Tomohiro Kinoshita

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma, nasal type

BACKGROUNDnPatients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.nnnPATIENTS AND METHODSnWe retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.nnnRESULTSnComplete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.nnnCONCLUSIONnThe current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.

Presentation and management of intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a rare disease entity of non-Hodgkin lymphoma according to the current WHO classification. This rare form of B-cell lymphoma is characterised by selective growth of tumour cells in the lumina of small vessels of various organs. Strange characteristics of IVLBCL, including the absence of marked lymphoadenopathy and the usually aggressive clinical behaviour, result in the delay of timely and accurate diagnosis and fatal complications. Thus, the prognosis of IVLBCL is extremely poor. The success achieved with the anti-CD20 chimeric monoclonal antibody, rituximab, represents an important milestone in the clinical practice of B-cell lymphoma. An advantage of adding rituximab to conventional chemotherapies has been shown, in the process of increasing our understanding of the clinical and pathological manifestations for IVLBCL. This Review describes the cutting edge of research on IVLBCL, and discusses the unsolved issues from biological and clinical perspectives to provide a better understanding of this rare lymphoma.

Down-regulation of CD20 expression in B-cell lymphoma cells after treatment with rituximab-containing combination chemotherapies: its prevalence and clinical significance

Although rituximab is a key molecular targeting drug for CD20-positive B-cell lymphomas, resistance to rituximab has recently been recognized as a considerable problem. Here, we report that a CD20-negative phenotypic change after chemotherapies with rituximab occurs in a certain number of CD20-positive B-cell lymphoma patients. For 5 years, 124 patients with B-cell malignancies were treated with rituximab-containing chemotherapies in Nagoya University Hospital. Relapse or progression was confirmed in 36 patients (29.0%), and a rebiopsy was performed in 19 patients. Of those 19, 5 (26.3%; diffuse large B-cell lymphoma [DLBCL], 3 cases; DLBCL transformed from follicular lymphoma, 2 cases) indicated CD20 protein-negative transformation. Despite salvage chemotherapies without rituximab, all 5 patients died within 1 year of the CD20-negative transformation. Quantitative reverse-transcription-polymerase chain reaction (RT-PCR) showed that CD20 mRNA expression was significantly lower in CD20-negative cells than in CD20-positive cells obtained from the same patient. Interestingly, when CD20-negative cells were treated with 5-aza-2-deoxycytidine in vitro, the expression of CD20 mRNA was stimulated within 3 days, resulting in the restoration of both cell surface expression of the CD20 protein and rituximab sensitivity. These findings suggest that some epigenetic mechanisms may be partly related to the down-regulation of CD20 expression after rituximab treatment.

Retrospective Analysis of Intravascular Large B-Cell Lymphoma Treated With Rituximab-Containing Chemotherapy As Reported by the IVL Study Group in Japan

PURPOSEnTo evaluate the safety and efficacy of rituximab-containing chemotherapies for intravascular large B-cell lymphoma (IVLBCL).nnnPATIENTS AND METHODSnWe retrospectively analyzed 106 patients (59 men, 47 women) with IVLBCL who received chemotherapy either with rituximab (R-chemotherapy, n = 49) or without rituximab (chemotherapy, n = 57) between 1994 and 2007 in Japan. The median patient age was 67 years (range, 34 to 84 years). The International Prognostic Index was high-intermediate/high in 97% of patients.nnnRESULTSnThe complete response rate was higher for patients in the R-chemotherapy group (82%) than for those in the chemotherapy group (51%; P = .001). The median duration of follow-up for surviving patients was 18 months (range, 1 to 95 months). Progression-free survival (PFS) and overall survival (OS) rates at 2 years after diagnosis were significantly higher for patients in the R-chemotherapy group (PFS, 56%; OS, 66%) than for patients in the chemotherapy group (PFS, 27% with P = .001; OS, 46% with P = 0.01). Multivariate analysis revealed that the use of rituximab was favorably associated with PFS (hazard ratio [HR], 0.45; 95% CI, 0.25 to 0.80; P = .006) and OS (HR, 0.42; 95% CI, 0.21 to 0.85; P = .016). Treatment-related death was observed in three patients (6%) who received R-chemotherapy and in five patients (9%) who received chemotherapy.nnnCONCLUSIONnOur data suggest improved clinical outcomes for patients with IVLBCL in the rituximab era. Future prospective studies of rituximab-containing chemotherapies are warranted.

Age-related Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorders: comparison with EBV-positive classic Hodgkin lymphoma in elderly patients.

Age-related Epstein-Barr virus-associated B-cell lymphoproliferative disorder (aEBVLPD) is a disease group characterized by EBV-associated large B-cell lymphoma in elderly without predisposing immunodeficiency. In nearly one- third of cases, aEBVLPD occurs as a polymorphous subtype with reactive cell-rich components, bearing a morphologic similarity to classic Hodgkin lymphoma (cHL). The aim of this study was to clarify clinicopathologic differences between the polymorphic subtype of aEBVLPD (n = 34) and EBV(+) cHL (n = 108) in patients aged 50 years or older. Results showed that aEBVLPD was more closely associated with aggressive clinical parameters than cHL, with a higher age at onset (71 vs 63 years); lower male predominance (male-female ratio, 1.4 vs 3.3); and a higher rate of involvement of the skin (18% vs 2%), gastrointestinal tract (15% vs 4%), and lung (12% vs 2%). aEBVLPD was histopathologically characterized by a higher ratio of geographic necrosis, greater increase (> 30%) in cytotoxic T cells among background lymphocytes, higher positivity for CD20 and EBNA2, and absence of CD15 expression. As predicted by the clinical profile, aEBVLPD had a significantly poorer prognosis than EBV(+) cHL (P < .001). The polymorphous subtype of aEBVLPD constitutes an aggressive group with an immune response distinct from EBV(+) cHL, and requires the development of innovative therapeutic strategies.

Central nervous system involvement in intravascular large B-cell lymphoma : A retrospective analysis of 109 patients

Intravascular large B‐cell lymphoma (IVLBCL) is a rare disease entity with a high incidence of central nervous system (CNS) involvement at diagnosis. To evaluate CNS involvement, particularly recurrence including progression on therapy and relapse of IVLBCL, we retrospectively analyzed 109 patients with IVLBCL receiving chemotherapies with or without rituximab. In 82 patients (75%) without CNS involvement at initial diagnosis, risk of CNS recurrence at 3u2003years was 25% with a median follow‐up in survivors of 39u2003months (range, 2–158u2003months). In 27 patients (25%) with CNS involvement at initial diagnosis, risk of CNS recurrence at 1u2003year was 25% with a median follow‐up in survivors of 18u2003months (range, 10–77u2003months). Duration from diagnosis to CNS recurrence tended to be short in patients with CNS involvement at diagnosis. No significant difference in risk of CNS recurrence was found between patients receiving chemotherapies with or without rituximab. On multivariate analysis skin involvement at initial diagnosis was identified as a predictive factor for CNS recurrence in patients without CNS involvement at diagnosis (hazard ratio, 5.27; 95% confidence interval, 1.59–17.4; Pu2003=u20030.007). Survival rate after CNS recurrence at 2u2003years was 12% in patients without CNS involvement at diagnosis. Central nervous system recurrence is a serious complication in IVLBCL patients and optimal strategies for CNS involvement should be established to obtain further improvements to clinical outcomes in the rituximab era. (Cancer Sci 2010)

Escape mechanisms from antibody therapy to lymphoma cells: downregulation of CD20 mRNA by recruitment of the HDAC complex and not by DNA methylation.

Although rituximab is a critical monoclonal antibody therapy for CD20-positive B-cell lymphomas, rituximab resistance showing a CD20-negative phenotypic change has been a considerable clinical problem. Here we demonstrate that CD20 mRNA and protein expression is repressed by recruitment of a histone deacetylase protein complex to the MS4A1 (CD20) gene promoter in CD20-negative transformed cells after treatment with rituximab. CD20 mRNA and protein expression were stimulated by decitabine (5-Aza-dC) in CD20-negative transformed cells, and was enhanced by trichostation A (TSA). Immunoblotting indicated that DNMT1 expression was first downregulated 1 day after treatment with 5-Aza-dC, but IRF4 and Pu.1, the transcriptional regulators of MS4A1, were still expressed with or without 5-Aza-dC. Interestingly, CpG methylation of the MS4A1 promoter was not observed in CD20-negative transformed cells without 5-Aza-dC. A chromatin immunoprecipitation (ChIP) assay indicated that the Sin3A-HDAC1 co-repressor complex was recruited to the promoter and dissociated from the promoter with 5-Aza-dC and TSA, resulting in histone acetylation. Under these conditions, IRF4 and Pu.1 were continually recruited to the promoter with or without 5-Aza-dC and TSA. These results suggest that recruitment of the Sin3A-HDAC1 complex is related to downregulation of CD20 expression in CD20-negative B-cells after treatment with rituximab.

Evaluation of organ involvement in intravascular large B-cell lymphoma by 18F-fluorodeoxyglucose positron emission tomography.

To evaluate the role of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in intravascular large B-cell lymphoma (IVLBCL), we retrospectively analyzed four consecutive IVLBCL patients receiving FDG-PET before treatment between May 2006 and November 2007. Patients were two men and two women (median age 62 years, range 54–76 years). All patients received bone marrow biopsies and random skin biopsies and two of the four patients underwent renal biopsy for diagnosis. Accuracy of FDG-PET for the detection of organ involvements was analyzed by comparing results of pathological findings. Concordant results with respect to bone marrow involvement were accurately obtained for two patients. Skin and renal involvements were undetectable by FDG-PET regardless of positive pathological findings. One patient with a false-negative FDG-PET result showed fewer lymphoma cells in the bone marrow specimen than patients with concordant FDG-PET results. These results suggest false-negative results for some types of organ involvement. Careful interpretation of the results of FDG-PET in IVLBCL is thus required.

Pretreatment total serum protein is a significant prognostic factor for the outcome of patients with peripheral T/natural killer-cell lymphomas

Peripheral T- and NK-cell lymphomas (PT/NKCLs) are relatively rare, and few studies have validated the International Prognostic Index (IPI) for PT/NKCLs in prospective clinical trials. Histopathological specimens from 136 patients, enrolled in six prospective multicenter trials of doxorubicin-containing regimens, with PT/NKCLs were reviewed by six hematopathologists following the WHO classification. This combined analysis demonstrated that the IPI was not predictive of prognosis for patients with PT/NKCLs as previously shown by GELA. In a univariate analysis, low total serum protein (TP) and albumin levels, gastrointestinal tract involvement, and histologic subtype (extranodal NK/T-cell lymphoma, nasal type, and peripheral T-cell lymphoma, unspecified) were significantly associated with reduced survival. In a multivariate analysis, TP (pu2009=u20090.004) and histologic subtype (pu2009=u20090.024) remained significant. We discuss the need to establish the importance and meaning of TP and to develop new strategies for patients with PT/NKCLs allowing for TP, especially with worse histologic subtypes.

Aberrant DNA methylation of the p57KIP2 gene is a sensitive biomarker for detecting minimal residual disease in diffuse large B cell lymphoma.

The detection of minimal residual disease (MRD) in bone marrow is very important in the clinical management of malignant lymphoma. So far, the assessment of MRD in cases of diffuse large B cell lymphoma (DLBCL) has had some technical limitations, such as requiring patient-specific primers and complicated experimental steps. To resolve these problems, we applied a tumor-specific epigenetic alteration of the p57KIP2 gene as a biomarker for detecting MRD in DLBCL. The methylation of the p57KIP2 gene was analyzed in 63 cases of DLBCL by methylation-specific real-time quantitative PCR. Methylation of the p57KIP2 gene was detected in 53 (84.1%) of these 63 cases of DLBCL. We could detect one p57KIP2 gene-methylated cell among 10,000 unmethylated cells by the serial dilution experiment. This sensitivity is proved to be equivalent to that of detection of bcl2/IgH rearrangement by real-time quantitative PCR. This sensitivity could be converted to the detection of two methylated genomes per reaction. Using clinical material, the same results were confirmed. In this study, we established a convenient and universal method for detecting MRD in DLBCL. This technique is applicable for over 80% of patients with DLBCL. This could promote systemic MRD studies in the area of DLBCL.