Amplification of the cyclin A gene in canine and feline mammary tumors

DNAs from 33 canine mammary tumors and 8 feline mammary carcinomas were examined by Southern blot analysis to clarify genomic abnormalities of the cyclin A gene. Amplification of cyclin A was detected in 27.3% (9/33) of canine mammary tumors and 87.5% (7/8) of feline mammary carcinomas. It was suggested that amplification of cyclin A do not correlate directly with the tumorigenesis of canine mammary tumors, because there was no significant difference of incidence of cyclin A amplification between the benign and malignant tumors. In feline mammary carcinomas, the high frequency of cyclin A amplification raised the possibility that the amplification lead to the protein overexpression and play an important role in the tumorigenesis.