Systemic mastocytosis associated with t(8;21)(q22;q22) acute myeloid leukemia

Although KIT mutations are present in 20–25% of cases of t(8;21)(q22;q22) acute myeloid leukemia (AML), concurrent development of systemic mastocytosis (SM) is exceedingly rare. We examined the clinicopathologic features of SM associated with t(8;21)(q22;q22) AML in ten patients (six from our institutions and four from published literature) with t(8;21) AML and SM. In the majority of these cases, a definitive diagnosis of SM was made after chemotherapy, when the mast cell infiltrates were prominent. Deletion 9q was an additional cytogenetic abnormality in four cases. Four of the ten patients failed to achieve remission after standard chemotherapy and seven of the ten patients have died of AML. In the two patients who achieved durable remission after allogeneic hematopoietic stem cell transplant, recipient-derived neoplastic bone marrow mast cells persisted despite leukemic remission. SM associated with t(8;21) AML carries a dismal prognosis; therefore, detection of concurrent SM at diagnosis of t(8;21) AML has important prognostic implications

Secondary cytogenetic abnormalities in core-binding factor AML harboring inv(16) vs t(8;21)

Patients with core-binding factor (CBF) acute myeloid leukemia (AML), caused by either t(8; 21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22), have higher complete remission rates and longer survival than patients with other subtypes of AML. However, similar to 40% of patients relapse, and the literature suggests that patients with inv(16) fare differently from those with t(8;21). We retrospectively analyzed 537 patients with CBF-AML, focusing on additional cytogenetic aberrations to examine their impact on clinical outcomes. Trisomies of chromosomes 8, 21, or 22 were significantly more common in patients with inv(16)/t(16;16): 16% vs 7%, 6% vs 0%, and 17% vs 0%, respectively. In contrast, del(9q) and loss of a sex chromosome were more frequent in patients with t(8;21): 15% vs 0.4% for del(9q), 37% vs 0% for loss of X in females, and 44% vs 5% for loss of Y in males. Hyperdiploidy was more frequent in patients with inv(16) (25% vs 9%, whereas hypodiploidy was more frequent in patients with t(8;21) (37% vs 3%. In multivariable analyses (adjusted for age, white blood counts at diagnosis, and KIT mutation status), trisomy 8 was associated with improved overall survival (OS) in inv(16), whereas the presence of other chromosomal abnormalities (not trisomy 8) was associated with decreased OS. In patients with t(8;21), hypodiploidy was associated with improved disease-free survival; hyperdiploidy and del(9q) were associated with improved OS. KIT mutation (either positive or not tested, compared with negative) conferred poor prognoses in univariate analysis only in patients with t(8;21)

Bone marrow niche trafficking of miR-126 controls the self-renewal of leukemia stem cells in chronic myelogenous leukemia

Leukemia stem cells (LSCs) in individuals with chronic myelogenous leukemia (CML) (hereafter referred to as CML LSCs) are responsible for initiating and maintaining clonal hematopoiesis. These cells persist in the bone marrow (BM) despite effective inhibition of BCR–ABL kinase activity by tyrosine kinase inhibitors (TKIs). Here we show that although the microRNA (miRNA) miR-126 supported the quiescence, self-renewal and engraftment capacity of CML LSCs, miR-126 levels were lower in CML LSCs than in long-term hematopoietic stem cells (LT-HSCs) from healthy individuals. Downregulation of miR-126 levels in CML LSCs was due to phosphorylation of Sprouty-related EVH1-domain-containing 1 (SPRED1) by BCR–ABL, which led to inhibition of the RAN–exportin-5–RCC1 complex that mediates miRNA maturation. Endothelial cells (ECs) in the BM supply miR-126 to CML LSCs to support quiescence and leukemia growth, as shown using mouse models of CML in which Mir126a (encoding miR-126) was conditionally knocked out in ECs and/or LSCs. Inhibition of BCR–ABL by TKI treatment caused an undesired increase in endogenous miR-126 levels, which enhanced LSC quiescence and persistence. Mir126a knockout in LSCs and/or ECs, or treatment with a miR-126 inhibitor that targets miR-126 expression in both LSCs and ECs, enhanced the in vivo anti-leukemic effects of TKI treatment and strongly diminished LSC leukemia-initiating capacity, providing a new strategy for the elimination of LSCs in individuals with CML

Core-binding factor acute myeloid leukemia with t(8;21) Risk factors and a novel scoring system (I-CBFit)

Background: Although the prognosis of core-binding factor (CBF) acute myeloid leukemia (AML) is better than other subtypes of AML, 30% of patients still relapse and may require allogeneic hematopoietic cell transplantation (alloHCT). However, there is no validated widely accepted scoring system to predict patient subsets with higher risk of relapse. Methods: Eleven centers in the US and Europe evaluated 247 patients with t(8;21) (q22;q22). Results: Complete remission (CR) rate was high (92.7%), yet relapse occurred in 27.1% of patients. A total of 24.7% of patients received alloHCT. The median diseasefree (DFS) and overall (OS) survival were 20.8 and 31.2 months, respectively. Age, KIT D816V mutated (11.3%) or nontested (36.4%) compared with KIT D816V wild type (52.5%), high white blood cell counts (WBC), and pseudodiploidy compared with hyper- or hypodiploidy were included in a scoring system (named I-CBFit). DFS rate at 2 years was 76% for patients with a low-risk I-CBFit score compared with 36% for those with a high-risk I-CBFit score (P <0.0001). Low- vs high-risk OS at 2 years was 89% vs 51% (P <0.0001). Conclusions: I-CBFit composed of readily available risk factors can be useful to tailor the therapy of patients, especially for whom alloHCT is not need in CR1 (ie, patients with a low-risk score)

Domino cyclization–alkylation protocol for the synthesis of 2,3-functionalized indoles from o-alkynylanilines and allylic alcohols

A practical and efficient protocol for the one-pot synthesis of 2,3-substituted indoles was developed via a palladacycle catalyzed domino cyclization–alkylation reaction involving 2-alkynylanilines and allylic alcohols under mild conditions without any additives