library_construction_protocol: Blood samples of three pairs of matched patients with primary MIA and healthy individuals were collected.To ensure the quality of samples, the present study excluded those factors that could affect the state of peripheral blood, including pregnancy, chemotherapy and fever (≥37.3˚C). Individuals in the MIA and matched groups were matched based on age, sex and past medical history, such as hypertension and smoking. Total RNA was extracted from peripheral blood mononuclear cell samples using TRlzol reagent (Takara, USA) according to the kit's instructions. RNase R (Epicentre; Illumina, Inc.) was used to degrade linear RNA and enrich circRNAs in total RNA. The circRNA library was constructed according to the manufacturer's protocols (NEBNext Ultra Directional RNA Library Prep kit; New England BioLabs, Inc.). circRNA-Seq