Overall, ATG9B mRNA expression was decreased in nonerosive OLP patients compared with that in controls and erosive OLP patients (nonerosive OLP versus control: 0.56 ± 0.09 versus 1.71 ± 0.49, p = 0.044; nonerosive OLP versus erosive OLP: 0.56 ± 0.09 versus 1.34 ± 0.18, p = 0.001). The gene discussed is ATG9B; the disease is oral lichen planus.