Genetic landscape of ultra-stable chronic lymphocytic leukemia patients.

Background: Chronic lymphocytic leukemia (CLL) has a heterogeneous clinical course. Beside patients requiring immediate treatment, others show an initial indolent phase followed by progression and others do not progress for decades. The latter two subgroups usually display mutated IGHV genes and a favorable FISH profile. Patients and methods: Patients with absence of disease progression for over 10 years (10-34) from diagnosis were defined as ultra-stable CLL (US-CLL). Forty US-CLL underwent extensive characterization including whole exome sequencing (WES), ultra-deep sequencing and copy number aberration (CNA) analysis to define their unexplored genetic landscape. Microarray analysis, comparing US-CLL with non-US-CLL with similar immunogenetic features (mutated IGHV/favorable FISH), was also carried out to recognize US-CLL at diagnosis. Results: WES was carried out in 20 US-CLL and 84 non-silent somatic mutations in 78 genes were found. When re-tested in a validation cohort of 20 further US-CLL, no recurrent lesion was identified. No clonal mutations of NOTCH1, BIRC3, SF3B1 and TP53 were found, including ATM and other potential progression driving mutations. CNA analysis identified 31 lesions, none with known poor prognostic impact. No novel recurrent lesion was identified: most cases showed no lesions (38%) or an isolated del(13q) (31%). The expression of 6 genes, selected from a gene expression profile analysis by microarray and quantified by droplet digital PCR on a cohort of 79 CLL (58 US-CLL and 21 non-US-CLL), allowed to build a decision-tree capable of recognizing at diagnosis US-CLL patients. Conclusions: The genetic landscape of US-CLL is characterized by the absence of known unfavorable driver mutations/CNA and of novel recurrent genetic lesions. Among CLL patients with favorable immunogenetics, a decision-tree based on the expression of 6 genes may identify at diagnosis patients who are likely to maintain an indolent disease for decades.

The microRNA-26a target E2F7 sustains cell proliferation and inhibits monocytic differentiation of acute myeloid leukemia cells.

Blocks in genetic programs required for terminal myeloid differentiation and aberrant proliferation characterize acute myeloid leukemia (AML) cells. 1,25-Dihydroxy-vitamin D3 (VitD3) arrests proliferation of AML cells and induces their differentiation into mature monocytes. In a previous study, we showed that miR-26a was induced upon VitD3-mediated monocytic differentiation. Here, we identify E2F7 as a novel target of miR-26a. We show that E2F7 significantly promotes cell cycle progression and inhibits monocytic differentiation of AML cells. We also demonstrate that E2F7 binds the cyclin-dependent kinase inhibitor p21(CIP1/WAF1) (cyclin-dependent kinase inhibitor 1A) promoter repressing its expression. Moreover, interfering with E2F7 expression results in inhibition of c-Myc (v-myc myelocytomatosis viral oncogene homolog) transcriptional activity. This leads to the downregulation of c-Myc transcriptional target miR-17-92 cluster, whose expression has a well-defined role in contributing to block monocytic differentiation and sustain AML cell proliferation. Finally, we show that the expression of E2F7 is upregulated in primary blasts from AML patients. Thus, these findings indicate that the newly identified miR-26a target E2F7 might have an important role in monocytic differentiation and leukemogenesis.

The genome of chemorefractory chronic lymphocytic leukemia reveals frequent mutations of NOTCH1 and SF3B1.

Next-generation whole-exome sequencing has revealed two novel genes, namely NOTCH1 and SF3B1, whose mutations predict poor outcome and preferentially associate with chemorefractory chronic lymphocytic leukemia (CLL). Analysis of 539 CLL cases documents that NOTCH1 mutations i) represent one of the most frequent cancer gene mutations involved at presentation; ii) cluster with cases harboring trisomy 12 and tend to be mutually exclusive with TP53 disruption among genetic subgroups; iii) identify high-risk patients showing poor survival similar to that associated with TP53 abnormalities; and iv) exert a prognostic role independent of widely accepted clinical and genetic risk factors. Mutations of SF3B1, a splicing factor that is a critical component of the spliceosome, recurrently associate with fludarabine-refractory CLL, occur at a low rate at CLL presentation and have a minor role in Richter transformation, corroborating the notion that CLL histological shift is molecularly distinct from chemorefractory progression without the Richter transformation.

Different isoforms of the B-cell mutator activation-induced cytidine deaminase are aberrantly expressed in BCR-ABL1-positive acute lymphoblastic leukemia patients.

The main reason for the unfavorable clinical outcome of BCR-ABL1-positive acute lymphoblastic leukemia (ALL) is genetic instability. However, how normal B-cell precursors acquire the genetic changes that lead to transformation has not yet been completely defined. We investigated the expression of the activation-induced cytidine deaminase (AID) and its role in clinical outcome in 61 adult BCR-ABL1-positive ALL patients. AID expression was detected in 36 patients (59%); it correlated with the BCR-ABL1 transcript levels and disappeared after treatment with tyrosine kinase inhibitors. Different AID splice variants were identified: full-length isoform; AIDDeltaE4a, with a 30-bp deletion of exon 4; AIDDeltaE4, with the exon 4 deletion; AIDins3, with the retention of intron 3; AIDDeltaE3-E4 isoform without deaminase activity. AID-FL predominantly showed cytoplasmic localization, as did the AID-DeltaE4a and AID-DeltaE3E4 variants, whereas the C-terminal-truncated AID-DeltaE4 showed a slightly increased nuclear localization pattern. AID expression correlated with a higher number of copy number alterations identified in genome-wide analysis using a single-nucleotide polymorphism array. However, the expression of AID at diagnosis was not associated with a worse prognosis. In conclusion, BCR-ABL1-positive ALL cells aberrantly express different isoforms of AID that may act as mutators outside the immunoglobulin (Ig) gene loci in promoting genetic instability.

Improving the procedure for detection of intrahepatic transplanted islets by magnetic resonance imaging.

Islet transplantation is an effective therapy for restoring normoglycemia in type-1 diabetes, but long-term islet graft function is achieved only in a minority of cases. Noninvasive magnetic resonance imaging of pancreatic islets is an attractive option for "real-time" monitoring of graft evolution. So far, previous studies have been performed in the absence of a standardized labeling procedure and, besides a feasibility study in patients, the effectiveness and safety of various labeling approaches were tested only with high field magnets (4.7 T). In this study, we addressed: (a) standardization of a labeling procedure for human islets with clinically-approved contrast agent Endorem, (b) safety aspects of labeling related to inflammation and (c) quality of imaging both at 7 T and 1.5 T. We have highlighted that the ratio of Endorem/islet is crucial for reproducible labeling, with a ratio of 2.24 ug/IEQ, allowing successful in vivo imaging both with 1.5 T and 7.0 T magnets up to 143 days after intrahepatic transplant. With this standardized labeling procedure, labeled islets are neither inflamed nor more susceptible to inflammatory insults than unlabeled ones. This report represents an important contribution towards the development of a standardized and safe clinical protocol for the noninvasive imaging of transplanted islets in humans.

A single high dose of idarubicin combined with high-dose ABA-C (MSKCC ALL-3 protocol) in adult and pediatric patients with acute lymphoblastic leukemia. Experience at the University La Sapienza of Rome.

BACKGROUND AND OBJECTIVE: The anthracycline analogue idarubicin, either alone or in combination with other antineoplastic drugs, has shown antileukemic activity in relapsed and refractory acute lymphoblastic leukemia (ALL). In an attempt to minimize the non-hematologic toxicity and obtain a potent antileukemic effect, MSKCC activated a pilot study in previously treated adult ALL, using HD-ARA-C combined with idarubicin administered as a single high-dose infusion. We herein report our experience with a series of pediatric and adult high risk ALL and NHL patients treated with the protocol above, which confirms its feasibility, response rate and individual compliance. METHODS: In a clinical phase II study the combination of a single high dose (HD) idarubicin and HD cytosine-arabinoside (ARA-C), as designed at the Memorial Sloan Kettering Cancer Center, was applied to 70 adults and children with refractory or early relapse acute lymphoblastic leukemia (ALL) and T-cell lymphoblastic non-Hodgkin's lymphoma (NHL). Therapy consisted of HD-ARA-C 3 g/m2/d on days 1-5, idarubicin 40 mg/m2 on day 3, prophylactic intrathecal methotrexate on days 1 and 4, and G-CSF 5 mg/kg/d s.c. from day 7 to hematopoietic reconstitution (PMN > 0.5 x 10(9)/L). RESULTS: Fifty-five of the 70 patients (78%) achieved complete remission (CR), four died in aplasia due to infection and 11 were non-responders. Recovery of blood counts occurred at a median of 21 days from the start of treatment. Non-hematologic side effects were extremely limited and consisted predominantly of infections. INTERPRETATION AND CONCLUSIONS: In view of the highly unfavorable series of patients selected, this study confirms the feasibility and antileukemic activity of the HD-idarubicin + HD- ARA-C combination in patients with refractory and early relapse ALL and NHL. The excellent tolerance to this regimen does not preclude bone marrow transplantation as post-remission treatment.

A single high dose of idarubicin combined with high-dose ARA-C (MSKCC ALL-3 protocol) in adult and pediatric patients with acute lymphoblastic leukemia. Experience at the University "La Sapienza" of Rome.

BACKGROUND AND OBJECTIVE: The anthracycline analogue idarubicin, either alone or in combination with other antineoplastic drugs, has shown antileukemic activity in relapsed and refractory acute lymphoblastic leukemia (ALL). In an attempt to minimize the non-hematologic toxicity and obtain a potent antileukemic effect, MSKCC activated a pilot study in previously treated adult ALL, using HD-ARA-C combined with idarubicin administered as a single high-dose infusion. We herein report our experience with a series of pediatric and adult high risk ALL and NHL patients treated with the protocol above, which confirms its feasibility, response rate and individual compliance. METHODS: In a clinical phase II study, the combination of a single high dose (HD) of idarubicin and HD cytosine-arabinoside (ARA-C), as designed at the Memorial Sloan Kettering Cancer Center, was applied to 70 adults and children with refractory or early relapse acute lymphoblastic leukemia (ALL) and T-cell lymphoblastic non-Hodgkin's lymphoma (NHL). Therapy consisted of HD-ARA-C 3 g/m2/d on days 1-5, idarubicin 40 mg/m2 on day 3, prophylactic intrathecal methotrexate on days 1 and 4, and G-CSF 5 mg/kg/d s.c. from day 7 to hematopoietic reconstitution (PMN > 0.5 x 10(9)/L). RESULTS: Fifty-five of the 70 patients (78%) achieved complete remission (CR), four died in aplasia due to infection and 11 were non-responders. Recovery of blood counts occurred at a median of 21 days from the start of treatment. Non-hematologic side effects were extremely limited and consisted predominantly of infections. INTERPRETATION AND CONCLUSIONS: In view of the highly unfavorable series of patients selected, this study confirms the feasibility and antileukemic activity of the HD-idarubicin + HD-ARA-C combination in patients with refractory and early relapse ALL and NHL. The excellent tolerance to this regimen does not preclude bone marrow transplantation as post-remission treatment.