Abstract: Objective The objective of this study was to explore the differential expression of circular RNAs(circRNAs)in multiple myeloma(MM)and predict their biological function. Methods Bone marrow samples of five MM patients who visited the department of hematology, Peking University Third Hospital from January to February 2023 and three healthy volunteers during the same period were collected for transcriptome sequencing to determine the differentially expressed circRNAs in MM. The miRNAs binding sites of circRNAs were predicted. GO and KEGG enrichment analyses were performed on differential circRNAs. The real-time fluorescence quantitative PCR(qRT-PCR)was used to verify some circRNAs. Results A total of 926 differentially expressed circRNAs were found in MM and normal control bone marrow samples, of which 818 were up-regulated and 108 were down-regulated. These differentially circRNAs had a large number of miRNA binding sites, such as miR-619-5p, miR-17-5p, miR-20a-5p, et al. GO analysis showed that these differential circRNAs were mainly involved in biological metabolism processes such as cell protein metabolism, organic matter metabolism, and nitrogen-containing compound metabolism. KEGG analysis showed that signal pathways such as Rap1, FoxO, and AMPK were significantly enriched. The 4 circRNAs whose expression was significantly up-regulated were verified through qRT-PCR experiments, and it was found that circ_0004524 and circ_0003823 were significantly up-regulated, consistent with sequencing results. Conclusion MM patients have unique circRNAs expression profiles, and studies in-depth functional and mechanism will help provide potential molecular markers for the diagnosis and treatment of MM.

Key words: Multiple myeloma, circular RNA, Bioinformatics analysis, Signal pathway