Key Points• Long-term remissions after FCR chemoimmunotherapy in previously untreated patients with CLL.• Updated results on safety and efficacy of the CLL8 trial.Despite promising results with targeted drugs, chemoimmunotherapy with fludarabine, cyclophosphamide (FC), and rituximab (R) remains the standard therapy for fit patients with untreated chronic lymphocytic leukemia (CLL). Herein, we present the long-term follow-up of the randomized CLL8 trial reporting safety and efficacy of FC and FCR treatment of 817 treatment-naïve patients with CLL. The primary end point was progressionfree survival (PFS). With a median follow-up of 5.9 years, median PFS were 56.8 and 32.9 months for the FCR and FC group (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.50-0.69, P < .001). Median overall survival (OS) was not reached for the FCR group and was 86.0 months for the FC group (HR, 0.68; 95% CI, 0.54-0.89, P 5 .001). In patients with mutated IGHV (IGHV MUT), FCR improved PFS and OS compared with FC (PFS: HR, 0.47; 95% CI, 0.33-0.68, P < .001; OS: HR, 0.62; 95% CI, 0.34-1.11, P 5 .1). This improvement remained applicable for all cytogenetic subgroups other than del(17p). Long-term safety analyses showed that FCR had a higher rate of prolonged neutropenia during the first year after treatment (16.6% vs 8.8%; P 5 .007). Secondary malignancies including Richter's transformation occurred in 13.1% in the FCR group and in 17.4% in the FC group (P 5 .1). First-line chemoimmunotherapy with FCR induces long-term remissions and highly relevant improvement in OS in specific genetic subgroups of fit patients with CLL, in particular those with IGHV MUT. This trial was registered at www.clinicaltrials.gov as #NCT00281918. (Blood. 2016;127(2):208-215)

Key Points We identify gain-of-function mutations involving IL2RG, JAK1/3, and STAT5B as well as deleterious mutations affecting EZH2, FBXW10, and CHEK2 in T-PLL. Pharmacologic targeting of primary T-PLL cells with the STAT5 inhibitor pimozide leads to apoptosis.

T-cell prolymphocytic leukemia (T-PLL) is a rare and poor-prognostic mature T-cell malignancy. Here we integrated large-scale profiling data of alterations in gene expression, allelic copy number (CN), and nucleotide sequences in 111 well-characterized patients. Besides prominent signatures of T-cell activation and prevalent clonal variants, we also identify novel hot-spots for CN variability, fusion molecules, alternative transcripts, and progression-associated dynamics. The overall lesional spectrum of T-PLL is mainly annotated to axes of DNA damage responses, T-cell receptor/cytokine signaling, and histone modulation. We formulate a multi-dimensional model of T-PLL pathogenesis centered around a unique combination of TCL1 overexpression with damaging ATM aberrations as initiating core lesions. The effects imposed by TCL1 cooperate with compromised ATM toward a leukemogenic phenotype of impaired DNA damage processing. Dysfunctional ATM appears inefficient in alleviating elevated redox burdens and telomere attrition and in evoking a p53-dependent apoptotic response to genotoxic insults. As non-genotoxic strategies, synergistic combinations of p53 reactivators and deacetylase inhibitors reinstate such cell death execution.

As new generations of targeted therapies emerge and tumor genome sequencing discovers increasingly comprehensive mutation repertoires, the functional relationships of mutations to tumor phenotypes remain largely unknown. Here, we measured ex vivo sensitivity of 246 blood cancers to 63 drugs alongside genome, transcriptome, and DNA methylome analysis to understand determinants of drug response. We assembled a primary blood cancer cell encyclopedia data set that revealed disease-specific sensitivities for each cancer. Within chronic lymphocytic leukemia (CLL), responses to 62% of drugs were associated with 2 or more mutations, and linked the B cell receptor (BCR) pathway to trisomy 12, an important driver of CLL. Based on drug responses, the disease could be organized into phenotypic subgroups characterized by exploitable dependencies on BCR, mTOR, or MEK signaling and associated with mutations, gene expression, and DNA methylation. Fourteen percent of CLLs were driven by mTOR signaling in a non–BCR-dependent manner. Multivariate modeling revealed immunoglobulin heavy chain variable gene (IGHV) mutation status and trisomy 12 as the most important modulators of response to kinase inhibitors in CLL. Ex vivo drug responses were associated with outcome. This study overcomes the perception that most mutations do not influence drug response of cancer, and points to an updated approach to understanding tumor biology, with implications for biomarker discovery and cancer care.

Key Points• Exosomal NKp30-ligand BAG6 is crucial for detection of tumor cells by NK cells in vitro and in vivo.• Soluble plasma factors including BAG6 suppress NK cell cytotoxicity and promote evasion of CLL cells from NK cell anti-tumor activity.Natural killer (NK) cells are a major component of the anti-tumor immune response. NK cell dysfunctions have been reported in various hematologic malignancies, including chronic lymphocytic leukemia (CLL). Here we investigated the role of tumor cellreleased soluble and exosomal ligands for NK cell receptors that modulate NK cell activity. Soluble CLL plasma factors suppressed NK cell cytotoxicity and downregulated the surface receptors CD16 and CD56 on NK cells of healthy donors. The inhibition of NK cell cytotoxicity was attributed to the soluble ligand BAG6/BAT3 that engages the activating receptor NKp30 expressed on NK cells. Soluble BAG6 was detectable in the plasma of CLL patients, with the highest levels at the advanced disease stages. In contrast, NK cells were activated when BAG6 was presented on the surface of exosomes. The latter form was induced in non-CLL cells by cellular stress via an nSmase2-dependent pathway. Such cells were eliminated by lymphocytes in a xenograft tumor model in vivo. Here, exosomal BAG6 was essential for tumor cell killing because BAG6-deficient cells evaded immune detection. Taken together, the findings show that the dysregulated balance of exosomal vs soluble BAG6 expression may cause immune evasion of CLL cells. (Blood. 2013;121(18):3658-3665) IntroductionChronic lymphocytic leukemia (CLL) patients suffer from severe immune defects resulting in increased susceptibility to infections and failure to generate an anti-tumor immune response. 1 Natural killer (NK) cells, lymphocytes of the innate immune system, are considered to be a major component of the immunosurveillance in leukemia. [2][3][4] However, little is known about the functionality of NK cells and their role in tumor immune escape in CLL.NK cells are tightly regulated by inhibitory or activating "missing self" and "induced self" signals sensed via cell surface receptors. 5 The best examined activating receptors are the Fc receptor CD16, NKG2D, and the natural cytotoxicity receptors (NCRs) NKp30, NKp44, and NKp46. Known ligands for NKG2D are the major histocompatibility complex (MHC) class I-related molecules MICA/B and the UL16-binding proteins (ULBP1, ULBP2, ULBP3, ULBP4, ULBP5, and ULBP6) that are induced upon cellular stress on target cells. 6,7 Only a few ligands for the NCRs have been identified to date. [8][9][10][11][12][13][14] Surprisingly, among novel ligands for NKp30 (BAG6 [BAT3], 10 B7-H6 11 ), NKp44 (proliferating cell nuclear antigen 12 ) and NKp46 (vimentin 13,14 ), only B7-H6 is a surface membrane ligand. BAG6, proliferating cell nuclear antigen, and vimentin are proteins without any classical transmembrane domain and are known to exert divergent intracellular functions, including protein sorting and transport, proliferation, and apoptosis. It is still ...