Dynamic prognostic value of the revised international prognostic scoring system following pretransplant hypomethylating treatment in myelodysplastic syndrome.

This study aimed to analyze the use of the revised International Prognostic Scoring System (IPSS-R) assessed after hypomethylating treatment (HMT) for patients with myelodysplastic syndrome (MDS) undergoing an allogeneic stem cell transplantation (SCT). Among 115 patients who received pre-SCT HMT, comparison analysis of the prognostic values between the IPSS-R at the time of HMT (IPSS-R@HMT) and at the time of SCT after HMT (IPSS-R@SCT) showed a significantly higher predictive power for overall survival (OS) of the latter. Alteration in IPSS-R risk occurred in 60%, while the patients with 'down-staged' IPSS-R@SCT showed better OS compared with those with 'unchanged' or 'up-staged' risk. On multivariate analysis in all 201 patients, IPSS-R@SCT, monosomal karyotype, treatment failure to pre-SCT treatment, and high hematopoietic cell transplantation-comorbidity index were independently associated with OS. Constructed using these factors, the MDS Transplantation Prognostic Scoring System (MTPSS) identified four risk groups with 4-year OS of 76.4% in low, 61.4% in intermediate-1 and 21.9% in intermediate-2 risk groups, whereas all in the high risk group died within 2 years after SCT (P<0.001). Our study emphasizes the need for further studies aiming to evaluate a transplantation prognostic model such as the MTPSS to make appropriate decisions for transplantation in MDS.

Comparable outcomes between younger (⩽40 years) and older (>40 years) adult patients with severe aplastic anemia after HLA-matched sibling stem cell transplantation using fludarabine-based conditioning.

Allogeneic stem cell transplantation from HLA-matched siblings (MSD-SCT) for elderly patients with severe aplastic anemia (SAA) is not a widely accepted first-line treatment. Recently, fludarabine, lower-dose cyclophosphamide and antithymocyte globulin conditioning (Flu/lower-dose Cy/ATG) with lower toxicities has been investigated. To determine whether this regimen can overcome the negative effects of age, we analyzed 117 adult patients with SAA who received MSD-SCT using Flu/lower-dose Cy/ATG, and compared outcomes between 63 younger age group (YAG; ⩽40 years) and 54 older age group (OAG; >40 years) patients. No primary graft failure was observed. Neutrophil engraftment was significantly faster in the YAG compared with the OAG (12 vs 13 days; P=0.04). The incidences of acute grade II-IV (9.5% vs 9.3% at day 100; P=0.42) and chronic GVHD (8.1% vs 9.5% at 5 years; P=0.80), secondary graft failure (20.8% vs 7.9% at 5 years; P=0.11) and transplant-related mortality (5.4% and 11.1% at 5 years; P=0.91) were not significantly different between the YAG and OAG. In addition, failure-free (73.7% vs 81.0% at 5 years; P=0.73) and overall survival rates (93.7% vs 88.9% at 5 years; P=0.20) were comparable. Our results suggest that MSD-SCT using Flu/lower-dose Cy/ATG may be a feasible first-line treatment even in older patients with SAA.

Impact of IKZF1 deletions on long-term outcomes of allo-SCT following imatinib-based chemotherapy in adult Philadelphia chromosome-positive ALL.

We investigated the prognostic relevance of IKZF1 deletions in 118 adult Ph-positive ALL patients who had minimal residual disease (MRD) data under a uniform treatment of allo-SCT following first-line imatinib-based chemotherapy. IKZF1 deletions were identified in 93 patients (78.8%). IKZF1-deleted patients had a lower proportion of early-stable molecular responders compared with wild-type patients (28.0 vs 56.0%, P=0.028). After a median follow-up of 72 months, IKZF1-deleted patients had a trend for higher cumulative incidence of relapse (CIR) (38.0 vs 13.3%, P=0.052), particularly in a subgroup of early-stable molecular responders (n=40; 21.4 vs 0%, P=0.088), but comparable disease-free survival to wild-type patients. Patients with biallelic-null deletions showed higher CIR (74.6 vs 13.3%, P=0.003) and lower disease-free survival (20.0 vs 67.5%, P=0.022) than wild-type patients. In multivariate analysis, MRD kinetics were closely related to outcomes, while neither IKZF1 deletions nor their functional subtypes retained an independent statistical power. Within the limitation of sample size, however, considering both the negative impact of IKZF1 deletions on MRD kinetics and a trend for relationship between IKZF1 deletions and relapse in early-stable molecular responders, IKZF1 deletions may have a potentially additive effect on unfavorable prognosis in a specific MRD-based subgroup of adult Ph-positive ALL transplants.

Identification of molecular and cytogenetic risk factors for unfavorable core-binding factor-positive adult AML with post-remission treatment outcome analysis including transplantation.

Emerging molecular studies have identified a subgroup of patients with unfavorable core-binding factor-positive (CBF)-AML who should be treated by intensified post-remission treatments. We analyzed 264 adults with CBF-AML from 2002 to 2011, and focused on 206 patients who achieved CR after standard '3+7' induction chemotherapy. Patients who achieved CR with an available donor were treated with allogeneic hematopoietic SCT (allo-HSCT, n=115) and the rest were treated with autologous (auto) HSCT (n=72) or chemotherapy alone (n=19). OS was not significantly different between CBFß/MYH11 (n=62) and RUNX1/RUNX1T1 (n=144), and auto-HSCT showed favorable OS compared with allo-HSCT or chemotherapy alone. Cytogenetic analysis identified that inv(16) without trisomy had a favorable OS and t(8;21) with additional chromosomes had an unfavorable OS, but multivariate analysis revealed those were NS. Patients with c-kit mutation showed inferior OS. For transplanted patients, residual post-transplant CBF-minimal residual disease quantitative PCR with higher WT1 expression at D+60 showed the worst OS with a higher incidence of relapse. Conclusively, we found that unfavorable CBF-AML can be defined with risk stratification using cytogenetic and molecular studies, and a careful risk-adapted treatment approach using frontline transplantation with novel therapies should be evaluated for this particular risk subgroup.

Merlin facilitates ubiquitination and degradation of transactivation-responsive RNA-binding protein.

The Nf2 tumor suppressor codes for merlin, a protein whose function is largely unknown. We have previously demonstrated a novel interaction between merlin and TRBP, which inhibits the oncogenic activity of TRBP. In spite of the significance of their functional interaction, its molecular mechanism still remains to be elucidated. In this report, we investigated how merlin inhibits the oncogenic activity of TRBP in association with cell growth conditions. In the human embryonic kidney 293 cell line, the level of endogenous merlin increased, whereas that of endogenous TRBP significantly decreased along with the increase in cell confluence. We demonstrated that the carboxyl-terminal region of TRBP was responsible for this phenomenon using stable cell lines expressing deletion mutants of TRBP. The overexpression of merlin decreased the protein level of TRBP, and the ubiquitin-like subdomain of merlin's FERM domain was important for this activity. We also demonstrated that TRBP is ubiquitinylated and the ubiquitinylated forms of TRBP are accumulated by ectopically expressed merlin or cell confluence in the presence of MG132, a proteasome inhibitor. Furthermore, we showed that the regulation of TRBP in response to cell confluence was abolished upon knockdown of merlin expression by specific small interfering RNA. Finally, we showed that ectopically expressed merlin restored cell-cell contact inhibition in cells stably expressing TRBP but not in TRBPDeltac. These results suggest that merlin is involved in the regulation of TRBP protein level by facilitating its ubiquitination in response to such cues as cell-cell contacts.