Novel canine tumour suppressor gene p53 mutations in cases of skin and mammary neoplasms

Exons 4 to 8 of the tumour suppressor gene p53 were analysed in 25 skin and 25 mammary tumours of 50 dogs. A 1 bp deletion (ACC --> AC) was detected i n codon 89 in exon 4 in a squamous cell carcinoma. A missense mutation CGC --> CAC (arginine --> histidine) was present in codon 162 in exon 5 in a ma mmary adenocarcinoma. Moreover, a silent mutation occurred in codon 103 (se rine) of exon 4 in a mammary adenoma. The somatic nature of the three mutat ions was demonstrated.