伴MYD88 L265P突变的脾边缘区淋巴瘤临床特征分析

目的 分析伴MYD88 L265P突变的脾边缘区淋巴瘤(splenic marginal zone lymphoma,SMZL)患者的临床特征.方法 回顾性分析本中心SMZL患者队列,将MYD88 L265P突变型患者的临床特征与野生型以及华氏巨球蛋白血症(Waldenstr?m macroglobulinemia,W...     

淋巴浆细胞性淋巴瘤/华氏巨球蛋白血症10例临床病理学特征分析及MYD88基因突变检测

背景与目的：淋巴浆细胞性淋巴瘤/华氏巨球蛋白血症（lymphoplasmacytic lymphoma/Waldenström macroglobulinemia,LPL/WM）是罕见的B细胞惰性淋巴瘤,其诊断常需要与其他小B细胞性肿瘤作鉴别。本研究皆在探讨LPL/WM的临床病理学特点,并观察MYD88基因突变在此类肿瘤中的检出频率。方法：分析10例LPL/WM病例的临床资料、组织学形态和免疫组织化学表型,并以聚合酶链反应（polymerase chain reaction,PCR）扩增及直接测序法检测肿瘤标本MYD88基因的状态。结果：10例患者均为男性,中位年龄61岁。患者多表现为乏力和贫血,均有不同程度的IgM型免疫球蛋白血症和肿瘤骨髓累及。淋巴结活检标本光镜检查显示淋巴结结构部分存在,特别是可以见到开放的淋巴窦。肿瘤由数量不等的浆细胞、小淋巴细胞及浆样淋巴细胞组成。骨髓活检标本也可见到相同形态的细胞浸润。免疫组织化学染色显示,10例肿瘤细胞均呈CD20弥漫阳性并限制性表达免疫球蛋白轻链κ,6例瘤细胞表达CD23,2例部分瘤细胞表达CD5,未见病例表达CD10,Ki-67增殖指数在5%~30%之间。另外,2例LPL/WM在其病灶中尚可见到较多的IgG4阳性反应性浆细胞浸润。所有LPL/WM病例肿瘤组织均有MYD88 L265P突变检出,而对照组其他小B细胞性肿瘤均为阴性结果。结论：LPL/WM多具有典型的临床病理学形态,但偶亦可出现异常表型。MYD88 L265P作为LPL/WM的特征性遗传学特点,其检测的引入可使此类肿瘤的诊断和鉴别有更可靠的依据。     

Clinical significance of disease‐specific MYD88 mutations in circulating DNA in primary central nervous system lymphoma

Recent sequencing studies demonstrated the MYD88 L265P mutation in more than 70% of primary central nervous system lymphomas (PCNSL), and the clinical significance of this mutation has been proposed as diagnostic and prognostic markers in PCNSL. In contrast, mutational analyses using cell‐free DNAs have been reported in a variety of systemic lymphomas. To investigate how sensitively the MYD88 L265P mutation can be identified in cell‐free DNA from PCNSL patients, we carried out droplet digital PCR (ddPCR) and targeted deep sequencing (TDS) in 14 consecutive PCNSL patients from whom paired tumor‐derived DNA and cell‐free DNA was available at diagnosis. The MYD88 L265P mutation was found in tumor‐derived DNA from all 14 patients (14/14, 100%). In contrast, among 14 cell‐free DNAs evaluated by ddPCR (14/14) and TDS (13/14), the MYD88 L265P mutation was detected in eight out of 14 (ddPCR) and in 0 out of 13 (TDS) samples, implying dependence on the detection method. After chemotherapy, the MYD88 L265P mutation in cell‐free DNAs was traced in five patients; unexpectedly, the mutations disappeared after chemotherapy was given, and they remained undetectable in all patients. These observations suggest that ddPCR can sensitively detect the MYD88 L265P mutation in cell‐free DNA and could be used as non‐invasive diagnostics, but may not be applicable for monitoring minimal residual diseases in PCNSL.     

High‐resolution genomic profiling reveals clonal evolution and competition in gastrointestinal marginal zone B‐cell lymphoma and its large cell variant

We studied marginal zone B‐cell lymphomas of the gastrointestinal tract including seven small cell lymphomas, eight large cell areas of composite lymphomas and 13 large cell variants using SNP array profiling. We found an increase of genomic complexity with lymphoma progression from small to large cytology, and identified gains of prominent (proto) oncogenes such as REL, BCL11A, ETS1, PTPN1, PTEN and KRAS which were found exclusively in the large cell variants. Copy numbers of ADAM3A, SCAPER and SIRPB1 were varying between the three different modes of presentation, hence suggestive for aberrations associated with progression from small to large cell lymphoma. The number of aberrations was slightly higher in the large cell part of composite lymphomas than in large cell lymphomas, suggesting that clonal selection takes place and that composite lymphomas are in a transition state. To further investigate this, we comparatively analyzed samples of two morphologically different regions of the same small cell tumor with a BIRC3‐MALT1 translocation, as well as material acquired at two different time points from one composite lymphoma. We found genomic heterogeneity in both cases, supporting the theory of competing subclones in the evolution and progression of extranodal marginal zone B‐cell lymphoma.     

Practical diagnostic approaches to composite plasma cell neoplasm and low grade B‐cell lymphoma/clonal infiltrates in the bone marrow

Composite plasma cell neoplasm (PCN) and low grade B‐cell lymphoma (B‐NHL) in the bone marrow are uncommon and raise the differential diagnosis of B‐NHL with plasmacytic differentiation and PCN with lymphoplasmacytic morphology. This can be a challenging differential diagnosis, and the distinctions are important because of differences in management. We report five cases of composite PCN with B‐NHL or clonal B‐cell infiltrates involving the bone marrow. By using multiple different diagnostic modalities, including immunophenotyping by flow cytometry and immunohistochemistry, cytogenetic analysis and IGH gene rearrangement studies by polymerase chain reaction, we were able to distinguish two distinct clonally unrelated neoplasms in all cases. We describe the utility and pitfalls of these different diagnostic modalities. Flow cytometric analysis with a panel of antibodies that includes CD19, CD56, CD138, CD45 and other aberrant markers commonly expressed by PCN will allow identification of clonally unrelated PCN and B‐NHL in a composite neoplasm, and distinguish them from B‐NHL with plasmacytic differentiation and PCN with lymphoplasmacytic morphology. Cytogenetic and molecular analyses can give false‐negative or false‐positive results. In summary, a multimodal approach utilizing these different tools, including clinical data, should be used to arrive at the correct diagnosis. Copyright © 2014 John Wiley & Sons, Ltd.     

The use of droplet digital PCR in liquid biopsies: A highly sensitive technique for MYD88 p.(L265P) detection in cerebrospinal fluid

The gold standard for diagnosis of central nervous system lymphomas still regards a stereotactic brain biopsy, with the risk of major complications for the patient. As tumor cells can be detected in cerebrospinal fluid (CSF), CSF analysis can be used as an alternative. In this respect, mutation analysis in CSF can be of added value to other diagnostic parameters such a cytomorphology and clonality analysis. A well‐known example of targeted mutation analysis entails MYD88 p.(L265P) detection, which is present in the majority of Bing Neel syndrome and primary central nervous system lymphoma (PCNSL) patients. Unfortunately, tumor yield in CSF can be very low. Therefore, use of the highly sensitive droplet digital PCR (ddPCR) might be a suitable analysis strategy for targeted mutation detection. We analyzed 26 formalin fixed paraffin embedded (FFPE) samples (8 positive and 18 negative for MYD88 p.(L265P) mutation) by ddPCR, of which the results were compared with next generation sequencing (NGS). Subsequently, 32 CSF samples were analyzed by ddPCR. ddPCR and NGS results on FFPE material showed 100% concordance. Among the 32 CSF samples, 9 belonged to patients with lymphoplasmacytic lymphoma (LPL) and clinical suspicion of Bing Neel syndrome, and 3 belonged to patients with PCNSL. Nine of these samples tested positive for MYD88 p.(L265P) (8 LPL and 1 PCNSL). This study shows that sensitive MYD88 mutation analysis by ddPCR in CSF is highly reliable and can be applied even when DNA input is low. Therefore, ddPCR is of added value to current diagnostic parameters, especially when the available amount of DNA is limited.     

Extranodal marginal zone B‐cell lymphoma of the lung: experience with fludarabine and mitoxantrone‐containing regimens

Bronchial‐associated lymphoid tissue (BALT) lymphoma is an extranodal primary pulmonary lymphoma. The optimal therapy for this rare disease is still debated, and few heterogeneous data are available in literature. The aim of our study was to critically review data of patients with BALT lymphoma treated in first‐line therapy with fludarabine and mitoxantrone‐containing regimens (with or without rituximab) to investigate the effectiveness and the safety of this approach and patients' survival. An observational retrospective study was performed on homogenous clinical data from 17 patients with biopsy‐proven diagnosis of BALT. All the patients were treated with fludarabine and mitoxantrone‐containing regimen therapy. Radiological findings were also reviewed to assess the role of ¹⁸fluoro‐deoxyglucose positron emission tomography in the initial assessment and in the monitoring of this extranodal lymphoma. A high percentage of response was observed: 82.3% of patients achieved a complete response, 11.8% a partial response. Furthermore, a very remarkable progression‐free survival (71%) and overall survival (100%) were estimated at 14 years. No relevant toxicities were registered. Our results support the use of fludarabine and mitoxantrone‐containing regimens as first‐line therapy in the treatment of BALT lymphoma even if further data are necessary to consolidate our findings. Positron emission tomography scanning may provide additional valuable information in the assessment of BALT lymphoma. Copyright © 2012 John Wiley & Sons, Ltd.     

BCL6 gene rearrangement and protein expression are associated with large cell presentation of extranodal marginal zone B‐cell lymphoma of mucosa‐associated lymphoid tissue

Extranodal marginal zone B‐cell lymphoma of mucosa‐associated lymphoid tissue (MALT lymphoma) is an indolent B‐cell lymphoma, which is often localized in the stomach. It is characterized by typical morphology, immunology, cytogenetics and expression profile. The coexistence of a large B‐cell lymphoma and a MALT lymphoma in the gastrointestinal tract is defined as a composite lymphoma (ComL) and, as we have previously shown, is almost always the consequence of secondary transformation of MALT lymphoma. Here, we have analyzed a panel of seven MALT lymphomas, seven ComL and thirteen large cell variants of marginal zone B‐cell lymphomas (MZBL) using FISH for the detection of rearrangements of IGH, MALT1, BCL6, BCL10 and FOXP1 and immunohistochemistry for Bcl6, Bcl10 and FoxP1. Translocations involving IGH were found in 10/27 lymphomas including two cases with IGH‐BCL6 fusion and one with IGH‐BCL10 fusion; in 7/10 cases, the translocation partner was not identified. Bcl10 and FoxP1 protein expression was heterogeneous throughout the series. Genetic rearrangements of BCL6 and Bcl6 protein expression were found almost exclusively in the large cell components of the ComL and the large cell extranodal MZBL (p = 0.2093 and p = 0.0261, respectively). These findings suggest Bcl6 as a marker for transformation of MALT lymphoma.     

BCL2 mutation spectrum in B‐cell non‐Hodgkin lymphomas and patterns associated with evolution of follicular lymphoma

BCL2 is a target of somatic hypermutation in t(14;18) positive and also in a small fraction of t(14;18) negative diffuse large B‐cell lymphoma (DLBCL), suggesting an aberrant role of somatic hypermutation (ASHM). To elucidate the prevalence of BCL2 mutations in lymphomas other than DLBCL, we Sanger‐sequenced the hypermutable region of the BCL2 gene in a panel of 69 mature B‐cell lymphomas, including Richter's syndrome DLBCL, marginal‐zone lymphomas, post‐transplant lymphoproliferative disorders, HIV‐associated and common‐variable immunodeficiency‐associated DLBCL, all known to harbour ASHM‐dependent mutations in other genes, as well as 16 t(14,18) negative and 21 t(14;18) positive follicular lymphomas (FLs). We also investigated the pattern of BCL2 mutations in longitudinal samples from 10 FL patients relapsing to FL or transforming to DLBCL (tFL). By direct sequencing, we found clonally represented BCL2 mutations in 2/16 (13%) of t(14;18) negative FLs, 2/16 (13%) HIV‐DLBCLs, 1/9 (11%) of Richter's syndrome DLBCL, 1/17 (6%) of post‐transplant lymphoproliferative disorders and 1/2 (50%) common‐variable immunodeficiency‐associated DLBCL. The proportion of mutated cases was significantly lower than in FLs carrying the t(14;18) translocation (15/21, 71%). However, the absence of t(14;18) by FISH or PCR and the molecular features of the mutations strongly suggest that BCL2 represents an additional target of ASHM in these entities. Analysis of the BCL2 mutation pattern in clonally related FL/FL and FL/tFL samples revealed two distinct scenarios of genomic evolution: (i) direct evolution from the antecedent FL clone, with few novel clonal mutations acquired by the tFL major clone, and (ii) evolution from a common mutated long‐lived progenitor cell, which subsequently acquired distinct mutations in the FL and in the relapsed or transformed counterpart. Copyright © 2014 John Wiley & Sons, Ltd.     

PD‐L1 expression is low in large B‐cell lymphoma with MYC or double‐hit translocation

In large B‐cell lymphoma (LBCL), MYC translocation and MYC/BCL2 or MYC/BCL6 double hit (DH) are associated with poor prognosis, and there is an unmet need for novel treatment targets in this patient group. Treatments targeting the PD‐L1/PD‐1 pathway are still poorly elucidated in LBCL. PD‐L1 expression might predict response to treatment targeting the PD‐L1/PD‐1 pathway. We therefore investigated the relationship between PD‐L1 protein and mRNA expression levels and MYC and DH translocation in LBCL. We detected MYC, BCL2, and BCL6 translocation by fluorescent in situ hybridization in tissue samples from 130 patients randomly selected from two cohorts of patients with LBCL: 49 patients with MYC translocation of whom 36 had DH and 81 without MYC translocation. PD‐L1 protein expression was detected by immunohistochemistry (IHC) in tissue samples from 77 patients and PD‐L1 mRNA expression by next‐generation RNA sequencing (NGS) in another 77 patients. Twenty‐four patients overlapped, ie, were analysed with both IHC and NGS. Nonparametric tests were performed to evaluate intergroup differences. PD‐L1 protein expression level was significantly lower in patients with MYC (n = 42, median = 3.3%, interquartile range [IQR] 0.0‐10.8) or DH translocations (n = 31, median = 3.3%, IQR 0.0‐10.0) compared with patients with no MYC (n = 35, median = 16.7%, IQR 3.3‐30.0) or no DH translocations (n = 46, 13.3%, IQR 2.5‐30.0), P = .004 and P ≤ .001, respectively. PD‐L1 mRNA expression was also significantly lower in patients with MYC or DH translocations, P = .001 and P = .006, respectively. Higher PD‐L1 protein and mRNA expression levels were associated with non–germinal centre (GC) type compared with germinal centre B‐cell (GCB)‐type diffuse LBCL (DLBCL), P = .004 and P = .002, respectively. In conclusion, we report an association between low PD‐L1 expression and MYC and DH translocation in patients with LBCL. Our findings may indicate that patients with MYC or DH translocation may benefit less from treatment with PD‐L1/PD‐1‐inhibitors compared with patients without these translocations. This should be evaluated in larger, prospective, consecutive trials.     

Treatment of gastric marginal zone B‐cell lymphoma of the mucosa‐associated lymphoid tissue with rituximab,cyclophosphamide, vincristine and prednisone

There is no standard treatment for patients with gastric marginal zone B‐cell lymphoma of the mucosa‐associated lymphoid tissue (MALT lymphoma) who are resistant to, or ineligible for, anti‐Helicobacter pylori (anti‐HP) therapy. In this study, we investigated the activity of the rituximab, cyclophosphamide, vincristine and prednisone (R‐CVP) regimen in patients with gastric MALT lymphoma. Patients were included provided they had untreated gastric MALT lymphoma (except for anti‐HP therapy) and were resistant to, or ineligible for, anti‐HP therapy. Treatment plan consisted of six to eight 21‐day cycles of the R‐CVP chemotherapy regimen. Toxicity, response, relapse and survival were evaluated. Twenty patients (12 women and 8 men) were included in the analyses with median age of 59 years. Thirteen patients (65%) had stage I tumours, and seven patients (35%) had stages II–IV tumours. The overall response rate was 100%, with 19 (95%) complete responses and one (5%) partial response. Regimen toxicity was mild and mainly hematological, and no cases of gastric bleeding or perforation occurred. After a median follow‐up of 56.3 months, three patients had relapsed, and 19 patients remained alive (specific lymphoma survival 100%), of whom 17 had no evidence of disease. In our experience, the R‐CVP regimen is a well‐tolerated and effective treatment for patients with gastric MALT lymphoma who are resistant to, or ineligible for, anti‐HP therapy. Copyright © 2013 John Wiley & Sons, Ltd.     

Relapse in stage I(E) diffuse large B‐cell lymphoma

Despite a general favourable outcome in limited stage diffuse large B‐cell lymphoma (DLBCL), relapses occur in about 10 to 20% of patients. Prognostic models only partially identify patients at risk for relapse. Moreover, it is not known whether the outcome after such a relapse is similar to the outcome after relapse in advanced stages. From January 2004 through December 2012, all newly diagnosed patients with stage I(E) DLBCL were retrospectively analysed from 2 clinical databases to investigate the relapse pattern and outcome in relation to initial treatment and clinical characteristics. In 126 patients (median age 64 years), histologically confirmed stage I(E) DLBCL was diagnosed. With a median follow‐up of 53 months (range 5‐132 months), 1 progressive disease and 18 relapses occurred. The 5‐year time to tumour progression and disease‐specific survival were 85% (95% CI 79‐91%) and 92% (95% CI 87%‐97%), respectively. We observed no significant difference in relapse localization, time to tumour progression, and disease‐specific survival between patients treated with abbreviated R‐CHOP plus involved field radiotherapy or with 6 to 8 cycles of R‐CHOP. Analysis of relapses showed relapse >5 years after initial treatment (late relapse) in 5 of 19 patients (26%). Six of 19 patients (32%) had central nervous system relapse. Three of 11 relapsed cases available for analysis (28%) showed an MYC translocation, suggesting an overrepresentation in the relapse group. Outcome of patients with a relapse was poor with a median survival after relapse of 8 months. Only 1 patient (5%) underwent successful autologous stem cell transplantation. To improve outcome in these patients, early identification of new biological factors such as a MYC translocation or a high risk for CNS dissemination might be helpful. Moreover, treatment of any relapse after stage I disease should be taken seriously. Salvage treatment should be similar to relapses after advanced DLBCL.     

Phase I study of tirabrutinib (ONO‐4059/GS‐4059) in patients with relapsed or refractory B‐cell malignancies in Japan

We evaluated the safety, efficacy, pharmacokinetics, pharmacodynamics and predictive biomarkers of tirabrutinib, a second‐generation, enhanced‐selectivity Bruton's tyrosine kinase inhibitor in Japanese patients with relapsed/refractory B‐cell non?Hodgkin lymphoma (B‐cell NHL) and chronic lymphocytic leukemia (CLL). This was an open‐label, multicenter, phase I study. Seventeen patients (male N = 8) with a median age of 70 years were enrolled in 4 dose cohorts (160 mg once daily [N = 3], 320 mg once daily [N = 3], 480 mg once daily [N = 4] and 300 mg twice daily [N = 7]); 4 patients had continued tirabrutinib administration as of 4 January 2018. The maximum tolerated dose was not reached. Pneumonitis (N = 1) was the dose‐limiting toxicity for 300 mg twice daily. Common adverse events (AEs) were rash (35.3%) and vomiting (29.4%). Eight patients (47.1%) developed grade ≥3 AEs: neutropenia (23.5%), anemia (11.8%) and leukopenia (11.8%) were frequent. The overall response rate (≥PR) was 76.5% (13/17 patients), including 4 DLBCL patients with no CD79A/B or MYD88 mutations, and 1 CLL patient with a TP53 mutation, providing promising data for future developments. Of 16 patients with measurable lesions during the screening period, 12 showed ≥50% reductions in tumor diameter. In many patients, the tumor size decreased soon after beginning treatment. The maximum serum concentration for tirabrutinib was 611, 1220, 1280 and 886 ng/mL on Day 1 and 484, 971 1940, and 961 ng/mL on Day 28 for Cohorts 1‐4, respectively. Tirabrutinib pharmacokinetics were linear, with little accumulation following multiple doses. Tirabrutinib was well tolerated and showed promising efficacy for B‐cell NHL/CLL.     

CD26 expression in mature B‐cell neoplasia: its possible role as a new prognostic marker in B‐CLL

CD26 (dipeptidyl peptidase IV, DPP IV) is widely expressed by T and natural killer (NK) cells, epithelial and endothelial cells of different tissues, and it is strongly upregulated in activated B‐cells; moreover it plays a regulatory role in the neoplastic transformation and progression of various types of tumours. CD26 expression was evaluated by means of flow cytometry in various peripheral B‐cell lymphoid tumours: 12 follicular and 12 mantle cell lymphomas, 20 multiple myelomas (MMs), 12 hairy cell leukaemias (HCLs), 112 chronic lymphocytic leukaemias (CLLs), 20 CD5^negative B‐cell chronic lymphoproliferative diseases (CD5^neg B‐CLPDs) and 12 diffuse large cell lymphomas (DLCLs). CD26 expression was absent or barely detectable in follicular and mantle cell lymphomas, high in MMs and HCLs, and variable in CLLs, in CD5^neg B‐CLPDs and in DLCLs. CD26 significantly correlated with CD49d and CD38 expressions (p < 0.0001) in B‐CLLs, and there was a significant correlation between CD26 and ZAP‐70 expressions or IgVH mutational status (p < 0.0001). After a median follow‐up of 36 months, 65 B‐CLL patients were treated; taking 10% as the best CD26 cut‐off value, Kaplan–Meier curves revealed a significantly shorter time to treatment in the CD26‐positive cases (p < 0.0001). Overall, our data indicate that CD26 expression may identify subsets of B‐CLL patients with an unfavourable clinical outcome in terms of therapeutic need, thus suggesting its potential role as a marker (together with CD38 and CD49d) in a future routine cytofluorimetric panel to be validated for the prognostic stratification of B‐CLLs. Copyright © 2009 John Wiley & Sons, Ltd.     

Role of 18F‐FDG‐PET/CT in the management of marginal zone B cell lymphoma

The use of PET in patients with marginal zone B cell lymphoma (MZL) is controversial because of variability of fluorodeoxyglucose (FDG) avidity. We analyzed 40 PET/CT in 25 consecutive patients to compare its performance with CT at staging and as a first‐line response assessment. Sensitivity of PET/CT and CT was 96 and 76%. Mean standard uptake value was 6.1, 6.9 and 3.4 (p = 0.3) in nodal, extranodal and splenic subtypes, respectively. Of 17 patients (extranodal: n = 9; nodal: n = 6; splenic subtype: n = 2) with both imaging tests available at diagnosis, 8 (47%) had more involved areas with PET/CT than with CT, 75% of which were extranodal lesions. PET/CT resulted in upstaging of five patients although treatment of only two of them was changed. Responses of 15 patients with post‐treatment PET/CT were the following: 9 negative and 6 positive of which 3 were isolated residual lesions. Progression was documented in two of these three patients. Response was also assessed by CT in 11 patients. Discrepancies were found in three: Two were in complete remission by CT while PET/CT detected localized residual disease; another patient was in partial remission by CT, whereas PET/CT showed only one positive lesion. Two of these three patients relapsed. Patients with negative post‐treatment PET/CT did not relapse. With a median follow‐up of 50 months (10–152 months), 3‐year overall survival was 100 and 80% for patients with negative and positive post‐treatment PET/CT (p = 0.2). Three‐year disease‐free survival was 86%; the negative predictive value (NPV) was 100%, and the positive predictive value (PPV) was 83.3%. Although a larger number of patients will be required to further confirm these data, we can conclude that PET/CT is a useful imaging tool for both staging and response assessment in patients with nodal and extranodal MZL as a result of its high sensitivity, NPV and PPV. Copyright © 2014 John Wiley & Sons, Ltd.     

Long‐term safety and activity of cladribine in patients with extranodal B‐cell marginal zone lymphoma of the mucosa‐associated lymphoid tissue (MALT) lymphoma

The purine analogue 2‐chloro‐deoxyadenosine (2‐CDA, cladribine) +/? rituximab has been successfully tested in mucosa‐associated lymphoid tissue lymphoma (MALT lymphoma) patients. However, studies using cladribine in other indications have reported the potential for prolonged hematological side effects and secondary hematologic and non‐hematologic malignancies. To date, there have been no data on long‐term effects of cladribine in MALT lymphoma patients. We have analyzed a large number of 49 patients treated with cladribine at our institution 1997–2011. All patients were treated within clinical trials and had undergone a standardized follow‐up protocol minimizing a potential bias in the detection of late sequels and relapses. After a median follow‐up time of 61 months (interquartile range: 43–72) for 49 analyzed patients, 35 (71%) are alive, while 14 (29%) have died. In the entire collective, three cases (6%) of prolonged pancytopenia including manifest myelodysplastic syndrome in one patient (2%), three cases (6%) of secondary lymphoid malignancies, and five cases (10%) of non‐hematologic cancers were documented. In terms of outcome, 42/49 (86%) patients responded to cladribine‐containing treatment, and only 10/42 (24%) responding patients needed further treatment after a median time to progression of 14 months (interquartile range, 8–34). Currently, 25/35 (71%) patients being alive are in ongoing complete remission and 2/35 (6%) in ongoing stable disease, respectively. Eight patients (23%) are free of lymphoma after second‐line therapy, with the median overall survival not having been reached. Our data suggest that cladribine might be safely applied in patients with MALT lymphoma, also in terms of long‐term toxicities. These data also confirm the potential of cladribine to induce durable remissions. Copyright © 2015 John Wiley & Sons, Ltd.     

Clinical characteristics and outcome analysis of pediatric B‐cell non‐Hodgkin's lymphoma. Experience with FAB‐LMB 96 and UKCCSG B‐cell NHL guidelines in a developing country

Aim: To analyze the clinical characteristics of B‐cell non‐Hodgkin's lymphoma (NHL) patients and the therapeutic efficacy of French‐American‐British Lymphoma Malins de Burkitt 96 and the recent United Kingdom Children's Cancer Study Group B‐cell NHL guidelines in the tertiary care hospital of a developing country. Methods: Patients aged ≤18 years registered at our hospital between January 1995 and December 2006 with histologically proved B‐Cell NHL were selected for retrospective analysis. Results: Of the total of 131 patients registered, 122 patients were eligible for evaluation. Of these 95 had Burkitt's lymphoma, 22 diffuse large B‐cell lymphoma and five had B‐cell NHL not otherwise specified. The mean age was 8.4 years. Overall 42 children had a baseline weight less than the 10th centile. A total of 37 had uric acid >10 mg/dl and 55 had a lactate dehydrogenase level >500; 73 had stage III and 31 had stage IV while only four presented at stage I and 14 at stage II. The abdomen was the commonest site of disease. A total of 45 patients died; 28 due to infection, nine due to tumor lysis syndrome and six of uncontrolled disease. All deaths occurred within an average of 35 days from starting treatment. Our 5‐year overall survival rate was 68 percent and our event‐free survival was 55 percent. Conclusion: Late presentation with advanced disease, poor nutritional status and high risk of exposure to infective agents all contribute to the high mortality in patients treated with intensive protocols in resource‐poor countries.     

Anti‐tumor activity of WK88‐1, a novel geldanamycin derivative,in gefitinib‐resistant non‐small cell lung cancers with Met amplification

Although epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKIs) have been introduced for the treatment of non‐small cell lung cancer (NSCLC), the emergence of secondary T790M mutation in EGFR or amplification of the Met proto‐oncogene restrain the clinical success of EGFR‐TKIs. Since heat shock protein‐90 (Hsp90) stabilizes various oncoproteins including EGFR and c‐Met, the inhibition of Hsp90 activity appears as a rational strategy to develop anticancer drugs. Despite preclinical efficacy of geldanamycin‐anasamycin (GA)‐derivatives containing benzoquinone moiety as Hsp90 inhibitors, the hepatotoxicity of these GA‐derivatives restricts their therapeutic benefit. We have prepared WK‐88 series of GA‐derivatives, which lack the benzoquinone moiety. In this study, we have examined the anticancer effects of WK88‐1 in Met‐amplified‐ and gefitinib‐resistant (HCC827GR) NSCLC cells and its parental HCC827 cells. Treatment with WK88‐1 reduced the cell viability in both HCC827 and HCC827GR cells, which was associated with marked decrease in the constitutive expression of Hsp90 client proteins, such as EGFR, ErbB2, ErbB3, Met and Akt. Moreover, WK88‐1 attenuated phosphorylation of these Hsp90 client proteins and reduced the anchorage‐independent growth of HCC827GR cells. Administration of WK88‐1 did not cause hepatotoxicity in animals and significantly reduced the growth of HCC827GR cells xenograft tumors in nude mice. Our study provides evidence that ErbB3 might be a client for Hsp90 in Met‐amplified NSCLCs. In conclusion, we demonstrate that inhibition of Hsp90 dampens the activation of EGFR‐ or c‐Met‐mediated survival of Met‐amplified NSCLCs and that WK88‐1 as a Hsp90 inhibitor alleviates gefitinib resistance in HCC827GR cells.