three cases of mammary tumour showed mutations. In one case of mammary adenocarcinoma, mutant bands revealed four mutations; two silent mutations on codon No. 117 (CTC->CTT) and 137 (CCA->CCG) as well as two missense mutations on codon 157 (ACC->ACA) and codon 158 (GAG->AAG). Screening of amplified exon 5 (from codon 165) to exon 7 (upto codon 241) of p53 gene segment by PCR-SSCP revealed similar band pattern for all the 15 samples, suggesting absence of mutations. The study indicated that mutations in p53 gene might be invariably involved in canine mammary neoplastic conditions and needs to screen large number of cancers to explore ifs role.