Investigation of p27 tumor suppressor gene (CDKN1B) polymorphisms in dogs with malignant mammary tumors

Mammary tumors are the most common neoplasm in dogs, with a high mortality rate. The development of canine mammary tumors (CMT) is multifactorial, but different incidence rates between breeds suggest the effects of genetic risk factors. Many CMT-associated candidate genes were reported, mainly involved in cell cycle control. This study aims to investigate p27 tumor suppressor gene polymorphisms in dogs with mammary tumors and analyze the association between variations and CMTs. For this purpose, case and control groups were formed from 22 dogs diagnosed with malignant mammary tumors and 10 dogs with healthy mammary glands. The whole canine p27 gene was amplified and sequenced, including three exons, introns, and UTRs. Seven SNPs were identified in the 3'UTR of the p27 gene. The detected SNPs were as follows: A/C transversion at position 27:33916126, A/G transition at position 27:33915987, A/G transition at position 27:33915861, A/G transition at position 27:33915847, A/G transition at position 27:33915797, A/G transition at position 27:33915713, A/C transversion at position 27:33915684. No significant association was observed between these SNPs and canine mammary tumors. The coding region of the p27 gene of the dogs in this study was highly conserved and monomorphic. Further research on p27 polymorphisms and gene expression and their effects on mammary tumor development would shed light on the molecular basis of mammary cancers in dogs.