Exposure to human recombinant RLN2 for 24 h induced S100A4 expression and increased cell migration in ERα-negative MDA-MB-231 triple-negative breast cancer cells, but exposure for more than 3 days downregulated S100A4 levels and reduced cell migration and invasiveness in the same cell model in an RXFP1-dependent manner, leading to reduced tumor xenograft growth in vivo (12). Here, S100A4 is linked to triple-negative breast carcinoma.