The CADM1 tumor suppressor gene is a major candidate gene in MDS with deletion of the long arm of chromosome 11.

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis leading to peripheral cytopenias and in a substantial proportion of cases to acute myeloid leukemia. The deletion of the long arm of chromosome 11, del(11q), is a rare but recurrent clonal event in MDS. Here, we detail the largest series of 113 cases of MDS and myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) harboring a del(11q) analyzed at clinical, cytological, cytogenetic, and molecular levels. Female predominance, a survival prognosis similar to other MDS, a low monocyte count, and dysmegakaryopoiesis were the specific clinical and cytological features of del(11q) MDS. In most cases, del(11q) was isolated, primary and interstitial encompassing the 11q22-23 region containing ATM, KMT2A, and CBL genes. The common deleted region at 11q23.2 is centered on an intergenic region between CADM1 (also known as Tumor Suppressor in Lung Cancer 1) and NXPE2. CADM1 was expressed in all myeloid cells analyzed in contrast to NXPE2. At the functional level, the deletion of Cadm1 in murine Lineage-Sca1+Kit+ cells modifies the lymphoid-to-myeloid ratio in bone marrow, although not altering their multilineage hematopoietic reconstitution potential after syngenic transplantation. Together with the frequent simultaneous deletions of KMT2A, ATM, and CBL and mutations of ASXL1, SF3B1, and CBL, we show that CADM1 may be important in the physiopathology of the del(11q) MDS, extending its role as tumor-suppressor gene from solid tumors to hematopoietic malignancies.

Poor prognosis of chromosome 7 clonal aberrations in Philadelphia-negative metaphases and relevance of potential underlying myelodysplastic features in chronic myeloid leukemia.

Clonal chromosome abnormalities in Philadelphia-negative cells could concern chronic myeloid leukemia patients treated by tyrosine kinase inhibitors. The European LeukemiaNet distinguishes -7/del(7q) abnormalities as a "warning". However, the impact of clonal chromosome abnormalities, and specifically those of -7/del(7q), in Philadelphia-negative cells on clinical outcomes is unclear and based on case-reports showing morphological dysplasia and increased risk of acute myeloid leukemia, suggesting the coexistence of chronic myeloid leukemia and high-risk myelodysplastic syndrome. The aim of this study was to determine whether the impact of -7/del(7q) clonal chromosome abnormalities in Philadelphia-negative cells on the clinical outcome is different from that of other types of abnormalities, and we argue for an underlying associated high-risk myelodysplastic syndrome. Among 102 chronic myeloid leukemia patients with clonal chromosome abnormalities in Philadelphia-negative cells with more than a median of 6 years of follow up, patients with -7/del(7q) more frequently had signs of dysplasia, a lower cumulative incidence of deep molecular response and often needed further treatment lines, with the consequent impact on event-free and progression-free survival. Morphological features of dysplasia are associated with myelodysplastic syndrome/acute myeloid leukemia mutations and compromise the optimal response to tyrosine kinase inhibitors, irrespectively of the type of clonal chromosome abnormalities in Philadelphia-negative cells. However, mutation patterns determined by next-generation sequencing could not clearly explain the underlying high-risk disease. We hereby confirm the pejorative prognostic value of -7/del(7q) clonal chromosome abnormalities in Philadelphia-negative cells and suggest that myelodysplastic features constitute a warning signal that response to tyrosine kinase inhibitors may be less than optimal.

Hyperdiploidy with 58-66 chromosomes in childhood B-acute lymphoblastic leukemia is highly curable: 58951 CLG-EORTC results.

The aim of our study was to analyze the factors contributing to heterogeneity of prognosis in patients with hyperdiploidy>50 chromosomes (HD>50), a group of B-cell precursor acute lymphoblastic leukemia with favorable outcome. The 541 HD>50 patients registered prospectively in the 58951 European Organisation for Research and Treatment of Cancer (EORTC) Children's Leukemia Group (CLG) trial, identified by karyotype (446 patients) and by DNA index (DI) (490 patients), had a 6-year event-free survival (EFS) of 89.0% (standard error [SE] = 1.5%) and a 6-year overall survival (OS) of 95.9% (SE = 0.9%). The strongest prognostic factor was the modal number of chromosomes (MNC): the 6-year EFS of 51-53, 54-57, and 58-66 MNC groups were 80%, 89%, and 99%, respectively (P < .0001). Ploidy assessed by DI was also a favorable factor: the higher the DI, the better the outcome. The 6-year EFS of the 3 subgroups of DI < 1.16/≥1.16-<1.24/≥1.24 were 83%, 90%, and 95%, respectively (P = .009). All usual combinations of trisomies (chromosomes 4, 10, 17, 18) were significant favorable factors but had lower EFS when MNC was lower than 58. In multivariate analysis, MNC remained the strongest factor. Consequently, the best indicator for excellent outcome was ploidy assessed by karyotype because patients with 58-66 chromosomes stood every chance of being cured (OS of 100% at 6-year follow-up) with less-intensive therapy. This trial was registered at www.clinicaltrials.gov as #NCT00003728. Registered: http://www.eortc.org/, http://clinicaltrials.gov/show/NCT00003728.

A cytogenetic study of 397 consecutive acute myeloid leukemia cases identified three with a t(7;21) associated with 5q abnormalities and exhibiting similar clinical and biological features, suggesting a new, rare acute myeloid leukemia entity.

The RUNX1 gene is implicated in numerous chromosomal translocations that occur in acute myeloid leukemia (AML) and result in chimeric genes. In this study, 397 consecutive AML cases were analyzed using RUNX1 fluorescence in situ hybridization (FISH) probes. Three cases of the recently described translocation, t(7;21)(p22;q22), were identified, which expressed RUNX1-USP42 (ubiquitin-specific protease 42) fusion transcripts, associated with 5q abnormalities and hyperploidy. These cases displayed homogeneous morphological features (including phagocytosis) and aberrantly expressed CD56 and CD7 lymphoid antigens. Although very few data are available from previously reported cases, when these features are present, a detailed chromosomal analysis, including hybridization with RUNX1 FISH probes, should be performed at diagnosis to recognize chromosomal abnormalities. Additional cases of t(7;21) positive AML should be evaluated to characterize this potentially rare AML entity in greater detail.

Chronic lymphocytic leukemia and prolymphocytic leukemia with MYC translocations: a subgroup with an aggressive disease course.

Translocations involving MYC are rare in chronic lymphocytic leukemia (CLL), and up to now, their prognostic significance remains unclear. We report the characteristics of 21 patients with CLL and nine patients with prolymphocytic leukemia (PLL), diagnosed in multiple centers (n = 13), which showed an MYC translocation demonstrated by fluorescence in situ hybridization. The prevalence was estimated to be <1%. Advanced age and male predominance were observed. Morphological analysis frequently revealed the presence of prolymphocytes. A typical "CLL-immunophenotype" was found in four of nine cases with PLL. Moreover, CD5 and CD23 were frequently expressed in PLL. The latter findings are atypical for PLL and may suggest transformation or progression of an underlying CLL. MYC translocations were frequently observed with concomitant adverse cytogenetic markers, such as del(11q) (n = 8/30) and/or del(17p)/monosomy 17 (n = 7/30). In addition, the presence of unbalanced translocations (n = 24 in 13/30 cases) and complex karyotype (n = 16/30) were frequent in cases with MYC translocations. Altogether, del(17p)/monosomy 17, del(11q), and/or complex karyotype were observed in 22 of 30 patients. Survival outcome was poor: the median time to treatment was only 5 months, and overall survival (OS) from clinical diagnosis and from genetic detection was 71 and 19 months, respectively. In conclusion, CLL/PLL with MYC translocations is a rare entity, which seems to be associated with adverse prognostic features and unfavorable outcome.

Specific chromosomal IG translocations have different prognoses in chronic lymphocytic leukemia.

BACKGROUND: Chromosomal translocations are usually analyzed as a single entity, and are associated with a poor outcome in chronic lymphocytic leukemia. Translocations involving immunoglobulin genes are recurrent, but uncommon (<5%), and their individual prognosis is not clear. The two most frequent partners are BCL2 (18q21) and BCL3 (19q13). DESIGNS AND METHODS: Herein, 75 cases are reported of chronic lymphocytic leukemia and t(14;18) (BCL2-CLLs). Our series benefits from morphological, immunological and cytogenetical reviews. The IGHV status analyses were performed by referring laboratories. Comparison was made with our previously published series of chronic lymphocytic leukemia patients with t(14;19) (BCL3-CLLs, n=29). RESULTS: Compared with BCL3-CLLs, lymphocytosis was lower in BCL2-CLLs (p<0.008), and splenomegaly was less frequent (p<0.0001). There were more "typical" morphologies (p<0.005) and Matutes scores >4 (p<0.001) in the BCL2-CLLs group, and less CD38 expression (p<0.04). More variant BCL2-translocations were observed (t(18;22), n=11; 2t(2;18), n=2; p<0.02), and BCL2-translocation was frequently single (p<0.002). Complex karyotypes (p<0.02), trisomy 12 (p<0.03), 6q deletion (p<0.002) and TP53 deletion (p<0.02) were less frequent in BCL2-CLLs, whereas 13q deletion was more frequent (p<0.005). The IGHV gene was frequently mutated in BCL2-CLLs (p<0.0001). Treatment-free survival was longer in BCL2-CLLs (p<0.0001). CONCLUSIONS: BCL2-CLL.S express CD5 and lack expression of CD38, and have a Matutes score ≥4, frequent trisomy 12, no ATM and 6q deletions, and a mutated IGHV status. Compared to BCL3-CLLs, BCL2-CLLs are much less aggressive; indicating that identifying individual translocations and cytogenetic partners would allow improved patient stratification.

NUP98-MLL fusion in human acute myeloblastic leukemia.

Posttranscriptional modifications of histones play important roles in the control of chromatin structure and transcription. H3K4 (histone H3 lysine 4) methylation by the SET domain of the trithorax-group protein MLL (mixed-lineage leukemia) is important for the control of homeobox (HOX) gene expression during development. MLL is tethered to the HOXA locus through interaction of its amino-terminus with menin. MLL fusion proteins associated with human leukemia contain the menin interaction peptide and frequently recruit H3K79 (histone H3 lysine 79) methylation activity. This allows sustained expression of HOXA genes important for cellular transformation. We have characterized a novel recurrent chromosomal aberration, inv(11)(p15q23), as an isolated chromosomal abnormality in 2 patients with acute myeloid leukemia. This aberration is predicted to result in the expression of an NUP98 (nucleoporin 98 kDa)-MLL fusion protein that is unable to interact with menin. As expected, low levels of HOXA gene expression were observed in the patients' samples. This fusion protein is predicted to participate in cellular transformation by activating MLL targets other than HOXA genes.

Loss of the Y chromosome in Philadelphia-positive cells predicts a poor response of chronic myeloid leukemia patients to imatinib mesylate therapy.

In chronic myeloid leukemia (CML), cytogenetic abnormalities found in addition to the t(9;22) translocation may impact the response to therapy. Loss of the Y chromosome is generally overlooked in this context, owing to its relatively frequent occurrence in healthy elderly patients. In this multicenter retrospective study, the outcome after imatinib treatment of 30 CML patients with karyotype showing Y chromosome loss (Y-) was compared to 30 Y+ control males diagnosed and treated at the same time in the same institutions. Y- patients had significantly delayed cytogenetic and molecular responses, lower event-free survival and shorter overall survival than Y+ patients. The negative impact of this abnormality was particularly marked when it occurred in a sub-clone (clonal evolution) rather than in all mitoses. These data indicate that loss of the Y chromosome should be taken into account in the prognostic evaluation of chronic myelogenous leukemia patients.

Proteomic analysis of malignant B-cell derived microparticles reveals CD148 as a potentially useful antigenic biomarker for mantle cell lymphoma diagnosis.

The diagnosis of mature B-cell neoplasms (MBCN) remains difficult in a number of cases, especially leukemic phases of non-Hodgkin lymphoma, for which discriminating criteria or biomarker are often lacking. To identify new surface biomarkers, we developed an original proteomic approach based on mass spectrometry analysis of plasma membrane microparticles derived from chronic B-cell lymphoproliferations of single patients: chronic lymphocytic leukemia (CLL), small cell lymphoma (SLL) and mantle cell lymphoma (MCL). A straightforward selection process for proteomic-based candidate biomarker identification was further constructed in order to propose potentially useful and relevant biomarkers. Comparison of the lists of the proteins identified in each pathology combined to highly stringent MS validation criteria for protein identification allowed to propose CD148, a membrane receptor with phosphatase activity, as a discriminating biomarker candidate. Flow cytometry analyses, performed on 158 patients and 30 controls, showed that an anti-CD148 antibody stained significantly higher MCL than CLL and SLL circulating cells (p<0.0001), which validates CD148 overexpression in MCL. Our results indicate that a medium or high CD148 expression level may exclude the diagnosis of CLL and high CD148 expression levels (CD148 MFI equal or superior to 2 times the value obtained with CLL/SLL) allows MCL diagnosis to be suspected with 91% specificity (versus CLL and SLL) and 78% sensitivity. This study is one of the first where proteomic strategies allowed to identify a potentially useful biomarker.

Myeloid cell differentiation arrest by miR-125b-1 in myelodysplastic syndrome and acute myeloid leukemia with the t(2;11)(p21;q23) translocation.

Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes that are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold). In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.

ETV6/GOT1 fusion in a case of t(10;12)(q24;p13)-positive myelodysplastic syndrome.

The ETV6/GOT1 fusion, resulting from t(10;12) (q24;p13), has been recently described in a myelodysplastic syndrome. We reported a second case of t(10;12)-positive myelodysplastic syndrome in whom fluorescent in situ hybridization confirmed the non-random translocation but molecular biology analyses revealed a ETV6/GOT1 chimera varying from the first case described.

Polycythemia vera transforming to acute myeloid leukemia and complex abnormalities including 9p homogeneously staining region with amplification of MLLT3, JMJD2C, JAK2, and SMARCA2.

Polycythemia vera (PV) is a clonal stem cell disorder characterized by an excessive erythrocyte production. At diagnosis, a normal karyotype is found in < or =80% of cases, but an abnormal karyotype frequently develops with evolution. Trisomy 9 and gains on 9p are some of the most frequent cytogenetic abnormalities, together with trisomy 8 and del(20q) in both PV and idiopathic myelofibrosis. We report the case of a 54-year-old man whose disease was classified as an acute myeloid transformation of PV. Cytogenetic and multicolor fluorescence in situ hybridization (FISH) analysis detected several chromosomal abnormalities that included an amplification of 9p. Complementary FISH analysis established amplification of the 9p22 approximately p24.3 region including several known genes: MLLT3 (alias AF9), JMJD2C (alias GASC1), JAK2, and SMARCA2 (alias BRM). JAK2(V617F) mutation status was quantitatively assessed by allele-specific quantitative polymerase chain reaction. Although crossing points analysis showed JAK2(V617F) mutated alleles at 52%, it is still impossible to describe conclusively the mutational status of the amplified JAK2 gene within the sole homogeneously staining region, because total genomic DNA was extracted for the analysis and not only DNA from cells with the homogeneously staining region. Gains on 9p being among the most common anomalies in PV, amplification of a gene or genes on this region may play a crucial role in the pathogenesis or evolution of PV.

Confirmation of a novel recurrent association: BCR-ABL t(9;22) and t(19;21).

Association of a t(9;22)(q34;q11), BCR/ABL-positive, with a dic(19;21)(p13;p13) has been described in acute lymphoblastic leukemia in relapse, raising the question of whether this association is recurrent. Described here are two cases, one of myeloproliferative disease and one of acute lymphoblastic leukemia, both presenting a masked t(9;22) and t(19;21). Chromosomal rearrangements were ascertained by fluorescence in situ hybridization (FISH) using locus-specific probes, multicolor FISH, and bacterial artificial chromosome array. These additional observations suggest a nonrandom association.

13q deletions in B-cell lymphoproliferative disorders: frequent association with translocation.

The 13q14 deletion is the most frequent abnormality in chronic lymphocytic leukemias/small lymphocytic lymphomas, and this early rearrangement is observed from the start of the disease. The systematic use of a panel of interphase fluorescence in situ hybridization (FISH) may not reveal some probes (targeting chromosomes 11q, 13q, 17p, and chromosome 12) structural abnormalities. In this series, we analyzed metaphases by conventional cytogenetics, followed by interphase and metaphase fluorescence in situ hybridization. We were able to observe 17 cases of 13q translocations with deletions in eight of them. Three distinct regions were involved by translocations in association with or without deletions: a region centromeric to RB1 (13q11 approximately 13), a zone telomeric to D13D25 (13q21 approximately 31), and a 13q14 region deliniated by RB1 and D13S25. In this area, the deletion was variable: RB1 alone (one case), D13S319 approximately D13S25 (five cases), and from RB1 to D13S25 (two cases). The very high frequency of 13q14 loss suggests that these deletions are of pathogenetic importance, but, the importance of the translocations remains to be determined.

Cytogenetic studies of a series of 43 consecutive secondary myelodysplastic syndromes/acute myeloid leukemias: conventional cytogenetics, FISH, and multiplex FISH.

We report a series of 43 consecutive therapy-related myelodysplastic syndromes (t-MDS) or acute myeloid leukemias (t-AML) observed for 6 years. This series consisted of 26 women and 17 men, ages ranging from 9 to 85 years. These cases were classified into three groups according to the primary diagnosis. Conventional cytogenetic and fluorescent in situ hybridization (FISH)/ multiplex FISH (M-FISH) methods were used to analyze cytogenetic characteristics of secondary MDS/AML. The features of chromosomal abnormalities were linked to the nature of the therapy and protocols used. A considerable proportion of recurrent balanced translocations characterized t-AML secondary to therapy. FISH techniques showed that conventional cytogenetics often underestimated associated translocations; some deletions were in fact derivative chromosomes associated with deletions. After treatment for lymphomas and chronic myeloproliferative diseases, there were more complex unbalanced abnormalities than the control group. Compared to other series, recurrent translocations appeared to be more numerous (25%), probably reflecting an evolution of therapeutic modalities.