Canine Mammary Tumors as a Potential Model for Human Breast Cancer in Comparative Oncology

Table 4

Analyses of predictor variables in relation to canine mammary tumors expressing differentially Cox2 protein.

Variable	Cox2 protein expression (mean ± SD)				value (among groups)
	Negative	Weak	Moderate	Strong
Tumor size (cm)	2.28 ± 1.31	2.9 ± 1.38	3.35 ± 1.44	4.8 ± 1.25	<0.001
Ki67 expression	8.11 ± 6.17	14.8 ± 11.98	23.86 ± 9.02	31.55 ± 6.17	<0.001
Vet-NPI	2.26 ± 1.19	3.11 ± 1.48	3.38 ± 1.29	5.29 ± 0.82	<0.001

One-way ANOVA was applied to compute the values among 64 canine mammary tumors that differentially express Cox2 protein. All variables displayed significant differences (), so that triple-negative tumors showed the highest mean compared with other subgroups. Veterinary Nottingham Prognostic Index (Vet-NPI) was computed as: Vet-NPI = [tumor size (cm) × 0.2] + histological grade (1, 2 or 3) + evidence of vascular invasion and/or regional lymph node metastases (1 or 2 if absent or present, respectively). SD, standard deviation.