Yoshitaka Asakura

Frequent inactivation of A20 in B-cell lymphomas

A20 is a negative regulator of the NF-κB pathway and was initially identified as being rapidly induced after tumour-necrosis factor-α stimulation. It has a pivotal role in regulation of the immune response and prevents excessive activation of NF-κB in response to a variety of external stimuli; recent genetic studies have disclosed putative associations of polymorphic A20 (also called TNFAIP3) alleles with autoimmune disease risk. However, the involvement of A20 in the development of human cancers is unknown. Here we show, using a genome-wide analysis of genetic lesions in 238 B-cell lymphomas, that A20 is a common genetic target in B-lineage lymphomas. A20 is frequently inactivated by somatic mutations and/or deletions in mucosa-associated tissue lymphoma (18 out of 87; 21.8%) and Hodgkin’s lymphoma of nodular sclerosis histology (5 out of 15; 33.3%), and, to a lesser extent, in other B-lineage lymphomas. When re-expressed in a lymphoma-derived cell line with no functional A20 alleles, wild-type A20, but not mutant A20, resulted in suppression of cell growth and induction of apoptosis, accompanied by downregulation of NF-κB activation. The A20-deficient cells stably generated tumours in immunodeficient mice, whereas the tumorigenicity was effectively suppressed by re-expression of A20. In A20-deficient cells, suppression of both cell growth and NF-κB activity due to re-expression of A20 depended, at least partly, on cell-surface-receptor signalling, including the tumour-necrosis factor receptor. Considering the physiological function of A20 in the negative modulation of NF-κB activation induced by multiple upstream stimuli, our findings indicate that uncontrolled signalling of NF-κB caused by loss of A20 function is involved in the pathogenesis of subsets of B-lineage lymphomas.

Pneumocystis jiroveci pneumonia in relation to CD4+ lymphocyte count in patients with B-cell non-Hodgkin lymphoma treated with chemotherapy.

An increasing incidence of Pneumocystis jiroveci pneumonia (PCP) in patients with B-cell non-Hodgkin lymphoma (B-NHL) receiving rituximab treatment has been reported. We reviewed patients with B-NHL who underwent chemotherapy from 2004 to 2008 at our institution to identify risk factors for PCP development during and after chemotherapy. Among 297 patients with B-NHL, six developed PCP. Of 121 patients (41%) who received PCP prophylaxis with sulfamethoxazole–trimethoprim during chemotherapy, none developed PCP (0%), while among 176 patients (59%) who had no prophylaxis, six (3.4%) developed PCP at a median of 2 months (range: 1–3 months) after starting chemotherapy. Patients with CD4+ lymphocyte counts ≤200/mm3 before chemotherapy had a higher risk of developing PCP (p = 0.045), while a history of rituximab treatment was not related to PCP. CD4+ lymphocyte counts ≤200/mm3 during and after chemotherapy were observed in 18.9% of patients.

Deletion of the TNFAIP3/A20 gene detected by FICTION analysis in classical Hodgkin lymphoma

BackgroundThe TNFAIP3 gene, which encodes a ubiquitin-modifying enzyme (A20) involved in the negative regulation of NF-κB signaling, is frequently inactivated by gene deletions/mutations in a variety of B-cell malignancies. However, the detection of this in primary Hodgkin lymphoma (HL) specimens is hampered by the scarcity of Hodgkin Reed-Sternberg (HR-S) cells even after enrichment by micro-dissection.MethodsWe used anti-CD30 immunofluorescence with fluorescence in-situ hybridization (FISH) to evaluate the relative number of TNFAIP3/CEP6 double-positive signals in CD30-positive cells.ResultsFrom a total of 47 primary classical Hodgkin lymphoma (cHL) specimens, 44 were evaluable. We found that the relative numbers of TNFAIP3/CD30 cells were distributed among three groups, corresponding to those having homozygous (11%), heterozygous (32%), and no (57%) deletions in TNFAIP3. This shows that TNFAIP3 deletions could be sensitively detected using our chosen methods.ConclusionsComparing the results with mutation analysis, TNFAIP3 inactivation was shown to have escaped detection in many samples with homozygous deletions. This suggests that TNFAIP3 inactivation in primary cHL specimens might be more frequent than previously reported.

Comparison of outcomes after allogeneic hematopoietic stem cell transplantation in patients with follicular lymphoma, diffuse large B-cell lymphoma associated with follicular lymphoma, or de novo diffuse large B-cell lymphoma†

The outcome after allogeneic hematopoietic stem cell transplantation (allo‐HCT) for diffuse large B‐cell lymphoma (DLBCL) associated with follicular lymphoma (FL), which includes DLBCL with pre‐ or co‐existing FL, remains controversial, and few previous reports have compared the outcomes after allo‐HCT for FL, DLBCL associated with FL, and de novo DLBCL. We retrospectively analyzed 97 consecutive patients with FL (n = 46), DLBCL associated with FL (n = 22), or de novo DLBCL (n = 29) who received allo‐HCT at our institute between 2000 and 2010. With a median follow‐up of 53 months, the 5‐year overall survival (OS) and progression‐free survival (PFS) were, respectively, 77% and 70% for FL, 62% and 57% for DLBCL associated with FL, and 26% and 23% for de novo DLBCL. The 5‐year cumulative incidences of non‐relapse mortality and disease progression/relapse were, respectively, 16% and 15% for FL, 19% and 24% for DLBCL associated with FL, and 36% and 41% for de novo DLBCL. By a multivariate analysis, the OS and PFS for DLBCL associated with FL were significantly better than those for de novo DLBCL, whereas they were not significantly different from those for FL. These results suggest that allo‐HCT may be a promising option for patients with not only advanced FL but also DLBCL associated with FL. Am. J. Hematol. 2012.

Evaluation of two prognostic indices for adult T-cell leukemia/lymphoma in the subtropical endemic area, Okinawa, Japan

Aggressive adult T‐cell leukemia/lymphoma (ATL) has an extremely poor prognosis and is hyperendemic in Okinawa, Japan. This study evaluated two prognostic indices (PIs) for aggressive ATL, the ATL‐PI and Japan Clinical Oncology Group (JCOG)‐PI, in a cohort from Okinawa. The PIs were originally developed using two different Japanese cohorts that included few patients from Okinawa. The endpoint was overall survival (OS). Multivariable Cox regression analyses in the cohort of 433 patients revealed that all seven factors for calculating each PI were statistically significant prognostic predictors. Three‐year OS rates for ATL‐PI were 35.9% (low‐risk, n = 66), 10.4% (intermediate‐risk, n = 256), and 1.6% (high‐risk, n = 111), and those for JCOG‐PI were 22.4% (moderate‐risk, n = 176) and 5.3% (high‐risk, n = 257). The JCOG‐PI moderate‐risk group included both the ATL‐PI low‐ and intermediate‐risk groups. ATL‐PI more clearly identified the low‐risk patient subgroup than JCOG‐PI. To evaluate the external validity of the two PIs, we also assessed prognostic discriminability among 159 patients who loosely met the eligibility criteria of a previous clinical trial. Three‐year OS rates for ATL‐PI were 34.5% (low‐risk, n = 42), 9.2% (intermediate‐risk, n = 109), and 12.5% (high‐risk, n = 8). Those for JCOG‐PI were 22.4% (moderate‐risk, n = 95) and 7.6% (high‐risk, n = 64). The low‐risk ATL‐PI group had a better prognosis than the JCOG‐PI moderate‐risk group, suggesting that ATL‐PI would be more useful than JCOG‐PI for establishing and examining novel treatment strategies for ATL patients with a better prognosis. In addition, strongyloidiasis, previously suggested to be associated with ATL‐related deaths in Okinawa, was not a prognostic factor in this study.