The correlation between PRL and autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and multiple sclerosis, has been confirmed, in which the excessive of PRL expression aggravates the symptoms of autoimmune diseases (Vera-Lastra and Jara, 2002; Borba et al., 2018; Borba and Shoenfeld, 2019). The gene discussed is PRL; the disease is rheumatoid arthritis.