Ghrelin and growth hormone secretagogue receptor expression at mRNA level in canine mammary adenocarcinomas. The relative gene expression level (ratio) of (A) ghrelin and (B) growth hormone secretagogue receptor in adenocarcinomas of the 1st, the 2nd, the 3rd grade of malignancy (total n = 18) determined using Real-time PCR. The result are presented as a mean (±SEM) from 6 tumors in each group. The statistical analysis was performed using Prism version 5.00 software (GraphPad Software, USA). The one-way ANOVA and Tukey HSD post-hoc test were applied. p < 0.05 was regarded as significant and marked as *.