Posttransplant monomorphic Burkitt's lymphoma: clinical characteristics and outcome of a multicenter series.

Burkitt's monomorphic posttransplant lymphoproliferative disorder (B-PTLD) is an uncommon subtype of PTLD. Owing to the paucity of this complication, clinical characteristics and outcome has not been fully described. Clinical characteristics and outcomes of 20 patients diagnosed with B-PTLD from 10 transplant centers belonging to the GEL/TAMO group were reviewed. Median time from transplant to B-PTLD was 7.2 years. All the cases fulfill the morphologic and genetic criteria of B-PTLD, whereas Epstein-Barr virus (EBV) was detected in 70% of cases. Patients were treated with different chemotherapy combinations, and three patients received upfront rituximab monotherapy. The great majority of patients receiving CHOP-like regimens attained a complete response (CR) (73%), similar to that obtained with dose-intensive chemotherapy (83% CR). In contrast, patients receiving upfront rituximab monotherapy required subsequent chemotherapy. Two patients (10%) died during treatment due to infection. The median progression-free survival and overall survival (OS) were 16 months and 139 months, respectively. When analyzing variables predicting for OS, we found that patients with bone marrow involvement had an adverse prognosis, with a median OS of 6 months (p = 0.008). In conclusion, B-PTLD is an uncommon complication usually associated with EBV infection and with an aggressive clinical course, particularly in patients with bone marrow involvement. High-dose chemoimmunotherapy obtained similar responses to R-CHOP, suggesting that R-CHOP could be an adequate alternative for these patients. In contrast, rituximab monotherapy does not seem to be effective enough to control the disease.

Observation as the initial management strategy in patients with mantle cell lymphoma.

BACKGROUND: Patients with mantle cell lymphoma (MCL) follow a heterogeneous clinical course. While they generally require treatment initiation shortly after diagnosis, it is unclear whether deferring treatment in selected patients with an indolent clinical behavior affects their overall outcome. PATIENTS AND METHODS: In this population-based study, all patients diagnosed with MCL during 1998-2014 were identified in the British Columbia Cancer Agency Lymphoid Cancer Database. The associations between clinico-pathologic characteristics, including the expression of Ki67, SOX11, and TP53, and time to treatment (TtT) and OS were analyzed. RESULTS: A total of 440 patients with MCL were evaluated: 365 (83%) received early treatment and 75 (17%) were observed ≥3 months. In the observation group, 54 (72%) patients had a nodal presentation, 16 (21%) a non-nodal presentation, and 5 (7%) had only gastrointestinal involvement. Characteristics associated with deferred treatment included good performance status, no B symptoms, low LDH, non-bulky disease, non-blastoid morphology, and lower Ki67 values. The median TtT in the observation group was 35 months (range 5-79), and 60 (80%) patients were observed beyond 12 months. The median OS was significantly longer in the observation group than in the early treatment group (72 versus 52.5 months, respectively, P = 0.041). In multivariable analysis, treatment decision was not associated with OS [HR 0.804 (95% CI 0.529-1.221), P = 0.306]. CONCLUSIONS: A subgroup of patients with MCL may be safely observed from diagnosis without negatively impacting their outcomes, including patients with non-nodal presentation as well as asymptomatic patients with low burden nodal presentation and a low proliferative rate.

Targeting the proliferative and chemoresistant compartment in chronic lymphocytic leukemia by inhibiting survivin protein.

Chronic lymphocytic leukemia (CLL) cells located in proliferation centers are constantly stimulated by accessory cells, which provide them with survival and proliferative signals and mediate chemotherapy resistance. Herein, we designed an experimental strategy with the aim of mimicking the microenvironment found in the proliferative centers to specifically target actively proliferating CLL cells. For this, we co-cultured CLL cells and bone marrow stromal cells with concomitant CD40 and Toll-like receptor 9 stimulation. This co-culture system induced proliferation, cell-cycle entry and marked resistance to treatment with fludarabine and bendamustine. Proliferating CLL cells clustered together showed a typical morphology of activated B cells and expressed survivin protein, a member of the inhibitor of apoptosis family that is mainly expressed by CLL cells in the proliferation centers. With the aim of specifically targeting actively proliferating and chemoresistant CLL cells, we investigated the effects of treatment with YM155, a small-molecule survivin inhibitor. YM155 treatment suppressed the co-culture-induced survivin expression and that was sufficient to inhibit proliferation and effectively induce apoptosis particularly in the proliferative subset of CLL cells. Interestingly, sensitivity to YM155 was independent from common prognostic markers, including 17p13.1 deletion. Altogether, these findings provide a rationale for clinical development of YM155 in CLL.

NOTCH1 mutations identify a genetic subgroup of chronic lymphocytic leukemia patients with high risk of transformation and poor outcome.

NOTCH1 has been found recurrently mutated in a subset of patients with chronic lymphocytic leukemia (CLL). To analyze biological features and clinical impact of NOTCH1 mutations in CLL, we sequenced this gene in 565 patients. NOTCH1 mutations, found in 63 patients (11%), were associated with unmutated IGHV, high expression of CD38 and ZAP-70, trisomy 12, advanced stage and elevated lactate dehydrogenase. Sequential analysis in 200 patients demonstrated acquisition of mutation in one case (0.5%) and disappearance after treatment in two. Binet A and B patients with NOTCH1-mutated had a shorter time to treatment. NOTCH1-mutated patients were more frequently refractory to therapy and showed shorter progression-free and overall survival after complete remission. Overall survival was shorter in NOTCH1-mutated patients, although not independently from IGHV. NOTCH1 mutation increased the risk of transformation to diffuse large B-cell lymphoma independently from IGHV, with this being validated in resampling tests of replicability. In summary, NOTCH1 mutational status, that was rarely acquired during the course of the disease, identify a genetic subgroup with high risk of transformation and poor outcome. This recently identified genetic subgroup of CLL patients deserves prospective studies to define their best management.