Complementarity determining region-III is a useful molecular marker for the evaluation of minimal residual disease in mantle cell lymphoma

Bone marrow (BM) and peripheral blood (PB) involvement in 10 patients with mantle cell lymphoma (MCL) was analysed by a polymerase chain reaction (PCR)-mediated RNase protection assay. The complementarity determining regions (CDR)-III of all 10 MCLs examined was amplified efficiently with consensus V_H and J_H primers by PCR, and BM and/or PB involvement was evaluated by RNase protection assay in all 10 patients examined. Our assay showed BM and/or PB of the entire group to have neoplastic cells at presentation, despite the fact that eight patients were found to have BM and/or PB involvement on the basis of morphological examination and/or surface marker analysis. We also examined minimal residual disease (MRD) after conventional chemotherapy, and detected MRD in a patient in complete remission (CR). Although previous studies have shown that t(11;14) breakpoint amplification by PCR was only applicable to about 30–40% of cases, the present study indicates that CDR-III is a useful molecular marker and the PCR-mediated RNase protection assay is a good tool for the evaluation of MRD in MCL. It is suggested that BM and PB of MCL patients are quite frequently involved at presentation and even after conventional chemotherapy at the molecular level.     

Cyclin D1 protein analysis in the diagnosis of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a clinicopathologic entity that is difficult to diagnose on histopathologic criteria. Approximately 50% to 70% of MCL contain a t(11;14)(q13;q32) translocation involving the cyclin D1 gene. Irrespective of this rearrangement, almost all MCL show overexpression of the cyclin D1 gene at the mRNA level. Other B-cell non-Hodgkin's lymphomas (NHL) do not show this rearrangement or overexpression of cyclin D1. We developed an immunohistochemical assay to detect overexpression of the cyclin D1 protein on conventional formalin-fixed, paraffin-embedded biopsies using the well-defined monoclonal antibody DCS-6. Expression in tumor cells was compared with expression of cyclin D1 in endothelial cells and fibroblasts. An exclusively nuclear staining pattern was observed. Moreover, expression was directly compared with the expression observed by immunoblot analysis with the same antibody, as well as with mRNA expression and with the occurrence of genomic rearrangements within the BCL-1 locus. Of 13 MCL that were analyzed by immunohistochemistry and immunoblot, 12 showed overexpression with both techniques, whereas no overexpression was observed in 39 other NHL. Of 13 additional MCL studied either by immunohistochemistry or immunoblot, 11 also showed overexpression. Two lymphomas morphologically indistinguishable from MCL but with an aberrant immunophenotype (CD5 negative, CD10 positive) both lacked overexpression of cyclin D1. These results underscore the significance of overexpression of the cyclin D1 protein as a specific marker for MCL. Detection of cyclin D1 overexpression on formalin-fixed, paraffin- embedded tissues using the DCS-6 monoclonal antibody can be applied for routine diagnostic purposes.     

Blastoid variant of mantle cell lymphoma: late progression from classical mantle cell lymphoma and quantitation of minimal residual disease

OBJECTIVES: Classical mantle cell lymphoma (MCL) and its blastoid variant (MCL-BV) are characterized by an extremely poor prognosis. Long-time survivors are rare, only very few patients with an overall survival over 10 years have been reported. We present a case of a 41-year-old male with a 12 yr history of MCL stage I to show, that very late relapses in MCL are possible and may present as a transformation into an aggressive blastoid variant and to illustrate the value of quantitative minimal residual disease (MRD) monitoring for treatment guidance. METHODS: Diagnostic lymph node and bone marrow samples were investigated by immunohistochemistry. Clonality analysis was performed by immunoglobulin heavy chain gene (IGVH) and t(11;14) PCR. The MRD assessment was done by real-time quantitative PCR (RQ-PCR) on available follow-up samples. RESULTS: By histologic review and sequencing of the clonal IGVH and t(11;14) PCR products we demonstrated a common clonal origin of the leucemic MCL-BV and the classical MCL diagnosed 12 yr earlier. Quantitative MRD assessment revealed significant MRD levels after intensive conventional chemotherapy including Rituximab. Therefore, treatment was early intensified by myeloablative radio-chemotherapy and allogeneic peripheral stem cell transplantation from an unrelated HLA-identical donor. This did not translate into a sustained remission as reflected by persisting MRD levels after transplantation and the patient died from rapid progressive disease 3.5 months after transplant. CONCLUSION: This report presents a rare case of long-term survivor of MCL with a progression of the original MCL cell clone to MCL-BV and demonstrates the clinical value of quantitative MRD assessment for optimized therapeutic management.     

Cyclin D1-negative mantle cell lymphoma: a clinicopathologic study based on gene expression profiling

Cyclin D1 overexpression is believed to be essential in the pathogenesis of mantle cell lymphoma (MCL). Hence, the existence of cyclin D1-negative MCL has been controversial and difficult to substantiate. Our previous gene expression profiling study identified several cases that lacked cyclin D1 expression, but had a gene expression signature typical of MCL. Herein, we report the clinical, pathologic, and genetic features of 6 cases of cyclin D1-negative MCL. All 6 cases exhibited the characteristic morphologic features and the unique gene expression signature of MCL but lacked the t(11;14)(q13; q32) by fluorescence in situ hybridization (FISH) analysis. The tumor cells also failed to express cyclin D1 protein, but instead expressed either cyclin D2 (2 cases) or cyclin D3 (4 cases). There was good correlation between cyclin D protein expression and the corresponding mRNA expression levels by gene expression analysis. Using interphase FISH, we did not detect chromosomal translocations or amplifications involving CCND2 and CCND3 loci in these cases. Patients with cyclin D1-negative MCL were similar clinically to those with cyclin D1-positive MCL. In conclusion, cases of cyclin D1-negative MCL do exist and are part of the spectrum of MCL. Up-regulation of cyclin D2 or D3 may substitute for cyclin D1 in the pathogenesis of MCL.     

NPM1 mutation is a stable marker for minimal residual disease monitoring in acute myeloid leukaemia patients with increased sensitivity compared to WT1 expression

Mutation in the NPM1 gene occurs in 60% of acute myeloid leukaemia (AML) patients with normal karyotype. NPM1 mutation is potentially a superior minimal residual disease (MRD) marker compared to WT1 gene overexpression by being specific to the malignant clone, although experimental evidence published so far includes very limited numbers of relapsed cases. Also, the stability of the NPM1 mutation has been questioned by reports of the mutation being lost at relapse. In the present study we compared NPM1 mutation and WT1 overexpression as MRD markers in 20 cases of relapsed AML. The 20 patients experienced a total of 28 morphological relapses. Karyotypic evolution was detected in 56% of relapses. All relapses were accompanied by high levels of NPM1 mutation, along with high WT1 mRNA levels, thus demonstrating complete stability of both markers during relapse. Detectable NPM1 mutation following a period of morphological remission was accompanied by a morphological relapse in all cases. In contrast, WT1 expression was detected in 33% of the NPM1 mutation negative samples. This background WT1 expression produced by non-leukaemia cells was highly variable, both between and within patients, and limited the de facto sensitivity of the WT1 expression analysis. The present study therefore provides important experimental evidence demonstrating that NPM1 mutation is superior to WT1 overexpression as marker of MRD in NPM1-mutated AML, even in the presence of extensive karyotypic evolution.     

Molecular monitoring of minimal residual disease in patients with multiple myeloma

Improvement of transplantation strategies and a multitude of emerging novel therapies result in a better treatment outcome in patients with multiple myeloma (MM). This gives rise to the need for sensitive methods to detect minimal residual disease (MRD) in MM. Qualitative molecular monitoring using allele-specific oligonucleotide PCR for the immunoglobulin heavy chain (IgH) is well established to detect clonotypic cells after therapy or in stem cell harvests. Recently, real-time IgH PCR or limiting dilution based PCR assays offer the possibility to quantify the amount of residual tumour cells. In this review, different qualitative and quantitative IgH PCR techniques will be discussed as well as the current clinical role of molecular monitoring of MRD in patients with MM.     

以降钙素基因高度甲基化为分子基因标志检测白血病微量残留病

目的 探讨以降钙素（CT）基因高度甲基化为白血病克隆的分子基因标志,检测白血病微量残留病（MRD）,并预测预后的可能性。方法 用限制性内切酶消化DNA〈应用聚合酶链反应（PCR）技术检测载9例急性白血病（AL）,其中急性淋巴细胞白血病（ALL）14例,急性非淋巴细胞白血病（ANLL）15例和8例慢性粒细胞白血病（CML）急变患者的CT基因的甲基化程度,对CT基因高度甲基化阳性者,以CT基因高度甲基化为白血病克隆的分子基因标志,应用PCR技术定期追踪检测骨髓MRD。结果 ALL中CT基因高度甲基化阳性率为857%（12/14）,ANLL为60%（9/15）,CML急变为100%（8/8）,而对照组无一例阳性,20例AL和CML急变患者完全缓解（CR）后均存在MRD,CR后MRD持续阳性或转阴后再次出现阳性,提示将发生骨髓复发,能提早2-11个月预示疾病的复发,MRD较早转阴并持续长期阴性者可能获得长期自下而上度。结论 以CT基因高度甲基化为白血病克隆的分子基因标志,应用PCR技术能起到监测白血病MRD的作用。为预测白血病的预后开辟了一条新途径。     

Correlation of minimal residual disease cell frequency with molecular genotype in patients with acute myeloid leukemia

Background

About 70–80 percent of patients with acute myeloid leukemia enter complete remission, but at least half of these patients who achieve remission go on to relapse. Improved treatment is likely to come from increasing the time to relapse, especially for younger patients. With the vastly increasing number of targeted therapies there is a strong need for short-term end-points to efficiently test such therapies for further pursuance. Minimal residual disease assessment may offer such an end-point since it is a strong independent prognostic factor. As proof of principle we examined this concept for FLT3-ITD status at diagnosis.

Design and Methods

We determined FLT3-ITD status in bone marrow samples from 196 patients with newly diagnosed acute myeloid leukemia. The frequencies of residual leukemic cells of these 196 patients were assessed in 267 follow-up bone marrow samples using immunophenotypic assessment of minimal residual disease.

Results

The median frequency of residual leukemic cells after the first cycle of chemotherapy was 8.5-fold higher in patients with FLT3-ITD than in those with wild type FLT3. Such a difference translates into differences in survival, even if other potentially outcome-modulating mutations, such as NPM1, KIT, NRAS, KRAS, FLT3-exon 20 and PTPN11 are included in the analysis.

Conclusions

This study shows that it could be possible to study the efficacy of FLT3 inhibitors using the level of minimal residual disease as a short-term end-point.     

Patient-specific microRNA expression profiles as a marker for minimal residual disease in acute myeloid leukemia

MicroRNAs are a class of small noncoding RNAs playing a crucial role in physiological and pathological conditions, including acute myeloid leukemia. We aimed at examining whether in clinical settings the identification of patient-specific leukemia-associated profiles (LAMPs) of overexpressed microRNAs could be used for minimal residual disease (MRD) detection. Patients with identified LAMPs at diagnosis were further tested for the presence of LAMP after induction therapy. Those with identifiable MRD defined by LAMP expression after induction showed a trend toward a shorter overall survival. Larger studies are needed to confirm the utility of patient-specific LAMPs for MRD follow-up.     

Aberrant promoter CpG methylation as a molecular marker for disease monitoring in natural killer cell lymphomas

Natural killer (NK) cell lymphomas lack suitable clonal markers for tumour cell detection, making the monitoring of minimal residual lymphoma difficult. Aberrant promoter CpG methylation occurs frequently in NK cell lymphomas. The objective of this study was to assess the potential of aberrant methylation as a surrogate tumour marker. Twenty-five primary tumours and 105 serial biopsies taken at various time points after treatment were examined using a methylation-specific polymerase chain reaction (MSP) for a panel of genes, comprising p73, p16, hMLH1, RARbeta and p15, previously shown to be methylated in NK cell lymphomas. All samples underwent independent morphological examination, supplemented by immunostaining for CD56 and in-situ hybridization for Epstein-Barr-virus-encoded RNA. Primary tumours showed the frequent methylation of the genes p73 (92%), p16 (71%), hMLH1 (61%), RARbeta (56%) and p15 (48%). MSP results in serial post-treatment biopsies were correlated with clinicopathological findings. Results were concordant in 89 follow-up samples (18 samples, histology positive/MSP positive; 71 samples, histology negative/MSP negative) and discordant in 16. Fifteen samples were histology negative/MSP positive, and tumour involvement was subsequently confirmed (positive re-biopsies or relapses at the same sites), indicating that MSP was more sensitive for minimal lymphoma detection. One sample was histology positive/MSP negative; a subsequent histological review and continuous clinical remission of the patient did not support tumour involvement. Our findings suggest that MSP for aberrantly methylated genes is a potentially valuable molecular marker for detecting either residual or relapsed disease in NK cell lymphoma patients.     

Rituximab as treatment for minimal residual disease in hairy cell leukaemia

Abstract:  Purine analogues have dramatically improved the outcome of patients affected by hairy cell leukemia (HCL), although complete eradication of disease was achieved in few cases. The purpose of this study was to evaluate the role of Rituximab in eradicating minimal residual disease (MRD) in HCL patients after a pre-treatment with 2-chloro-deoxy-adenosine (2-CdA). Ten patients received four cycles of Rituximab after administration of Cladribrine. Before starting anti-CD20 antibody, two patients were in complete remission, six in partial remission and two showed no significant response to Cladribrine. All cases resulted IgH-positive. Median time from the last 2-CdA infusion was 5.7 months. Eight of 10 patients [four in partial remission (PR), two in complete remission (CR) and two unresponsive after 2-CdA] were evaluable for response. Two months after the end of anti-CD20 therapy, all evaluated patients presented a complete haematological remission. Moreover, Rituximab increased percentage of molecular remission up to 100% 1 yr after the end of treatment. Interestingly, in all cases but one, including those persistently polymerase chain reaction (PCR)-positive, semi-quantitative molecular analyses showed MRD levels lower than those found before Rituximab administration. Toxicity was very mild. The present results not only confirm the therapeutic effect of Rituximab, but also show its relevance in eradicating MRD in HCL.