BCL2 and B-cell chronic lymphocytic leukemia: Immunohistochemical assessment of 8 CLL and 4 RS biopsies, including 3 matched CLL-RS samples, showed an unexpectedly higher expression of PUMA in RS compared to CLL (Supplementary Fig. 5C), suggesting that CLL cases acquiring resistance to BCL-2 antagonism [27] and those transforming into RS might modulate PUMA in an opposite manner.