Flavopiridol is a small molecule inhibitor of cyclin-dependent kinases (CDK) known to impair global transcription via inactivation of positive transcription elongation factor b. It has been demonstrated to have significant activity predominantly in chronic lymphocytic leukemia and acute myeloid leukemia in phase I/II clinical trials while other similar CDK inhibitors are vigorously being pursued in pre-clinical and clinical studies. Although flavopiridol is a potent therapeutic agent against blood diseases, some patients still have primary or acquired resistance throughout their clinical course. Considering the limited knowledge of resistance mechanisms of flavopiridol, we investigated the potential mechanisms of resistance to flavopiridol in a cell line system, which gradually acquired resistance to flavopiridol in vitro, and then confirmed the mechanism in patient samples. Herein, we present that this resistant cell line developed resistance through up-regulation of phosphorylation of RNA polymerase II C-terminal domain, activation of CDK9 kinase activity, and prolonged Mcl-1 stability to counter flavopiridol's drug actions. Further analyses suggest MAPK/ERK activation-mediated Mcl-1 stabilization contributes to the resistance and knockdown of Mcl-1 in part restores sensitivity to flavopiridol-induced cytotoxicity. Altogether, these findings demonstrate that CDK9 is the most relevant target of flavopiridol and provide avenues to improve the therapeutic strategies in blood malignancies.
Flavopiridol; Mcl-1; cyclin-dependent kinase 9 (CDK9); cyclin-dependent kinase (CDK) inhibitor; and leukemia
The inhibitor-of-apoptosis protein survivin, encoded by BIRC5, regulates apoptosis, cell division and proliferation. Several survivin splice variants have been described however, the prognostic significance of their expression has not been well defined in pediatric acute myeloid leukemia (AML).
Quantitative expression analyses of BIRC5 mRNA (n = 306) and survivin transcript splice variants (n = 90) were performed on diagnostic bone marrow samples from children with de novo AML treated on the clinical trials CCG-2961 and AAML03P1, then correlated with disease characteristics and clinical outcome.
Total BIRC5 expression did not correlate with clinical outcome. Fragment length analysis and sequencing of the entire BIRC5 transcript demonstrated three splice variants. The most prominent product, wild-type survivin, was expressed in all samples tested. Two minor transcripts were present in 90 patients treated on CCG-2961; survivin-2B and a novel variant, survivin-ΔEx2, characterized by deletion of BIRC5 exon II. A high 2B/ΔEx2 expression ratio (≥1) correlated with increased diagnostic WBC count, monocytic phenotype, +8 cytogenetics, lower complete remission (45% [n = 10] vs. 88% [n = 59], P < 0.001) and higher induction failure rates (23% [n = 5] vs. 3% [n = 2], P = 0.009). Consistent with this poor induction response, patients with a 2B/ΔEx2 ratio ≥1 had inferior 5-year survival rates (OS 36% vs. 60%, P = 0.011; EFS 23% vs. 53% at 5 years, P = 0.001) and appear to have increased relapse risk (P = 0.056). Subset analyses suggest that relative over-expression of 2B, rather than under-expression of ΔEx2 determines clinical response.
High survivin-2B/ΔEx2 ratios are associated with refractory disease and inferior survival in childhood AML. Survivin splice variant expression warrants prospective evaluation in clinical trials.
Survivin; splice variant; acute myeloid leukemia; childhood AML; molecular genetics; refractory disease
Alemtuzumab consolidation has been investigated to improve remission duration after fludarabine-based induction for chronic lymphocytic leukemia (CLL). The impact on genomic high-risk disease remains unknown. CALGB 19901 and 10101 enrolled previously untreated patients to receive alemtuzumab consolidation after fludarabine-based induction. Immunoglobulin heavy chain gene mutation status (IGVH) and interphase cytogenetics were assessed retrospectively. Treatment response with these alemtuzumab-containing regimens was similar, regardless of genomic risk, except for patients harboring del(17p), where few complete remissions were observed. PFS was similar between IGVH groups, but OS was inferior in IGVH unmutated patients (P=0.03). Cytogenetic risk group was associated with PFS and OS (P=0.01 for both), with similarly short PFS in del(17p) and del(11q) and particularly short OS in del(17p) patients. Cytogenetic risk group remained signficantly associated with PFS and OS when controlling for other prognostic factors (PFS: P=0.009; OS: P=0.02), as did the negative association of IGVH unmutated disease with OS (P=0.004). Results were similar when restricting to patients who received at least one dose of alemtuzumab consolidation, demonstrating limited ability to overcome the poor outcome associated with high-risk genetic features.
CLL; alemtuzumab; clinical trial; cytogenetics; immunoglobulin genes
Infant leukemia (IL) is a rare sporadic cancer with a grim prognosis.
While most cases are accompanied by MLL-rearrangements and
harbor very few somatic mutations; less is known about the genetics of the cases
without MLL translocations. We performed the largest exome
sequencing study to date on matched non-cancer DNA from pairs of mothers and IL
patients to characterize congenital variation that may contribute to early
leukemogenesis. Using the COSMIC database to define acute leukemia-associated
candidate genes, we find a significant enrichment of rare, potentially
functional congenital variation in IL patients compared to randomly selected
genes within the same patients and unaffected pediatric controls. IL AML
patients had more overall variation than IL ALL patients, but less of that
variation was inherited from mothers. Of our candidate genes, we found that
MLL3 was a compound heterozygote in every infant who
developed AML and 50% of infants who developed ALL. These data suggest a
model by which known genetic mechanisms for leukemogenesis could be disrupted
without an abundance of somatic mutation or chromosomal rearrangements. This
model would be consistent with existing models for the establishment of leukemia
clones in utero and the high rate of IL concordance in
Infant; leukemia; exome; MLL3
Changes in gene dosage are a major driver of cancer, engineered from a finite, but increasingly well annotated, repertoire of mutational mechanisms1. This can potentially generate correlated copy number alterations across hundreds of linked genes, as exemplified by the 2% of childhood acute lymphoblastic leukemia (ALL) with recurrent amplification of megabase regions of chromosome 21 (iAMP21)2,3. We used genomic, cytogenetic and transcriptional analysis, coupled with novel bioinformatic approaches, to reconstruct the evolution of iAMP21 ALL. We find that individuals born with the rare constitutional Robertsonian translocation between chromosomes 15 and 21, rob(15;21)(q10;q10)c, have ~2700-fold increased risk of developing iAMP21 ALL compared to the general population. In such cases, amplification is initiated by a chromothripsis event involving both sister chromatids of the Robertsonian chromosome, a novel mechanism for cancer predisposition. In sporadic iAMP21, breakage-fusion-bridge cycles are typically the initiating event, often followed by chromothripsis. In both sporadic and rob(15;21)c-associated iAMP21, the final stages frequently involve duplications of the entire abnormal chromosome. The end-product is a derivative of chromosome 21 or the rob(15;21)c chromosome with gene dosage optimised for leukemic potential, showing constrained copy number levels over multiple linked genes. Thus, dicentric chromosomes may be an important precipitant of chromothripsis, as we show rob(15;21)c to be constitutionally dicentric and breakage-fusion-bridge cycles generate dicentric chromosomes somatically. Furthermore, our data illustrate that several cancer-specific mutational processes, applied sequentially, can co-ordinate to fashion copy number profiles over large genomic scales, incrementally refining the fitness benefits of aggregated gene dosage changes.
Five-year overall survival (OS) for children with B-cell precursor acute lymphoblastic leukemia (B-ALL) exceeds 90% with risk-adapted therapy. Age, initial WBC count, genetic aberrations, and minimal residual disease (MRD) are used for risk stratification. Intrachromosomal amplification of a region of chromosome 21 (iAMP21; three or more extra copies of RUNX1 on an abnormal chromosome 21) is a recently identified recurrent genomic lesion associated with inferior outcome in some studies. We investigated the impact of iAMP21 in a large cohort treated in contemporary Children's Oncology Group (COG) ALL trials.
Patients and Methods
Fluorescent in situ hybridization for specific genetic aberrations was required at diagnosis. MRD was measured by flow cytometry at end induction. Outcome was measured as event-free survival (EFS) and OS.
iAMP21 was found in 158 (2%) of 7,793 patients with B-ALL age ≥ 1 year; 74 (1.5%) of 5,057 standard-risk (SR) patients, and 84 (3.1%) of 2,736 high-risk (HR) patients. iAMP21 was associated with age ≥ 10 years, WBC less than 50,000/μL, female sex, and detectable MRD at day 29. Four-year EFS and OS were significantly worse for patients with iAMP21 and SR B-ALL, but iAMP21 was not a statistically significant prognostic factor in HR patients. There was no interaction between MRD and iAMP21. Among SR patients, day 29 MRD ≥ 0.01% and iAMP21 were associated with the poorest EFS and OS; absence of both was associated with the best outcome.
iAMP21 is associated with inferior outcome in pediatric B-ALL, particularly SR patients who require more intensive therapy and are now treated on HR COG ALL protocols.
Chemoimmunotherapy has led to improved numbers of patients achieving disease response, and longer overall survival in young patients with chronic lymphocytic leukaemia; however, its application in elderly patients has been restricted by substantial myelosuppression and infection. We aimed to assess safety and activity of ibrutinib, an orally administered covalent inhibitor of Bruton tyrosine kinase (BTK), in treatment-naive patients aged 65 years and older with chronic lymphocytic leukaemia.
In our open-label phase 1b/2 trial, we enrolled previously untreated patients at clinical sites in the USA. Eligible patients were aged at least 65 years, and had symptomatic chronic lymphocytic leukaemia or small lymphocytic lymphoma requiring therapy. Patients received 28 day cycles of once-daily ibrutinib 420 mg or ibrutinib 840 mg. The 840 mg dose was discontinued after enrolment had begun because comparable activity of the doses has been shown. The primary endpoint was the safety of the dose-fixed regimen in terms of frequency and severity of adverse events for all patients who received treatment. This study is registered with ClinicalTrials.gov, number NCT01105247.
Between May 20, 2010, and Dec 18, 2012, we enrolled 29 patients with chronic lymphocytic leukaemia and two patients with small lymphocytic lymphoma. Median age was 71 years (range 65–84), and 23 (74%) patients were at least 70 years old. Toxicity was mainly of mild-to-moderate severity (grade 1–2). 21 (68%) patients had diarrhoea (grade 1 in 14 [45%] patients, grade 2 in three [10%] patients, and grade 3 in four [13%] patients). 15 (48%) patients developed nausea (grade 1 in 12 [39%] patients and grade 2 in three [10%] patients). Ten (32%) patients developed fatigue (grade 1 in five [16%] patients, grade 2 in four [13%] patients, and grade 3 in one [3%] patient). Three (10%) patients developed grade 3 infections, although no grade 4 or 5 infections occurred. One patient developed grade 3 neutropenia, and one developed grade 4 thrombocytopenia. After a median follow-up of 22·1 months (IQR 18·4–23·2), 22 (71%) of 31 patients achieved an objective response (95% CI 52·0–85·8); four patients (13%) had a complete response, one patient (3%) had a nodular partial response, and 17 (55%) patients had a partial response.
The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or small lymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials.
Pharmacyclics, Leukemia and Lymphoma Society, D Warren Brown Foundation, Mr and Mrs Michael Thomas, Harry Mangurian Foundation, P50 CA140158 to Prof J C Byrd MD.
A causal role of gene amplification in tumorigenesis is well-known, while amplification of DNA regulatory elements as an oncogenic driver remains unclear. In this study, we integrated next-generation sequencing approaches to map distant estrogen response elements (DEREs) that remotely control transcription of target genes through chromatin proximity. Two densely mapped DERE regions located on chromosomes 17q23 and 20q13 were frequently amplified in ERα-positive luminal breast cancer. These aberrantly amplified DEREs deregulated target gene expression potentially linked to cancer development and tamoxifen resistance. Progressive accumulation of DERE copies was observed in normal breast progenitor cells chronically exposed to estrogenic chemicals. These findings may extend to other DNA regulatory elements, the amplification of which can profoundly alter target transcriptome during tumorigenesis.
Patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) have distinct clinical and biological features. Whereas most DS-ALL cases lack the sentinel cytogenetic lesions that guide risk assignment in childhood ALL, JAK2 mutations and CRLF2 overexpression are highly enriched. To further characterize the unique biology of DS-ALL, we performed genome-wide profiling of 58 DS-ALL and 68 non-Down syndrome (NDS) ALL cases by DNA copy number, loss of heterozygosity, gene expression, and methylation analyses. We report a novel deletion within the 6p22 histone gene cluster as significantly more frequent in DS-ALL, occurring in 11 DS (22%) and only two NDS cases (3.1%) (Fisher’s exact p = 0.002). Homozygous deletions yielded significantly lower histone expression levels, and were associated with higher methylation levels, distinct spatial localization of methylated promoters, and enrichment of highly methylated genes for specific pathways and transcription factor binding motifs. Gene expression profiling demonstrated heterogeneity of DS-ALL cases overall, with supervised analysis defining a 45-transcript signature associated with CRLF2 overexpression. Further characterization of pathways associated with histone deletions may identify opportunities for novel targeted interventions.
Down syndrome; acute lymphoblastic leukemia (ALL); histone; JAK2; CRLF2
Rituximab has modest activity in relapsed Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) but is associated with TNF-α release that can cause CLL proliferation and inhibit apoptosis. We examined whether disruption of TNF-α by etanercept improves response to rituximab in CLL. Eligible patients had previously treated CLL with performance status 0–3. Patients received etanercept 25 mg subcutaneously twice weekly (weeks 1–5) and rituximab 375 mg/m2 intravenously thrice weekly (weeks 2–5) using a phase I/II design. Primary endpoints were response and toxicity. The 36 enrolled patients had a median of 2 prior treatments; 50% were fludarabine-refractory, and 22% had del(17p13.1). Of the 34 response-evaluable patients, ten (29%) responded, including 9 partial responses and 1 complete remission. Response was not affected by prior rituximab nor fludarabine-refractory status, but no patients with del(17p13.1) responded. Median PFS for responders was 9.0 months (range 1–43). Ten patients have had treatment-free intervals exceeding 12 months, including four who have remained untreated for 32, 43, 46 and 56 months. Adverse events were mild, including mild infusion reactions, transient cytopenias and grade 3 infections in 14%. The combination of etanercept and thrice weekly rituximab produces durable remissions in non-del(17p13.1) CLL patients and is well tolerated.
Rituximab; Etanercept; chronic lymphocytic leukemia
Improvements in chemotherapy and medical support of patients treated with chemotherapy and radiation have led to an ever-increasing number of cancer survivors. Unfortunately, a small fraction of these patients develop secondary hematologic malignancies as a consequence of their exposure to genotoxic anti-cancer regimens. Most of these are myeloid malignancies, therapy-related acute myeloid leukemia (t-AML) or myelodysplasia (t-MDS); however, a small but growing body of literature exists, which describes therapy-related acute lymphoblastic leukemias (t-ALL). Nearly all these cases are reportedly associated with translocations involving chromosome 11q23, the site of the MLL gene. We herein report two cases of ALL occurring after chemotherapy for other malignancies that showed complex karyotypic abnormalities and distinct MLL amplification by fluorescence in situ hybridization analysis. Immunophenotypic analysis showed that both cases expressed a pro-B cell (CD10–) phenotype with aberrant myeloid antigen expression. Although MLL amplification has been reported in therapy-related myeloid disease, to our knowledge this is the first report of MLL amplification occurring in therapy-related B cell ALL.
Therapy-related ALL; MLL amplification
The genetic basis of hypodiploid acute lymphoblastic leukemia (ALL), a subtype of ALL characterized by aneuploidy and poor outcome, is unknown. Genomic profiling of 124 hypodiploid ALL cases, including whole genome and exome sequencing of 40 cases, identified two subtypes that differ in severity of aneuploidy, transcriptional profile and submicroscopic genetic alterations. Near haploid cases with 24–31 chromosomes harbor alterations targeting receptor tyrosine kinase- and Ras signaling (71%) and the lymphoid transcription factor IKZF3 (AIOLOS; 13%). In contrast, low hypodiploid ALL with 32–39 chromosomes are characterized by TP53 alterations (91.2%) which are commonly present in non-tumor cells, and alterations of IKZF2 (HELIOS; 53%) and RB1 (41%). Both near haploid and low hypodiploid tumors exhibit activation of Ras- and PI3K signaling pathways, and are sensitive to PI3K inhibitors, indicating that these drugs should be explored as a new therapeutic strategy for this aggressive form of leukemia.
The treatment of relapsed chronic lymphocytic leukemia (CLL) has resulted in few durable remissions. Bruton's tyrosine kinase (BTK), an essential component of B-cell–receptor signaling, mediates interactions with the tumor microenvironment and promotes the survival and proliferation of CLL cells.
We conducted a phase 1b–2 multicenter study to assess the safety, efficacy, pharmacokinetics, and pharmacodynamics of ibrutinib (PCI-32765), a first-in-class, oral covalent inhibitor of BTK designed for treatment of B-cell cancers, in patients with relapsed or refractory CLL or small lymphocytic lymphoma. A total of 85 patients, the majority of whom were considered to have high-risk disease, received ibrutinib orally once daily; 51 received 420 mg, and 34 received 840 mg.
Toxic effects were predominantly grade 1 or 2 and included transient diarrhea, fatigue, and upper respiratory tract infection; thus, patients could receive extended treatment with minimal hematologic toxic effects. The overall response rate was the same in the group that received 420 mg and the group that received 840 mg (71%), and an additional 20% and 15% of patients in the respective groups had a partial response with lymphocytosis. The response was independent of clinical and genomic risk factors present before treatment, including advanced-stage disease, the number of previous therapies, and the 17p13.1 deletion. At 26 months, the estimated progression-free survival rate was 75% and the rate of overall survival was 83%.
Ibrutinib was associated with a high frequency of durable remissions in patients with relapsed or refractory CLL and small lymphocytic lymphoma, including patients with high-risk genetic lesions. (Funded by Pharmacyclics and others; ClinicalTrials.gov number, NCT01105247.)
The mixed lineage leukemia (MLL) gene is commonly rearranged in infant leukemia (IL). Genetic determinants of susceptibility to IL are unknown. Recent genome wide association studies for childhood acute lymphoblastic leukemia (ALL) have identified susceptibility loci at IKZF1, ARID5B, and CEBPE.
We genotyped these loci in 171 infants with leukemia and 384 controls and evaluated associations overall, by subtype (ALL, acute myeloid leukemia (AML)), and by presence (+) or absence (−) of MLL rearrangements.
Homozygosity for a variant IKZF1 allele (rs11978267) increased risk of infant AML (Odds Ratio (OR)=3.9, 95% Confidence Interval (CI)=1.8–8.4); the increased risk was similar for AML/MLL+ and MLL− cases. In contrast, risk of ALL/MLL− was increased in infants homozygous for the IKZF1 variant (OR=5.1, 95%CI=1.8–14.5) but the variant did not modify risk of ALL/MLL+. For ARID5B (rs10821936), homozygosity for the variant allele increased risk for the ALL/MLL− subgroup only (OR=7.2, 95%CI=2.5–20.6). There was little evidence of an association with the CEBP variant (rs2239633).
IKZF1 is expressed in early hematopoiesis, including precursor myeloid cells. Our data provide the first evidence that IKZF1 modifies susceptibility to infant AML, irrespective of MLL rearrangements, and could provide important new etiologic insights into this rare and heterogeneous hematopoietic malignancy.
leukemia; genetic susceptibility; infants
The fragile histidine triad protein, Fhit, has a number of reported tumor suppressive functions which include signaling of apoptosis in cancer cells in vitro and in vivo, modulation of the DNA damage response, down-regulation of target oncogene expression, suppression of tumor growth in vivo, and suppression of cancer cell invasion and metastasis. Most of these functions of Fhit have been observed on exogenous re-expression of Fhit in Fhit-negative cancer cells. However, little is known about the tumorigenic changes that occur in normal or precancerous cells following loss of Fhit expression. Recently, we have shown that shortly after loss of Fhit expression, cells exhibit signs of DNA replication stress-induced DNA damage and develop genomic instability. Here, we extend these findings through investigation of different factors that affect Fhit function to prevent DNA damage. We found that Fhit activity is dependent upon a functional HIT domain and the tyrosine-114 residue, previously shown to be required for tumor suppression by Fhit. Furthermore, Fhit function was shown to be independent of exogenous and endogenous sources of oxidative stress. Finally, Fhit function was shown to be dependent upon Chk1 kinase activity, but independent of Atr or Atm kinases. Evidence suggests that Fhit and Chk1 kinase cooperate to prevent replication stress-induced DNA damage. These findings provide important and unexpected insights into the mechanism whereby loss of Fhit expression contributes to cell transformation.
The clinical significance of partial chromosome 3 alteration in uveal melanoma is still not clear. Also, the reported frequencies vary considerably in the published literature from 0 to 48%. The aims of the following study were to identify the frequency, molecular pathology and potential clinical significance of partial chromosome 3 alteration in uveal melanoma. We studied 47 uveal melanomas with an average follow-up of 36 months. Of these, 14 had confirmed metastasis. Allelic imbalance/loss of heterozygosity was studied using microsatellite markers on chromosome 3 enriched in markers located in the previously reported smallest regions of deletion overlap. Chromosomal alterations were assessed by conventional cytogenetics or comparative genomic hybridization (CGH) in a subset of patients. Utilizing genotyping, partial chromosome 3 alteration was detected in 14/47 tumors (30%). In the 23 tumors with available cytogenetic/CGH, partial chromosome 3 alteration was detected in 8/23 (38%) and was caused by both gains (4/8) and losses (4/8) of chromosome 3 with high frequency of complex chromosome 3 aberrations detected by cytogenetics. Out of the 14 tumors with confirmed metastasis, only 1 showed partial chromosome 3 alteration and the remaining showed monosomy 3. By limiting the aggressive disease marker to monosomy 3, genotyping showed 93% sensitivity and 67% specificity for detection of aggressive uveal melanoma. In conclusion, partial chromosome 3 alterations are common in uveal melanoma and mostly caused by complex cytogenetic changes leading to partial gains and/or partial losses of chromosome 3. Partial chromosome 3 alteration is not likely to be associated with highly aggressive uveal melanoma that metastasizes within the first 3 years after treatment. Microsatellite-based genotyping of chromosome 3 is highly sensitive for detection of aggressive uveal melanoma.
eye neoplasms; molecular genetics; uveal melanoma
To evaluate the prognostic significance of the international European LeukemiaNet (ELN) guidelines for reporting genetic alterations in acute myeloid leukemia (AML).
Patients and Methods
We analyzed 1,550 adults with primary AML, treated on Cancer and Leukemia Group B first-line trials, who had pretreatment cytogenetics and, for cytogenetically normal patients, mutational status of NPM1, CEBPA, and FLT3 available. We compared complete remission (CR) rates, disease-free survival (DFS), and overall survival (OS) among patients classified into the four ELN genetic groups (favorable, intermediate-I, intermediate-II, adverse) separately for 818 younger (age < 60 years) and 732 older (age ≥ 60 years) patients.
The percentages of younger versus older patients in the favorable (41% v 20%; P < .001), intermediate-II (19% v 30%; P < .001), and adverse (22% v 31%; P < .001) genetic groups differed. The favorable group had the best and the adverse group the worst CR rates, DFS, and OS in both age groups. Both intermediate groups had significantly worse outcomes than the favorable but better than the adverse group. Intermediate-I and intermediate-II groups in older patients had similar outcomes, whereas the intermediate-II group in younger patients had better OS but not better CR rates or DFS than the intermediate-I group. The prognostic significance of ELN classification was confirmed by multivariable analyses. For each ELN group, older patients had worse outcomes than younger patients.
The ELN classification clearly separates the genetic groups by outcome, supporting its use for risk stratification in clinical trials. Because they have different proportions of genetic alterations and outcomes, younger and older patients should be reported separately when using the ELN classification.
Studies of chronic lymphocytic leukemia (CLL) have yielded substantial progress, however a lack of immortalized cell lines representative of the primary disease has hampered a full understanding of disease pathogenesis and development of new treatments. Here we describe a novel CLL cell line (OSU-CLL) generated by EBV transformation, which displays a similar cytogenetic and immunophenotype observed in the patient’s CLL (CD5 positive with trisomy 12 and 19). A companion cell line was also generated from the same patient (OSU-NB). This cell line lacked typical CLL characteristics, and is likely derived from the patient’s normal B cells. In vitro migration assays demonstrated that OSU-CLL exhibits migratory properties similar to primary CLL cells whereas OSU-NB has significantly reduced ability to migrate spontaneously or towards chemokine. Microarray analysis demonstrated distinct gene expression patterns in the two cell lines, including genes on chromosomes 12 and 19, which is consistent with the cytogenetic profile in this cell line. Finally, OSU-CLL was readily transplantable into NOG mice, producing uniform engraftment by three weeks with leukemic cells detectable in the peripheral blood spleen and bone marrow. These studies describe a new CLL cell line that extends currently available models to study gene function in this disease.
Autologous stem cell transplant (ASCT) is an effective treatment for multiple myeloma (MM). However the timing of ASCT in the era of novel agents (lenalidomide, thalidomide, bortezomib) is unknown. We retrospectively reviewed the outcome of MM patients who received novel agent based induction treatment and received first ASCT within 12 months of diagnosis (early ASCT, N = 102), or at a later date (late ASCT, N = 65). Median time to ASCT was 7.9 months vs. 17.7 months in the early vs. late ASCT. The 3 and 5 yr overall Survival (OS) from diagnosis was 90 and 63% versus 82 and 63% in early and late ASCT respectively (P=0.45). Forty-one and 36 patients in the early and late ASCT have relapsed or progressed with median time to relapse of 28 and 23 mos (p=0.055). On multivariable analysis, factors predictive of increased risk for progression were ISS stage III (p=0.007), and < VGPR post-ASCT (p<0.001). Factor predictive of worst outcomes for OS was being on hemodialysis (p=0.037). No superiority of one agent was seen. In summary, early or late ASCT is a viable option for MM patients receiving induction treatment with novel targeted therapies.
Multiple Myeloma; Transplantation; Bortezomib; Lenalidomide
Five laboratories in the Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC) investigated standardizing and pooling of fluorescence in situ hybridization (FISH) results as a collaborative research project. This investigation used fixed bone marrow and blood cells available from previous conventional cytogenetic or FISH studies in two pilot studies, a one-day workshop, and proficiency test. Multiple FISH probe strategies were used to detect 6q-, 11q-, +12, 13q-, 17p-, and IGH rearrangements. Ten specimens were studied by participants who used their own probes (pilot study 1). Of 312 FISH interpretations, 224 (72%) were true-negative, 74 (24%) true-positive, 6 (2%) false-negative, and 8 (3%) false-positive. In pilot study no. 2, each participant studied two specimens using identical FISH probe sets to control for variation due to probe sets and probe strategies. Of 80 FISH interpretations, no false interpretations were identified. At a subsequent workshop, discussions produced agreement on scoring criteria. The proficiency test that followed produced no false-negative results and 4% (3/68) false-positive interpretations. Interpretation disagreements among laboratories were primarily attributable to inadequate normal cutoffs, inconsistent scoring criteria, and the use of different FISH probe strategies. Collaborative organizations that use pooled FISH results may wish to impose more conservative empiric normal cutoff values or use an equivocal range between the normal cutoff and the abnormal reference range to eliminate false-positive interpretations. False-negative results will still occur, and would be expected in low-percentage positive cases; these would likely have less clinical significance than false positive results. Individual laboratories can help by closely following rigorous quality assurance guidelines to ensure accurate and consistent FISH studies in their clinical practice and research.
The rare translocation t(8;14)(q11.2;q32) has been described in patients with B-cell acute lymphoblastic leukemia (ALL), particularly patients with Down Syndrome (DS).
We describe patients with t(8;14)(q11.2;q32) that were identified by the Children's Oncology Group (COG) ALL cytogenetics database, expanding our previous report of 10 patients with this translocation. Twenty-two such patients were treated with COG protocols. All patients had B-cell ALL and 7 (31.8%) had DS. None of the children with DS had an event, thus these patients had a superior estimated 5-year event-free survival (EFS) compared to non-DS patients (100% vs. 50.1 ± 17.7%; p=0.04). Only one patient (4.5%) had a concomitant Philadelphia chromosome t(9;22)(q34;q11.2). The cytogenetics data of two additional patients, who were not eligible for COG protocols, are also included in this report.
In conclusion, ALL patients with the recurring translocation t(8;14)(q11.2;q32) have B-cell phenotype and a high percentage have DS. Children with DS and t(8;14)(q11.2;q34) have improved event-free survival using standard COG therapy compared to non-DS patients. We did not find an increased number of patients with a concomitant Philadelphia chromosome in this population.
Acute Lymphoblastic Leukemia; B-cell; translocation; Down Syndrome
The impact of mutation of the ATM (ataxia telangiectasia mutated) gene in chronic lymphocytic leukemia (CLL) treatment outcome has not been examined. We studied ATM mutations in 73 patients treated with fludarabine and rituximab. ATM gene mutation analysis was performed using temperature gradient capillary electrophoresis. The impact of detected variants on overall survival (OS) and progression-free survival (PFS) was tested with proportional hazards models. None of the 73 patients demonstrated truncating ATM mutations; 17 (23%, 95% confidence interval 14 – 35%) had non-silent variants (ATM-NSVs), including 13 known ATM polymorphisms and four missense variants. ATM-NSVs were not significantly associated with any baseline characteristics including immunoglobulin heavy chain variable gene (IGVH) status. In multivariable models, no significant differences in complete response (p = 0.70), PFS (p = 0.59) or OS (p = 0.13) were observed. Our data indicate that truncating ATM mutations are rare in patients with CLL. Furthermore, in this dataset, these non-silent variants had limited impact on PFS and OS.
Chronic lymphocytic leukemia; ATM mutation; prognosis; chemoimmunotherapy
Complex karyotype (CK) on metaphase cytogenetics discriminates poor outcome in chronic lymphocytic leukaemia (CLL) patients undergoing salvage treatment; we hypothesized that it might provide prognostic information for patients undergoing allogeneic stem cell transplant. Fifty-one CLL patients were analysed following transplant; 18-month overall survival (OS), event-free survival (EFS) and cumulative incidence of progression estimates were 35%, 14% and 63%, respectively, in patients with CK (n = 19) versus 83%, 68% and 29% in patients without (n = 32) (P ≤ 0.0001, P ≤ 0.0001, and P = 0.02). In patients with high-risk interphase cytogenetics, CK remained predictive of worse OS (P = 0.02) and EFS (P = 0.009). These findings support further evaluation of metaphase karyotype in transplant risk assessment.
chronic lymphocytic leukaemia; transplant; fluorescent insitu hybridization; metaphase cytogenetics; conditioning