Conversely, the ICC still regards B-PLL as an entity but recommends its diagnosis only in cases without previous history of B-CLL (to exclude CLL progressing to B-PLL), negative for cyclin D1 and SOX11 (to exclude MCL), and lacking hairy surface projections and intrasinusoidal bone marrow (BM) infiltration (to exclude HCLv and splenic marginal zone lymphoma (SMZL)) (Fig. 1B). This evidence concerns the gene SOX11 and B-cell prolymphocytic leukemia.