The 2003 study focused on the effect of Phenylbutyrate (PBA) and TSA on RA development, and they were observed to suppress TNF-α expression in affected tissues in the synovium while simultaneously promoting p21Cip1 and p16INK4 expression in cells of the synovial tissue during adjuvant arthritis, thus decreasing joint swelling and bone and cartilage degradation, among other symptoms being alleviated (Chung et al. 2003). The gene discussed is CDKN1A; the disease is rheumatoid arthritis.