Arid5a actually binds to the promoter of the Col2a1 gene and enhances transcription of Col2a1, which further induces acetylation of histone 3 proteins to regulate chondrocyte differentiation in association with Sox9. Recently, we observed that Arid5a regulates the invasion and metastasis of breast cancer cells (20). The gene discussed is COL2A1; the disease is breast carcinoma.