The recognition of B-cell prolymphocytic leukemia (B-PLL) as a separate entity is controversial based on the current classification systems. Here, we analyzed the DNA methylome of a cohort of 20 B-PLL cases diagnosed according to the guidelines of the International Consensus Classification/Fourth revised edition of the World Health Organization Classification, and compared them with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), splenic marginal zone lymphoma (SMZL), and normal B-cell subpopulations. Unsupervised principal component analyses suggest that B-PLL is epigenetically distinct from CLL, MCL, and SMZL, which is further supported by robust differential methylation signatures in B-PLL.
View Article and Find Full Text PDFBruton tyrosine kinase (BTK) inhibitor therapy induces peripheral blood lymphocytosis in chronic lymphocytic leukemia (CLL), which lasts for several months. It remains unclear whether nongenetic adaptation mechanisms exist, allowing CLL cells' survival during BTK inhibitor-induced lymphocytosis and/or playing a role in therapy resistance. We show that in approximately 70% of CLL cases, ibrutinib treatment in vivo increases Akt activity above pretherapy levels within several weeks, leading to compensatory CLL cell survival and a more prominent lymphocytosis on therapy.
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