A New Antigen Recognized by Cytolytic T Lymphocytes on a Human Kidney Tumor Results from Reverse Strand Transcription

By stimulating blood lymphocytes from a renal cell carcinoma patient in vitro with the autologous tumor cells, we obtained cytolytic T lymphocyte (CTL) clones that killed several autologous and allogeneic histocompatibility leukocyte antigen (HLA)-B7 renal carcinoma cell lines. We identified the target antigen of these CTLs by screening COS cells transfected with the HLA-B7 cDNA and with a cDNA library prepared with RNA from the tumor cells. The antigenic peptide recognized by the CTLs has the sequence LPRWPPPQL and is encoded by a new gene, which we named RU2. This gene is transcribed in both directions. The antigenic peptide is not encoded by the sense transcript, RU2S, which is expressed ubiquitously. It is encoded by an antisense transcript, RU2AS, which starts from a cryptic promoter located on the reverse strand of the first intron and ends up on the reverse strand of the RU2S promoter, which contains a polyadenylation signal. This mechanism of antigen expression is unprecedented and further illustrates the notion that many peptides recognized by T cells cannot be predicted from the primary structure of the major product of the encoding gene. Antisense transcript RU2AS is expressed in a high proportion of tumors of various histological types. It is absent in most normal tissues, but is expressed in testis and kidney, and, at lower levels, in urinary bladder and liver. Short-term cultures of normal epithelial cells from the renal proximal tubule expressed significant levels of RU2AS message and were recognized by the CTLs. Therefore, this antigen is not tumor specific, but corresponds to a self-antigen with restricted tissue distribution

miR-15a-5p and miR-21-5p contribute to chemoresistance in cytogenetically normal acute myeloid leukaemia by targeting PDCD4, ARL2 and BTG2

Cytarabine and daunorubicin are old drugs commonly used in the treatment of acute myeloid leukaemia (AML). Refractory or relapsed disease because of chemotherapy resistance is a major issue. microRNAs (miRNAs) were incriminated in resistance. This study aimed to identify miRNAs involved in chemoresistance in AML patients and to define their target genes. We focused on cytogenetically normal AML patients with wild-type NPM1 without FLT3-ITD as the treatment of this subset of patients with intermediate-risk cytogenetics is not well established. We analysed baseline AML samples by small RNA sequencing and compared the profile of chemoresistant to chemosensitive AML patients. Among the miRNAs significantly overexpressed in chemoresistant patients, we revealed miR-15a-5p and miR-21-5p as miRNAs with a major role in chemoresistance in AML. We showed that miR-15a-5p and miR-21-5p overexpression decreased apoptosis induced by cytarabine and/or daunorubicin. PDCD4, ARL2 and BTG2 genes were found to be targeted by miR-15a-5p, as well as PDCD4 and BTG2 by miR-21-5p. Inhibition experiments of the three target genes reproduced the functional effect of both miRNAs on chemosensitivity. Our study demonstrates that miR-15a-5p and miR-21-5p are overexpressed in a subgroup of chemoresistant AML patients. Both miRNAs induce chemoresistance by targeting three pro-apoptotic genes PDCD4, ARL2 and BTG2

Translocation breakpoints in FHIT and FRA3B in both homologs of chromosome 3 in an esophageal adenocarcinoma

Common fragile sites have been proposed to play a mechanistic role in chromosome translocations and other rearrangements in cancer cells in vivo based on their behavior in vitro and their co-localization with cancer translocation breakpoints. This hypothesis has been the subject of controversy, because associations have been made at the chromosomal level and because of the large number of both fragile sites and cancer chromosome breakpoints. Tests of this hypothesis at the molecular level are now possible with the cloning of common fragile site loci and the use of fragile site clones in the analysis of rearranged chromosomes. FRA3B, the most frequently seen common fragile site, lies within the large FHIT gene. It is now well established that this region is the site of frequent, large intragenic deletions and aberrant transcripts in a number of tumors and tumor cell lines. In contrast, only one tumor-associated translocation involving the FHIT gene has been reported. We have found translocations in both homologs of chromosome 3 in an early-passage esophageal adenocarcinoma cell line. This cell line showed no normal FHIT transcripts by reverse transcription polymerase chain reaction. Subsequent chromosome analysis showed translocations of the short arms of both homologs of chromosome 3: t(3;16) and t(3;4). The breakpoints of both translocations were shown by fluorescence in situ hybridization and polymerase chain reaction to be in the FHIT gene, at or near the center of the fragile site region. Using rapid amplification of cDNA ends with FHIT primers, a noncoding chimeric transcript resulting from t(3;16) was identified. These data provide direct support for the hypothesis that FRA3B , and likely other common fragile sites, may be “hot spots” for translocations in certain cancers, as they are for deletions, and that such translocations have the potential to form abnormal chimeric transcripts. In addition, the results suggest selection for loss of a functional FHIT gene by the translocation events. © 2001 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35130/1/1095_ftp.pd

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

Refinement of 1p36 Alterations Not Involving PRDM16 in Myeloid and Lymphoid Malignancies

Fluorescence in situ hybridization was performed to characterize 81 cases of myeloid and lymphoid malignancies with cytogenetic 1p36 alterations not affecting the PRDM16 locus. In total, three subgroups were identified: balanced translocations (N = 27) and telomeric rearrangements (N = 15), both mainly observed in myeloid disorders; and unbalanced non-telomeric rearrangements (N = 39), mainly observed in lymphoid proliferations and frequently associated with a highly complex karyotype. The 1p36 rearrangement was isolated in 12 cases, mainly myeloid disorders. The breakpoints on 1p36 were more widely distributed than previously reported, but with identifiable rare breakpoint cluster regions, such as the TP73 locus. We also found novel partner loci on 1p36 for the known multi-partner genes HMGA2 and RUNX1. We precised the common terminal 1p36 deletion, which has been suggested to have an adverse prognosis, in B-cell lymphomas [follicular lymphomas and diffuse large B-cell lymphomas with t(14;18)(q32;q21) as well as follicular lymphomas without t(14;18)]. Intrachromosomal telomeric repetitive sequences were detected in at least half the cases of telomeric rearrangements. It is unclear how the latter rearrangements occurred and whether they represent oncogenic events or result from chromosomal instability during oncogenesis

Apport récent de la cytogénétique dans la caractérisation des hémolymphopathies chroniques B

Cancer is thought tot be the consequence of an accumulation of genetic defects. Cytogenetic and molecular techniques allowed the identification of recurrent and nonrecurrent, specific and nonspecific chromosome and/or gene aberrations. In haematological disorders, several characteristic abnormalities have been observed and listed, allowing for the identification of clinic-pathological entities. The presence of particular aberrations in some disorders has led to the investigation of their role in the pathogenesis and progression of those malignancies. Chronic B-cell lymphoproliferative disorders encompass a variety of diseases. Their distinction is sometimes difficult, and is mainly based on morphologic and immunophenotypic features. Their cytogenetic characterization has been hampered by their low mitotic index. The discovery and systematic use of B-cell mitogens paved the way for more successful cytogenetic investigations. In the present study, the different chronic B-cell lymphoproliferative disorders are reviewed, and new entities are identified and characterized : - chronic B-cell lymphoproliferative disorders with translocation t(14;19) and rearrangement of the BCL3 gene, - chronic B-cell lymphoproliferative disorders with deletion of the long arm of chromosome 12, - chronic B-cell lymphoproliferative disorders with deletion of the long arm of chromosome 7, - chronic lymphoproliferative disorders presenting with cold agglutinin disease and trisomy 3, - non-Hodgkin’s lymphoma with rearrangement of the BCL6 gene, - marginal zone non-Hodgkin’s lymphoma, - non-Hodgkin’s lymphoma with translocations involving the λ light chain gen, - chronic B-cell lymphoproliferative disorders with dual (B and T) rearrangement, - Waldenström’s disease, - plasma cell disorders with t(11;14) or Burkitt-type translocations. The major contribution of cytogenetic to the differential diagnosis is clearly evidenced. Moreover, the prognostic value of the karyotype is demonstrated. Finally, the contribution of chromosomal analysis, complemented by molecular cytogenetic techniques, to a better understanding of underlying pathogenetic mechanisms is shown: - the region q13–q15 is commonly duplicated in case of dup(12q), - the region q31-q32 is commonly duplicated in case of del(7q), - the region q11-q29 is commonly duplicated in case of cold agglutinin syndrome with partial trisomy 3Les cancers sont lies à des anomalies génétiques qui s’accumulent dans les cellules. Les techniques de cytogénétique et de biologie moléculaire ont permis ma mise en évidence d’anomalies chromosomiques et/ou géniques, récurrentes ou non, spécifiques ou non. Dans les hémopathies, de nombreuses aberrations chromosomiques caractéristiques ont pu être ainsi répertoriées. L’analyse de ces répertoires a mené à l’identification d’entités clinico-pathologiques. L’existence d’aberrations chromosomiques non aléatoires dans certaines hémopathies a conduit à étudier leur rôle dans la genèse et la progression des pathologies considérées. Les hémolymphopathies chroniques B constituent un vaste groupe d’affections dont la distinction, parfois malaisée, repose essentiellement sur des critères morphologiques et immunologiques. Leur caractérisation cytogénique a été tardive par rapport à celle des leucémies aigües et des pathologies myéloïdes. En effet, le faible index mitotique de la cellule B maligne rend la croissance des lymphocytes anomaux et donc la détection d’anomalies clonales difficiles, en particulier dans les pathologies du lymphocyte B dit « mature ». A la suite de l’introduction de mitogène B, la cytogénétique des hémolymphopathies chroniques B a connu un essor considérable. Dans ce travail, de nouvelles entités sont individualisées et caractérisées parmi les différents groupes d’hémolymphophaties chronique B : - les hémolymphopathies chroniques B avec translocation t(14 ;19) et réarrangement du gène BCL3, - les hémolymphopathies chroniques B avec duplication du bras long du chromosome 12, - les hémolymphopathies chroniques B avec délétion du bras long du chromosome 7, - les hémolymphopathies chroniques B avec trisomie 3 et se présentant sous forme de maladie des agglutinines froides, - les lymphomes non hodgkiniens avec réarrangement du gène BCL6, ) les lymphomes de la zone marginale, les lymphomes non hodgkiniens avec translocation impliquant le gène de la chaîne légère λ, - les hémolymphopathies chroniques B avec double réarrangement (B et T), ) – les maladies de Waldenström, - les dyscrasies plasmocytaires avec translocation t(11 ;14) et translocations de type Burkitt. ensuite, la valeur da caryotype comme outil complémentaire au diagnostic est démontrée, en particulier dans les hémolymphopathies chroniques B avec essaimage leucémique. La valeur pronostique de l’analyse cytogénétique est documentée. Enfin, certaines anomalies chromosomiques sont précisées à l’aide des techniques récentes de cytogénétique moléculaire, dans l’optique d’une meilleure compréhension des mécanismes pathogéniques sous-jacents : - la région communément dupliquée en vas du dup(12q) est le segment q13-q15, - la région communément délétée en cas de del(7) est le segment q31-q32, - la région communément dupliquée en cas de trisomie partielle du chromosome 3 dans la maladie des agglutinines froides est la région q11-q29Thèse de doctorat en sciences médicales (génétique hématologique) -- UCL, 199

Gammapathies monoclonales de signification indéterminée

peer reviewe

5q-, Twenty-five years later: A synopsis

Twenty-five years have elapsed since the first case of del(5q) was discovered in this laboratory. It was reported in 1974 with other subsequently found cases. As the sole anomaly or together with other chromosome changes, deletions of the long arm of 5 have been found in a large variety of hematologic disorders, but especially in myelodysplastic syndromes (MDS) and in acute myelogenous leukemia (AML). Deletions of 5q are the most frequent chromosome anomaly in therapy-induced myelodysplasia/AML. A clinically distinct entity is the 5q- syndrome in which 5q- is the only change in which female sex prevails. Leukemic transformation is low and survival relatively long. Although the myeloid lineage is predominantly affected in 5q- associated disorders, lymphoid disorders, including 5q- acute lymphoblastic leukemia (B and T) exist and show male predominance. The underlying molecular lesions in 5q- myeloid disorders are still largely unknown. There seems to be a critical segment in 5q31, and preliminary studies suggest the inactivation of one or more genes within that region, deletions of which at the molecular level may be heterogeneous. (C) Elsevier Science Inc., 1997

[Des effets pervers d'une habitude apparemment anodine…]

We report the case of a 47-year old woman with a long history of arterial hypertension. Because of a recent difficulty to control blood pressure values accompanied by hypokalaemia, a thorough investigation was performed, showing low renin and aldosterone blood levels and high urinary potassium levels. Repeated questionings revealed that the patient regulary consumed non-negligible quantities of liquorice-flavoured chewing-gum. The physiopathogenic mechanisms of action of liquorice are reviewed