Flowchart depicting the study cohorts used for FISH analysis. (A) and IGHV-sequencing analysis (B) and the corresponding results. FFPE, formalin-fixed and paraffin-embedded; FF, fresh-frozen; I/II, FL at early clinical stage; III/IV, FL at advanced clinical stage; NANGS, newly acquired N-glycosylation sites; R, relapse; U, unknown clinical stage; TN, treatment-naive.