Chronic lymphocytic leukemia (CLL), the most frequently occurring leukemia in western countries, is a heterogeneous disease and characterized by the accumulation of monoclonal B lymphocytes in blood, bone marrow, and lymphoid tissues [1]. Although diagnosis and therapy have been developing, several high-risk features for CLL patients have been identified [2]. Immunoglobulin heavy-chain variable region (IGHV) has been confirmed as a valuable independent prognostic factor [3]. However, it is of vital importance to explore alternative markers because of limitation of the detection of IGHV mutation in routine laboratory diagnosis process.

Recently, accumulating evidence reveals that non-coding RNAs including circRNAs may exert vital biological functions and can be used as new biomarkers for diagnosis as well as provide promising therapeutic approaches for various solid tumors [4, 5] and leukemias [6, 7]. CircRNAs which are characterized by covalently closed continuous loops without 5′ to 3′ polarity and polyadenylated tail were proved to function as competing endogenous RNAs to interact with microRNAs (miRNAs) and regulate targeted genes expression [8, 9]. However, little is known about the roles of circRNAs in CLL.