Last but not least, the performance of hub genes exerts a great ability in discerning BD and HC (AUC ranging from 0.81-0.88) where CCL4 and NPY2R are proved as a moderate diagnostic biomarker in disease recognition from healthy subjects in our validation cohort (clinical characteristics are provided in the online Supplementary Material, Table S1). The gene discussed is NPY2R; the disease is Behcet disease.