Significantly lower expression (p < 0.01) of ghrelin antigen was detected in cell line isolated from primary canine mammary adenocarcinoma (CMT-W1) than in the cell line isolated from its metastasis to the lungs (CMT-W1M) (5030 ± 428.4 and 7494 ± 548.3, respectively). Here, GHRL is linked to breast adenocarcinoma.