Increased survival in dogs with malignant mammary tumours overexpressing HER-2 protein and detection of a silent single nucleotide polymorphism in the canine HER-2 gene.
The aims of this study were to explore the relationship between clinical outcome and HER-2 protein expression in dogs with malignant mammary tumours after surgery and to determine the sequence of the HER-2 gene. Tissues from 91 dogs diagnosed with malignant mammary tumours, six with benign lesions and two normal mammary glands were analysed for the expression of HER-2 by immunohistochemistry (IHC). Exons 14-18 of the HER-2 gene were amplified by reverse transcriptase polymerase chain reaction and sequenced in 19 tumours with IHC scores >2+; larger coding regions of HER-2 were analysed in five tumours. HER-2 protein overexpression was found in 27/91 (29.7%) of canine malignant mammary tumours. Dogs with HER-2-overexpressing malignant mammary tumours tended to have a higher survival rate than those that expressed a normal level of HER-2 within 2 years of surgery. In 3/19 cases, HER-2 sequences had a single nucleotide polymorphism, T(1725)C, with no change in the amino acid identity (Cys). No other sequence aberration of HER-2 was found.
Graduate Institute of Veterinary Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan.
Wei-Li
WL
Hsu
Hui-Min
HM
Huang
Jiunn-Wang
JW
Liao
Min-Liang
ML
Wong
Shih-Chieh
SC
Chang
D000818:Animals; D018076:DNA, Complementary / Q000032:analysis; D004283:Dog Diseases / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D004285:Dogs; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018734:Genes, erbB-2 / Q000235:genetics*; D007150:Immunohistochemistry / Q000662:veterinary; D053208:Kaplan-Meier Estimate; D015674:Mammary Neoplasms, Animal / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D020641:Polymorphism, Single Nucleotide; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016019:Survival Analysis
D018076:DNA, Complementary