To further evaluate the impact of ERAP1 expression on DSS-induced colitis and sulfasalazine treatment in ERAP1 WT and ERAP1+/− mice, three genes (Anxa9, Atp2a1, and Hepacam2) were selected from the RNA-seq data and validated using RT-qPCR in spleen tissue. The gene discussed is ANXA9; the disease is colitis.