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The purpose of this study is to correlate the presence of TP53 gene mutations with the clinical outcome of a cohort of patients with diffuse large B-cell lymphoma (DLBCL) assembled from 12 medical centers. TP53 mutations were identified in 102 of 477 patients, and the overall survival (OS) of patients with TP53 mutations was significantly worse than those with wild-type TP53 (P < .001).

In this investigation of radical formation and reaction in gamma- irradiated DNA and model compounds, we report the conversion of the guanine cation radical (one-electron oxidized guanine, G(.+)) to the C1' sugar radical and another sugar radical at the C3' or C4' position (designated C3'(.)/C4'(.)) by visible and UV photolysis. Electron spin resonance (ESR) spectroscopic investigations were performed on salmon testes DNA as well as 5'-dGMP, 3'-dGMP, 2'-deoxyguanosine and other nucleosides/nucleotides as model systems. DNA samples (25- 150 mg/ml D(2)O) were prepared with Tl(3+) or Fe(CN)(3-)(6) as electron scavengers. Upon gamma irradiation of such samples at 77 K, the electron-gain path in the DNA is strongly suppressed and predominantly G(.+) is found; after UV or visible photolysis, the fraction of the C1' sugar radical increases with a concomitant reduction in the fraction of G(.+). In model systems, 3'- dGMP(+.) and 5'-dGMP(+.) were produced by attack of Cl(.-)(2) on the parent nucleotide in 7 M LiCl glass. Subsequent visible photolysis of the 3'-dGMP(+.) (77 K) results predominantly in formation of C1'(.) whereas photolysis of 5'-dGMP(+.) results predominantly in formation of C3'(.)/C4'(.). We propose that sugar radical formation is a result of delocalization of the hole in the electronically excited base cation radical into the sugar ring, followed by deprotonation at specific sites on the sugar.

We sought to investigate the clinical characteristics and pathologic features and survival outcome of patients with diffuse large B-cell lymphoma (DLBCL) arising in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), since controversy regarding their prognosis exists in the literature. Twenty-one patients with DLBCL arising either concurrently with (n = 7) or subsequent to (n = 14) a diagnosis of NLPHL were identified in the Nebraska Lymphoma Study Group Registry. The clinical and pathologic features of the cases were evaluated, and survival analysis was performed from the time of diagnosis of DLBCL. The median time to the development of DLBCL in those with prior NLPHL was only one year (range, 0.5-24 years). The median age of the patients at the time of diagnosis of DLBCL was 46 years (range, 18-72 years) and the male to female ratio was 17:4. Ten patients presented with nodal DLBCL only, 6 patients presented with both nodal and extranodal involvement, and 5 patients presented with only extranodal DLBCL. Eleven patients had limited stage (I/II) disease and 10 had advanced stage (III/IV) disease. The median overall survival (OS) and failure-free survival (FFS) of the entire group was 35 months and 11 months, respectively, and the predicted 5-year OS and FFS was 31% and 18%, respectively. There were no significant differences in the survival outcomes between patients with DLBCL arising in NLPHL and age- and sex- matched patients with de novo DLBCL. Our findings suggest that patients with DLBCL arising in NLPHL have a prognosis similar to those with de novo DLBCL and should be treated aggressively.

Summary The resistance to arsenic trioxide (ATO) treatment is relatively common (55–80%) in multiple myeloma patients. This study found that ATO at clinically achievable concentrations (2–7 μmol/l) activated p38 mitogen‐activated protein kinase (MAPK) in both myeloma cell lines and primary myeloma cells, a finding not previously well‐documented in myeloma cells. Inhibition of p38 MAPK activation by pharmacological inhibitors (SB203580) or downregulation of p38 MAPK by siRNA significantly increased the apoptosis and/or growth inhibition induced by ATO treatment in myeloma cells. Combination of ATO and p38 MAPK inhibition abolished the interleukin‐6 enhanced protection of myeloma cells against ATO treatment. The ATO‐resistant cell line developed in our laboratory showed an increase in p38 MAPK activation. The increase of apoptosis by the combination of ATO and SB203580 was accompanied by the activation of caspase‐9 and caspase‐8 suggesting that both extrinsic and intrinsic apoptotic pathways are involved. Additionally, the p38 MAPK activation by ATO was associated with increased phosphorylation and upregulated expression of Heat shock protein 27. These results suggest that ATO‐induced p38 MAPK activation plays an important role in the resistance to ATO in myeloma cells and that p38 MAPK inhibition may overcome resistance to ATO treatment in myeloma patients.

Since Zap-70 expression in chronic lymphocytic leukemia (CLL) cells correlates with a lack of somatic mutation of the immunoglobulin variable heavy chain (IgVH) genes, it has been proposed as a surrogate marker for disease prognosis. However, published studies of Zap-70 expression have used different commercial antibodies and analytic strategies. This study was undertaken to determine if any strategy was broadly applicable in a clinical flow cytometry laboratory. Expression of Zap-70 was determined in 37 CLL patients using four different commercial antibodies. T, NK, and CLL cells were identified by immunophenotyping along with Zap-70 expression. Data was analyzed in terms of both percent of CLL cells expressing Zap-70 and the ratio of Zap-70 expression in CLL cells compared to that in T + NK cells. Three Zap-70 antibodies showed wide ranges of Zap-70 expression as a percentage of tumor cells, while a fourth gave consistently elevated results. Comparing the percent Zap-70 expression with any two antibodies gave poor correlations (r(2) = 0.45-0.63). Our results indicated that the previous analytical strategies were not reproducible. A ratio metric is proposed, which gave better correlations (r(2) as high as 0.95) and would allow separation of CLL patients with elevated or decreased Zap-70 expression.

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Large cell lymphoma (LCL) sometimes occurs concurrently or subsequently in patients with nodular lymphocyte-predominant Hodgkin disease (NLPHD). Although there is evidence of a clonal relationship between LCL and NLPHD, there has been no direct demonstration that the lymphocytic and histiocytic (L&H) cells in NLPHD are related to the tumor cells in LCL. We identified 2 cases of NLPHD with an associated LCL. Single L&H cells, the Reed-Sternberg cell variants in NLPHD, were isolated from immunostained tissue sections by micromanipulation, and the immunoglobulin heavy chain gene (IgH) complementarity determining region (CDR) III of the cells was amplified by the polymerase chain reaction (PCR). The products were compared with those obtained from microdissected LCL cells using polyacrylamide gel electrophoresis and nucleotide sequencing. The IgH CDRIII sequences from the L&H cells were related to each other, but also showed nucleotide substitutions, consistent with a germinal center origin. The sequences from the L&H cells also were related to those from the corresponding LCL cells. We have provided direct evidence through sequence analysis of the IgH CDRIII that the L&H cells are clonally related to the corresponding LCL arising in 2 cases of NLPHD.