Our analysis of stromal changes between non-metastatic and metastatic canine mammary carcinomas highlighted molecular differences in the tumour microenvironment, including changes in VIT, TGFBR2, TGFBR3, LTBP4 and SFRP1 (Figs. 4 and 5). The gene discussed is SFRP1; the disease is neoplasm.