Besides, in RA synovial tissue, PRL and PRL‐like polypeptides could participate in a bidirectional communication between immunocytes and fibroblasts and might act via proto‐oncogenes and transcriptional factors, leading to cell proliferation, that is, neo‐angiogenesis, and the production of catabolic enzymes such as MMPs and cathepsins.47 Here, PRL is linked to rheumatoid arthritis.