Detection of minimal residual disease in a patient having acute myelogenous leukemia with t(16;21)(p11;q22) treated by allogeneic bone marrow transplantation

TLS/FUS-ERG fusion gene in acute leukemia and myelodysplastic syndrome evolved to acute leukemia: report of six cases and a literature review

To investigate the pathogenesis and the refractory/relapse mechanisms in patients with t(16;21)(p11;q22), we retrospectively analyzed the clinical data of six cases in our hospital and sixty-two cases reported in the literature. Among the patients in our hospital, five cases were diagnosed as acute leukemia, and one was myelodysplastic syndrome evolved to acute myeloid leukemia, harboring TLS/FUS-ERG fusion gene; all the cases were detected t(16;21)(p11;q22) translocation, and five cases showed additional chromosomal abnormalities. We firstly report a novel three-way translocation t(11;16;21)(q13;p11;q22), which may affect the prognosis of leukemia with TLS-ERG fusion gene because this patient shows a more satisfactory treatment effect and deeper remission. And we found patients with TLS-ERG are more likely to have bone and arthrosis pain. Besides, CD56 and CD123 were positive in these cases, which are related to poor prognosis and the character of refractory. Moreover, some gene mutations are involved, and GATA2 and SMAD4 mutations were identified when the disease progressed from myelodysplastic syndrome to leukemia. Among sixty-two patients reported in the literature, valid positive percent of CD56 and CD123 were 81% and 14.3%, respectively. Mutation of the RUNX1 gene was detected in four cases, and one patient had multiple mutations, including BCOR, PLCG1, DIS3, BRAF, JAK2, and JAK3. The prominent feature of leukemia carrying the TLS/FUS-ERG gene is its poor prognosis. The relevant mechanism includes new mutation, jumping translocation, different transcripts, and so on. The mechanism still acquaints scarcely, which requires further study.

Outcome and Minimal Residual Disease Monitoring in Patients with t(16;21) Acute Myelogenous Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Patients with t(16;21) acute myelogenous leukemia (AML) who receive chemotherapy have poor outcomes. The treatment efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) must be identified, and the usefulness of minimal residual disease (MRD) monitoring requires evaluation. Fourteen consecutive patients with t(16;21) AML undergoing allo-HSCT at our institution were included in this study. Translocation liposarcoma- ETS-related gene (TLS-ERG) transcript levels were serially monitored for a median of 15 months (range, 3-51 months) after allo-HSCT. Eight patients relapsed, 7 patients died from relapse-related causes, and 1 patient died from a non-relapse-related cause. The 2-year cumulative incidence rates of relapse, disease-free survival, and overall survival after HSCT were 66.2%, 30.8%, and 46.2%, respectively. Of the 3 patients who received an HLA-matched sibling transplant, 2 relapsed, and 1 (33.3%) was in hematologic complete remission (CR) but died of nonrelapse mortality, whereas 5 of 11 patients (45.5%) who received haploidentical transplantation were in CR and were alive. Two of 6 patients with undetectable TLS-ERG at the time of allo-HSCT relapsed, at 14 and 15 months, and 3 of 4 PCR-positive patients relapsed, at a median of 10 months after HSCT. Four patients with continually low post-HSCT TLS-ERG levels (mostly <.01%) remained alive and in CR. The TLS-ERG levels of all 8 patients who relapsed were significantly increased before the relapse, exceeding 1.0% in all 7 patients who experienced hematologic relapse. In total, 7 patients received modified donor lymphocyte infusion (DLI), and 1 patient received IFN-α. All 7 patients with a TLS-ERG level >5.0% at the time of intervention experienced an increase or a brief decrease in TLS-ERG level, followed by an increase, and 6 relapsed, whereas the TLS-ERG level of 1 patient with a TLS-ERG level <1.0% at intervention decreased to undetectable. Therefore, t(16;21) AML is an indication for allo-HSCT. Among the HSCT recipients, 30.8% responded to treatment with CR. TLS-ERG transcript levels reflect MRD and might predict relapse and guide effective intervention.

[Clinical characteristics of acute myeloid leukemia with t (16;21) (p11;q22):nine cases report and literature review]

目的

探讨t(16;21）（p11；q22）急性髓系白血病（AML）的生物学及临床特征、疗效及预后。

方法

回顾性分析2009年1月至2014年12月北京大学人民医院收治的9例初诊t(16;21）（p11；q22）AML患者临床资料，并汇总国外文献报道的42例患者，采用Kaplan-Meier法进行生存分析。

结果

9例t(16;21）（p11；q22) AML占同期AML患者的0.66%。9例患者中，男4例，女5例。FAB分型：M₁ 1例、M₂ 5例、M₄ 1例、M₅ 2例；其中3例在诊断时形态学可见空泡形成。免疫表型除表达髓系CD117、CD13、CD33及CD34外，均表达CD56。染色体G显带分析均可见t(16;21）（p11；q22），5例伴有复杂核型。所有患者均可检测到TLS/FUS-ERG融合基因。9例化疗后均获完全缓解（CR）。2例仅接受化疗的患者分别于诊断后5和16个月复发，并于10和27个月死亡。7例于缓解后接受异基因造血干细胞移植（allo-HSCT），中位生存21(11~46）个月。汇总文献报道的42例成人t(16;21）（p11;q22）AML患者，其中单纯化疗组27例，HSCT组15例，两组患者中位生存期分别为10(95% CI 1~17）个月及18(95% CI 2~76）个月，差异有统计学意义（P<0. 001）。

结论

t(16;21）（p11；q22) AML是一类少见的AML，其具有特殊的形态学及免疫表型特点，总体预后差，allo-HSCT治疗可改善其预后，推荐首次CR后行allo-HSCT治疗。

Relapse of Acute Myeloid Leukemia with t(16;21)(p11;q22) Mimicking Autoimmune Pancreatitis after Second Allogeneic Bone Marrow Transplantation

We report the case of a 37-year-old woman who had a relapse of acute myeloid leukemia (AML) during treatment for chronic graft versus host disease (cGVHD) after allogeneic bone marrow transplantation. She was originally suspected of having autoimmune pancreatitis. Relapse of AML often occurs at extramedullary sites. Whereas the pancreas is rare as an organ of AML relapse, physicians should be aware that enlargement of the pancreas could be a sign of relapsed AML when excluding autoimmune pancreatitis, particularly during active cGVHD after allogeneic stem cell transplantation.

TLS/FUS-ERGfusion gene in acute lymphoblastic leukemia with t(16;21)(p11;q22) and monitoring of minimal residual disease

This study reports a 1-year-old boy with precursor B cell acute lymphoblastic leukemia (ALL) carrying t(16;21)(p11;q22). Reverse transcriptase-polymerase chain reaction (RT-PCR) and direct sequence analysis showed TLS/FUS-ERG chimeric mRNA with a novel junctional pattern of exon 7 of TLS/FUS and exon 6 of ERG. He did not respond to ALL-oriented therapy. Complete remission (CR) was achieved by chemotherapy oriented for acute myeloid leukemia. Allogenic bone marrow transplantation was done and he has been in CR for 24 months. TLS/FUS-ERG chimeric mRNA was not detected after CR. This is the first report of an ALL patient with a TLS/FUS-ERG fusion transcript.

Molecular prognostic markers for adult acute myeloid leukemia with normal cytogenetics

Acute myeloid leukemia (AML) is a heterogenous disorder that results from a block in the differentiation of hematopoietic progenitor cells along with uncontrolled proliferation. In approximately 60% of cases, specific recurrent chromosomal aberrations can be identified by modern cytogenetic techniques. This cytogenetic information is the single most important tool to classify patients at their initial diagnosis into three prognostic categories: favorable, intermediate, and poor risk. Currently, favorable risk AML patients are usually treated with contemporary chemotherapy while poor risk AML patients receive allogeneic stem cell transplantation if suitable stem cell donors exist. The largest subgroup of AML patients (aproximately 40%) have no identifiable cytogenetic abnormalities and are classified as intermediate risk. The optimal therapeutic strategies for these patients are still largely unclear. Recently, it is becoming increasingly evident that it is possible to identify a subgroup of poorer risk patients among those with normal cytogenic AML (NC-AML). Molecular risk stratification for NC-AML patients may be possible due to mutations of NPM1, FLT3, MLL, and CEBPalpha as well as alterations in expression levels of BAALC, MN1, ERG, and AF1q. Further prospective studies are needed to confirm if poorer risk NC-AML patients have improved clinical outcomes after more aggressive therapy.

Extramedullary sites of leukemia relapse after transplant

Recurrent or residual leukemia found in extramedullary sites after intensive treatments adversely affects prognosis. To summarize the sites and outcomes when extramedullary relapses have been reported after stem cell transplants, and to elucidate when long survival has been achieved, 207 cases were analysed. Authors were contacted for follow-up information. The most commonly reported sites are soft tissue in acute leukemias and bone in CML. Extramedullary relapse occurred typically within 2 years in ALL, but later in one-third of myeloid leukemias. Most testicular relapses reported in AML followed non-TBI conditioning. Marrow relapse was not inevitable if aggressive treatment was begun early. Local therapy alone was generally inadequate. Intensive therapy has produced lengthy remissions in cases of acute leukemias involving various sites, whereas CML cases, particularly involving bone, were most resistant to treatment. Heightened awareness and aggressive treatment should improve the prospect for cure after extramedullary relapse.

Detection of minimal residual disease in acute myelogenous leukemia

Acute myelogenous leukemia (AML) is considered to be in complete remission when fewer than 5% of the cells in bone marrow are blasts. Nevertheless, approximately two thirds of patients relapse due to persisting leukemic blasts. The persistence of these cells, below the threshold of morphological detection, is termed minimal residual disease (MRD) and various methods are used for its detection. These methods include classical cytogenetics, fluorescence in situ hybridization, qualitative and quantitative RT-PCR and multiparametric flow cytometry. Currently, less than half of the AML patients have a specific marker detectable by RT-PCR techniques. The major specific molecular markers are involvement of the MLL gene with up to 50 different partners and partial tandem duplications, the core binding factor leukemias with AML1/ETO and CBFbeta/MYH11 rearrangements, PML/RARalpha in acute promyelocytic leukemia, internal tandem duplications and mutations of FLT3 and some other rare translocations. In addition, several other genes show abnormal expression levels in AML, including the Wilms tumor gene, the PRAME gene and Ig/TCR rearrangements. Most of these genetic abnormalities can be detected by qualitative but more importantly by quantitative RT-PCR. The kinetics of disappearance of molecular markers in AML differs between the various types of leukemias, although at least a 2 log reduction of transcript after induction chemotherapy is necessary for long-term remission in all types. Conversely, the change of PCR from negativity to positivity is highly predictive of relapse. Whereas in acute lymphoblastic leukemia, multiparametric flow cytometry is an established method for MRD detection, this is less so in AML. The reason is the absence of well-characterized leukemia-specific antigens and the existence of phenotypic changes at relapse. On the other hand, this method is convenient due to its simplicity and universal applicability. In conclusion, several methods can be used for MRD detection in AML patients; each has its pros and cons. Several issues still remain to be settled including the choice of the best method and the timing for MRD monitoring and above all the practical clinical implications of MRD in the various types of AML.

Minimal residual disease in acute myeloid leukaemia

Relapse remains the main cause of treatment failure in acute myeloid leukaemia (AML). Studies to date suggest that monitoring of minimal residual disease (MRD) in AML is useful in identifying patients at high risk of relapse from those in durable remission. This chapter describes the methodological advances in the detection of MRD and, in particular, focuses on the development of highly sensitive RT-PCR techniques, including real-time, for quantifying MRD. Preliminary results on the clinical utility of MRD monitoring in AML with t(8;21) and inv(16) are promising and provide the basis for further evaluation by quantitative real-time analysis in prospective clinical trials. For AML without a specific fusion transcript, the WT1 gene is an alternative molecular target. The clinical value of quantitative MRD monitoring in AML, however, will need to be confirmed in future studies.