Data from: Canine mammary tumours are affected by frequent copy number aberrations, including amplification of MYC and loss of PTEN

Background: Copy number aberrations frequently occur during the
development of many cancers. Such events affect dosage of involved genes
and may cause further genomic instability and progression of cancer. In
this survey, canine SNP microarrays were used to study 117 canine mammary
tumours from 69 dogs. Results: We found a high occurrence of copy number
aberrations in canine mammary tumours, losses being more frequent than
gains. Increased frequency of aberrations and loss of heterozygosity were
positively correlated with increased malignancy in terms of
histopathological diagnosis. One of the most highly recurrently amplified
regions harbored the MYC gene. PTEN was located to a frequently lost
region and also homozygously deleted in five tumours. Thus, deregulation
of these genes due to copy number aberrations appears to be an important
event in canine mammary tumour development. Other potential contributors
to canine mammary tumour pathogenesis are COL9A3, INPP5A, CYP2E1 and RB1.
The present study also shows that a more detailed analysis of chromosomal
aberrations associated with histopathological parameters may aid in
identifying specific genes associated with canine mammary tumour
progression. Conclusions: The high frequency of copy number aberrations is
a prominent feature of canine mammary tumours as seen in other canine and
human cancers. Our findings share several features with corresponding
studies in human breast tumours and strengthen the dog as a suitable model
organism for this disease.