Wy Au

Genomic analyses reveal global functional alterations that promote tumor growth and novel tumor suppressor genes in natural killer-cell malignancies

Natural killer (NK)-cell malignancies are among the most aggressive lymphoid neoplasms with very poor prognosis. We performed array comparative genomic hybridization analysis on a number of NK cell lines and primary tumors to gain better understanding of the pathogenesis and tumor biology of these malignancies. We also obtained transcriptional profiles of genes residing in these regions and compared them with normal and activated NK cells. Only 30–50% of the genes residing in the gained or deleted regions showed corresponding increased or decreased expression. However, many of the upregulated genes in regions of gain are functionally important for the proliferation and growth of the neoplastic population. Genes downregulated in regions of loss included many transcription factors or repressors, tumor suppressors or negative regulators of the cell cycle. The minimal common region of deletion in 6q21 included three known genes (PRDM1, ATG5 and AIM1) showing generally low expression. Mutations resulting in truncated PRDM1 and changes in conserved amino-acid sequences of AIM1 were detected. Highly methylated CpG islands 5′ of PRDM1 and AIM1 correlated with low expression of the transcripts. Reversal of methylation by Decitabine induced expression of PRDM1 and cell death. In conclusion, we have shown a general tumor-promoting effect of genetic alterations and have identified PRDM1 as the most likely target gene in del6q21. ATG5, an essential gene for autophagy and AIM1, a gene implicated in melanoma, may also participate in the functional abnormalities.

Natural killer cell lymphoma shares strikingly similar molecular features with a group of non-hepatosplenic γδ T-cell lymphoma and is highly sensitive to a novel aurora kinase A inhibitor in vitro

Natural killer (NK) cell lymphomas/leukemias are rare neoplasms with an aggressive clinical behavior. The majority of the cases belong to extranodal NK/T-cell lymphoma, nasal type (ENKTL) in the current WHO classification scheme. Gene-expression profiling (GEP) of 21 ENKTL and NK-cell lymphoma/leukemia patients, 17 NK- and T-cell lines and 5 indolent NK-cell large-granular-lymphocytic proliferation was performed and compared with 125 peripheral T-cell lymphoma (PTCL) patients previously studied. The molecular classifier derived for ENKTL patients was comprised of 84 transcripts with the majority of them contributed by the neoplastic NK cells. The classifier also identified a set of γδ-PTCLs both in the ENKTL cases as well as in cases initially classified as PTCL-not otherwise specified. These γδ-PTCLs expressed transcripts associated with the T-cell receptor (TCR)/CD3 complex, suggesting T cell rather than NK-cell lineage. They were very similar to NK-cell tumors by GEP, but were distinct from cytotoxic (αβ)-PTCL and hepatosplenic T-cell lymphoma, indicating derivation from an ontogenically and functionally distinct subset of γδ T cells. They showed distinct expression of Vγ9, Vδ2 transcripts and were positive for TCRγ, but negative for TCRβ by immunohistochemistry. Targeted inhibition of two oncogenic pathways (AURKA and NOTCH-1) by small-molecular inhibitors induced significant growth arrest in NK-cell lines, thus providing a rationale for clinical trials of these inhibitors in NK-cell malignancies.

Combined arsenic trioxide and all-trans retinoic acid treatment for acute promyelocytic leukaemia recurring from previous relapses successfully treated using arsenic trioxide.

Summary.  The optimal treatment of acute promyelocytic leukaemia (APL) recurring from relapses successfully treated using arsenic trioxide (As2O3) is undefined. Three APL patients relapsing from As2O3‐induced remission were studied. Re‐treatment with As2O3 failed in one patient in third relapse, and resulted in morphological but not molecular remission in another patient. Combination therapy with As2O3 and all‐trans retinoic acid (ATRA), however, resulted in morphological and molecular remission in all three cases, with a follow‐up time ranging from 6 to 16 months. Our results suggest a synergistic therapeutic effect between As2O3 and ATRA in APL in advanced relapse.

A20, ABIN-1/2 and CARD11 mutations and their prognostic value in gastrointestinal diffuse large B-cell lymphoma

Purpose: Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of aggressive lymphomas with the activated B-cell–like subtype characterized by constitutive NF-κB activation. Activating mutations of CARD11 and inactivating mutations of A20 are frequent events in DLBCL. However, the full extent of genetic alterations in the NF-κB pathway regulators and their potential prognostic value in DLBCL remain to be investigated. We investigated the genetic abnormalities of CARD11, A20, and ABIN-1/2/3 (the A20 binding inhibitor of NF-κB) and their clinicopathologic correlation in gastrointestinal DLBCL. Experimental Design: The somatic mutation and copy number changes of CARD11, A20, and ABIN-1/2/3 were investigated in 71 gastrointestinal DLBCLs by PCR/sequencing, and interphase FISH/array comparative genomic hybridization, respectively. The mutations identified were functionally characterized by NF-κB reporter assays and immunoprecipitation experiments. Results: Recurrent somatic mutations were found in CARD11 (10%), A20 (17%), ABIN-1 (4%), and ABIN-2 (3%), but not in ABIN-3. In comparison with the wild-type, all CARD11 mutants were potent NF-κB activators in vitro. On the basis of the destructive nature of the observed mutations, and the findings by reporter assays and immunoprecipitation studies, most if not all of the somatic mutations that were seen in A20, ABIN-1, and ABIN-2 could impair their normal functions. Among these genetic abnormalities, A20 somatic mutation was significantly associated with both poor overall survival and event-free survival. Conclusions: We show further evidence of NF-κB pathway genetic abnormalities in DLBCL, which are potentially valuable in the prognosis and design of future therapeutic strategies. Clin Cancer Res; 17(6); 1440–51. ©2011 AACR.

Extra-medullary relapse of leukemia following allogeneic bone marrow transplantation

The curative effect of allogeneic bone marrow transplantation (BMT) for acute and chronic leukemia is attributed to the intensive conditioning chemotherapy with or without radiotherapy, as well as an immune‐mediated graft versus leukemia (GVL) effect. A different pattern of relapse has been observed after allogeneic BMT for patients with leukemia. Compared with treatment using conventional chemotherapy alone, isolated extra‐medullary relapse of disease appears to be seen more commonly after allogeneic BMT. While a full donors hematopoiesis may be retained, prolonged morphological remission has been observed in the recipients bone marrow. There appears to be a population of leukemic cells with an affinity to extra‐medullary tissues. The failure of the leukemic clone to repopulate the recipients marrow suggests the presence of a more profound GVL effect in the marrow environment. The optimal treatment for extra‐medullary relapse of leukemia following allogeneic BMT remains uncertain. In the case of isolated extra‐medullary relapses following BMT, the leukemia may still be responsive to further treatment with chemotherapy and/or radiotherapy. The prognosis is poor in general, but prolonged survival has been observed in some of these patients. With the preservation of donors hematopoiesis in the recipients marrow, the use of intensive chemotherapy followed by donor lymphocyte or stem cell re‐infusion is a promising option. Copyright

Effects of Azithromycin in bronchiolitis obliterans syndrome after hematopoietic SCT—a randomized double-blinded placebo-controlled study

Bronchiolitis obliterans syndrome (BOS) is an important complication after hematopoietic SCT (HSCT). Recent observations suggested that azithromycin might improve lung function in BOS after HSCT. We conducted a randomized double-blinded placebo-controlled study on azithromycin in patients with BOS after HSCT. The treatment group (n=10) received oral azithromycin 250 mg daily while the control group (n=12) received placebo daily for 12 weeks. Respiratory symptoms were assessed by the St George Respiratory Questionnaires and spirometry at baseline (drug commencement), 1, 2, 3 (drug cessation) and 4 months (1 month after drug cessation). There was no significant difference in the baseline demographic characteristics between the treatment and the control groups in age, gender, time from HSCT to BOS, time since diagnosis of BOS, chronic GVHD, baseline respiratory symptom scores and baseline forced expiratory volume in 1 s (FEV1). Throughout and after 3 months of treatment, there were no significant changes in respiratory symptom scores and FEV1 measurements between the treatment and the control groups. In conclusion, there was no significant benefit of 3 months of oral azithromycin on the respiratory symptoms and lung function in patients with relatively late BOS after HSCT in this randomized placebo-controlled study.

Autoimmune thyroid dysfunction after hematopoietic stem cell transplantation

Summary:Autoimmune thyroid disease (AITD) may occur in patients after hematopoietic stem cell transplantation (HSCT). In all, 10 cases of AITD (seven allogeneic and three autologous HSCT) were diagnosed among 721 HSCT recipients, including two patients with sequential hyper- and hypothyroidism. The 5-year actuarial rates for AITD after allogeneic and autologous HSCT were 2.9 and 4%, respectively. Significant risk factors included HSCT for chronic myeloid leukemia, the HLA B46 and DR9 loci and the A2B46DR9 haplotype, while female donors showed trend to significance. On multivariate analysis, only female donors and HLA DR9 remained significant. For autologous HSCT, the associations with HLA B46 and DR9 were also significant. Only three donors had a family history of AITD. A review of other reported cases confirmed the predominance of female donors, although the other associations including graft-versus-host disease, familial AITD and other autoimmune phenomena might be related to reporting bias. Since the actuarial incidence of AITD from female donors with predisposing HLA alleles may be over 30%, susceptible recipients should be carefully monitored. Owing to the small number of reported cases and different HLA associations with AITD in different populations, our observations await confirmatory data from other registries.

Trisomy 21 as the sole acquired karyotypic abnormality in acute myeloid leukemia and myelodysplastic syndrome

We report five cases of myeloid disorders in which trisomy 21 (+21) was found as the sole acquired karyotypic abnormality, comprising two cases of acute myeloid leukemia (AML) and three cases of myelodysplastic syndrome (MDS). In this series, MDS patients with +21 presented as high grade disease, which included two cases of refractory anemia with excess of blasts (RAEB) and one case of refractory anemia with excess of blasts in transformation (RAEBt), and showed rapid disease progression. Significant thrombocytopenia was observed in all three patients, and bone marrow examination showed a marked reduction in megakaryocytes. AML patients with +21 included one case each of AML-M2 and M4. Despite the poor prognosis reported in AML patients with +21 as the sole abnormality, the patient in our series who was able to complete intensive treatment was cured of disease. The role of +21 in leukemogenesis is reviewed.

Aberrant p15 gene promoter methylation in therapy-related myelodysplastic syndrome and acute myeloid leukaemia: clinicopathological and karyotypic associations.

Summary. Seventeen patients with therapy‐related myelodysplastic syndrome/acute myeloid leukaemia (t‐MDS/AML) were examined for aberrant p15 gene methylation by methylation‐specific polymerase chain reaction. Ten patients (58%) showed p15 methylation, which was significantly related to monosomy/deletion of chromosome 7q, but not to antecedent chemotherapy, blast count, leukaemic evolution or survival. In three of six patients with marrow samples obtained prior to the diagnosis of t‐MDS/AML, p15 methylation predated disease development by up to 2 years. Bone marrow transplantation led to the disappearance of p15 methylation in one patient. These results showed that p15 methylation was an early event in the evolution of some t‐MDS/AML patients.

Risk of haematological malignancies in HLA-B27 carriers

Human leucocyte antigen (HLA)‐B27 carriers are predisposed to inflammatory and autoimmune diseases. Among 1137 patients with haematological diseases, 59 HLA‐B27 carriers were identified. Compared with 18 774 volunteers, the incidence of HLA‐B27 was increased in patients with acute leukaemia (relative risk RR = 1·67, P = 0·002), for both acute myeloid leukaemia (AML) (RR) = 1·67, P = 0·007) and acute lymphoblastic leukaemia (ALL) (RR = 1·68, P = 0·094). Of all the HLA‐B27 carriers, four patients had ankylosing spondylitis (AS), all with lymphoid malignancies (three ALL, one Hodgkins disease), whereas no HLA‐B27 carriers with myeloid leukaemia had AS symptoms (P = 0·006). This suggests that HLA‐B27 carriers may have an increased risk of acute leukaemia and those with concomitant AS may be predisposed to lymphoid malignancies.