AFF3 and acute lymphoblastic leukemia: Following these criteria, ten of the circRNAs with validated upregulation in B-cells, T-cells or in both lymphocyte populations (Fig. 2d) were selected for quantification in BCP-ALL, including circRNAs from known genes (AFF2, AFF3, BCL2, FBXW7, IKZF1, IL4R, PAX5, SETBP1 and ZCCHC7) and the newly identified circX(intergenic) highly expressed in lymphocytes.