Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women,resulting in ovulation failure and other metabolic problems.However,the underlying mechanisms of it remain largely uncertain due to the complexity of clinical manifestations.PCOS is a systemic disorder involved endocrine,metabolism,immune system and many organs,and few studies have explored peripheral blood transcriptome in patients with PCOS.To this end,we performed gene expression profiling of peripheral blood from 8 PCOS patients and 8 healthy women with microarray.The significance analysis of microarray (SAM) software was employed to screen the differentially expressed genes (DEGs) and gene ontology (GO) was used for functional enrichment analysis.In total,181 DEGs with fold-changes >2.0 and q-values <0.05 were identified between the two groups.Among them,149 were up-regulated and 32 down-regulated in PCOS.Unsupervised clustering of expressed genes could readily differentiate PCOS from control.More importantly,inflammatory response pathway including 14 dysregulated genes was highly enriched in PCOS.Furthermore,10 randomly selected DEGs were validated using quantitative reverse-transcription PCR (qRT-PCR) assays.Our study provides further evidence of the role of systemic inflammatory response in the pathogenesis of this syndrome and it is likely translated into blood biomarkers and helpful interventions in clinical practice.