SF3B1 expression and methylation in normal and CLL cells. (A) SF3B1 relative expression in different human tissues. (B) SF3B1 relative expression in normal B-cell subpopulations and CLL samples. CB, centroblast; CC, centrocyte. Data generated from Affymetrix HG-U133Plus2 arrays. (C) DNA methylation on SF3B1 in CLL samples with or without SF3B1 mutation and normal B cells. (D) Targeted pyrosequencing of a SF3B1 K700E site of cDNA from normal peripheral blood mononuclear cells (top, NL PBMC) compared with cDNA from a CLL sample with known K700E mutation in SF3B1 (bottom). K700E mutation is generated from an A2098G transition on the sense strand; this pyrosequencing assay was designed to detect the T to C transition at the corresponding site on the antisense strand. cDNA, complementary DNA. Panel A adapted from the Novartis Gene Atlas¹⁶  with permission. Panel B adapted from Rossi et al³  with permission. Panel C adapted from Kulis et al¹⁷  with permission.