Aplicació de la citogenètica convencional i la hibridació in situ a l'estudi de síndromes limfoproliferatives cròniques B

Descripció del recurs: 26 febrer 2002Titól obtingut de la portada digitalitzadaLes síndromes limfoproliferatives cròniques B (SLPC-B) són un grup divers de malalties que tenen en comú la proliferació neoplàsica i acumulació de cèl·lules limfoides de tipus B de tipus madur. Dins d'aquest grup, distingim bàsicament les leucèmies i els limfomes. El diagnòstic de les SLPC-B amb expressió leucèmica es basa en l'estudi integrat de la morfologia i l'immunofenotip de les cèl·lules leucèmiques, així com de les característiques citogenètiques i moleculars. Existeixen una sèrie d'entitats que poden ser confoses fàcilment i requereixen un estudi exhaustiu que permeti la seva classificació correcta. En el present treball s'analitzen tres d'aquestes entitats, la Leucèmia Limfàtica Crònica B atípica (LLC-Ba), el Limfoma de Cèl·lules del Mantell (LCM) i el Limfoma Esplènic de la Zona Marginal (LEZM) amb la intenció de trobar marcadors citogenètics que permetin separar-les, de manera que sigui possible establir un diagnòstic diferencial amb certesa. També es fa esment de la limfocitosi B Policlonal Persistent (LBPP). S'han estudiat 27 LLC-Ba, 13 LCM, 19 LEZM i 1 LBPP amb tècniques de citogenètica convencional i hibridació in situ, amb sondes centromèriques pels cromosomes 3, 12, 17 i 18, de locus específic per les regions 13q14 i 17p13 i de pintat cromosòmic. Entre les LLC-Ba, un 37% han presentat alteracions citogenètiques i l'alteració citogenètica més freqüent ha estat la trisomia 12 (63%), mentre que les delecions de 13q14 i 17p13 s'han detectat en % molt baix. Respecte els LCM, el 77% han presentat alteracions citogenètiques i dins d'aquests, en un 70% s'ha detectat la t(11;14)(q13;q32), alteració citogenètica característica d'aquesta entitat. Altres cromosomes implicats han estat: 1, 2, 9, 13 i 17 en forma d'alteracions estructurals principalment. No s'ha detectat la presència de trisomia 12 en cap pacient. En els LEZM, un 58% han presentat un cariotip alterat. Els cromosomes més freqüentment implicats han estat: 1, 3, 7, 8 i 14. Dels estudis inclosos en la tesi i d'altres posteriors s'han pogut definir la trisomia parcial del braç llarg del cromosoma 3 (+3q) i la delecioó del braç llarg del cromosoma 7 (del(7q)) com a alteracions més freqüents. No s'ha detectat presència de t(11;14) en cap dels casos, i la trisomia 12, així com la deleció de 17p13 només s'ha detectat en un pacient. D'aquest estudi es conclueix que les alteracions citogenètiques dels tres grups són clarament diferents i que el seu coneixement permet establir un millor diagnòstic diferencial d'aquestes malalties. La LBPP és una entitat que encara no se sap si és una neoplàsia de progressió lenta, o un fenòmen reactiu. S'ha inclòs en l'estudi amb la intenció de fer esment de la seva existència i de la possibilitat de ser confosa amb alguna de les altres entitats.B-cell lymphoproliferative disorders (BCLPD) constitute a group of pathologies in which mature B cells proliferate and accumulate in different tissues. Among BCLPD, leukaemic and lymphomatous diseases can be distinguished. In the present work, BCLPD with leukaemic expression are studied, taking into account at the same time morphologic, immunophenotypic, cytogenetic and molecular data. It is remarkable that the diagnosis of some BCLPD with leukaemic expression can be difficult because of some similar characteristics. In these cases, an exhaustive study will be required to a correct classification. In this thesis, three different entities would be analyzed: atypical B-cell lymphocytic leukaemia (aCLL), mantle cell lymphoma (MCL) and splenic marginal zone B-cell lymphoma (SMZBCL). The aim of the present study was to study the above mentioned entities by means of conventional cytogenetics and in situ hybridization techniques to analyze if different cytogenetic markers could be identified to establish a differential diagnosis among them. In addition, persistent polyclonal B-cell lymphocytosis (PPBL) was included in the study. Twenty seven aCLL, 13 MCL, 19 SMZBCL and 1 (PPBL) were studied cytogenetically and using in situ hybridization probes for centromeric regions of chromosomes 3, 12, 17 and 18, and for specific locus 13q14 (Rb) and 17p13 (p53). Among aCLL, 37% presented cytogenetic aberrations, being trisomy 12 the most frequent abnormality (63%), besides, 13q14 and 17p13 deletions were found in low percentage. Regarding MCL, chromosomal aberrations were found in 77% of patients, and among them, 70% presented a t(11;14)(q13;q32). Other affected chromosomes were 1, 2, 9, 13 and 17. No patient presented trisomy 12. In SMZBCL group, an abnormal karyotype was found in 58% of patients. The most frequently involved chromosomes were 1, 3, 7, 8 and 14. The most frequent structural abnormalities associated to SMZBCL were +3q and del(7q). No case presented +12, nor t(11;14)(q13;q32), and only one case showed 17p13 deletion. In conclusion, cytogenetic abnormalities seem to be different in each studied group, and its knowledge could be useful to establish a differential diagnosis among these pathologies. PPBL still is a controversial entity, because it is not clear if it represents a neoplastic disease with a very slow progression rate or if it represents a reactive phenomena

Absence of MALT1 traslocation in primary cutaneous marginal zone B-cell lymphoma

The implication of MALT1 gene in the pathogenesis of primary cutaneous marginal zone B-cell lymphomas (PCMZL) has been a matter of controversy. We examined the presence of MALT1 translocations in a series of 23 PCMZL. FISH assay with a MALT1 dual color break apart translocation probe revealed the absence of MALT1 translocations in all cases

Palaeohistology reveals a slow pace of life for the dwarfed Sicilian elephant

Altres ajuts: CERCA Programme/Generalitat de CatalunyaThe 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be 'r-selected' by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals

Comparative Analysis of TCR-gamma Gene Rearrangements by Genescan and Polyacrylamide Gel-electrophoresis in Cutaneous T-cell Lymphoma

Demonstrating T-cell clonality has become an important approach supporting a diagnosis of malignant T-cell neoplasms. A comparative study between Genescan analysis, polyacrylamide gel and agarose gel electrophoresis in visualizing X-cell receptor gamma gene rearrangement was performed on 25 biopsy specimens from 18 patients with different forms of cutaneous T-cell lymphomas. Clonality was detected in 17 biopsy specimens when PCR products were evaluated by Genescan analysis. Seventeen showed discrete bands when visualized in polyacrylamide gel and 14 cases were clonal when visualized with agarose gel. In five cases, a clonal population was seen in the gels, but not with Genescan. On sequencing the PCR products we demonstrated nonclonality of these five samples. Our results confirm that PCR-Genescan is a useful, reliable and specific screening method for detecting dominant clones in patients with T-cell lymphoma

Integrated analysis of whole-exome sequencing and transcriptome profiling in males with autism spectrum disorders

BACKGROUND: Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders with high heritability. Recent findings support a highly heterogeneous and complex genetic etiology including rare de novo and inherited mutations or chromosomal rearrangements as well as double or multiple hits. METHODS: We performed whole-exome sequencing (WES) and blood cell transcriptome by RNAseq in a subset of male patients with idiopathic ASD (n = 36) in order to identify causative genes, transcriptomic alterations, and susceptibility variants. RESULTS: We detected likely monogenic causes in seven cases: five de novo (SCN2A, MED13L, KCNV1, CUL3, and PTEN) and two inherited X-linked variants (MAOA and CDKL5). Transcriptomic analyses allowed the identification of intronic causative mutations missed by the usual filtering of WES and revealed functional consequences of some rare mutations. These included aberrant transcripts (PTEN, POLR3C), deregulated expression in 1.7% of mutated genes (that is, SEMA6B, MECP2, ANK3, CREBBP), allele-specific expression (FUS, MTOR, TAF1C), and non-sense-mediated decay (RIT1, ALG9). The analysis of rare inherited variants showed enrichment in relevant pathways such as the PI3K-Akt signaling and the axon guidance. CONCLUSIONS: Integrative analysis of WES and blood RNAseq data has proven to be an efficient strategy to identify likely monogenic forms of ASD (19% in our cohort), as well as additional rare inherited mutations that can contribute to ASD risk in a multifactorial manner. Blood transcriptomic data, besides validating 88% of expressed variants, allowed the identification of missed intronic mutations and revealed functional correlations of genetic variants, including changes in splicing, expression levels, and allelic expression. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13229-015-0017-0) contains supplementary material, which is available to authorized users

MicroRNA expression profiling and DNA methylation signature for deregulated microRNA in cutaneous T-cell lymphoma

MicroRNAs usually regulate gene expression negatively, and aberrant expression has been involved in the development of several types of cancers. Microarray profiling of microRNA expression was performed to define a microRNA signature in a series of mycosis fungoides tumor stage (MFt, n=21) and CD30+ primary cutaneous anaplastic large cell lymphoma (CD30+ cALCL, n=11) samples in comparison with inflammatory dermatoses (ID, n=5). Supervised clustering confirmed a distinctive microRNA profile for cutaneous T-cell lymphoma (CTCL) with respect to ID. A 40 microRNA signature was found in MFt including upregulated onco-microRNAs (miR-146a, miR-142-3p/5p, miR-21, miR-181a/b, and miR-155) and downregulated tumor-suppressor microRNAs (miR-200ab/429 cluster, miR-10b, miR-193b, miR-141/200c, and miR-23b/27b). Regarding CD30+ cALCL, 39 differentially expressed microRNAs were identified. Particularly, overexpression of miR-155, miR-21, or miR-142-3p/5p and downregulation of the miR-141/200c clusters were observed. DNA methylation in microRNA gene promoters, as expression regulatory mechanism for deregulated microRNAs, was analyzed using Infinium 450K array and approximately one-third of the differentially expressed microRNAs showed significant DNA methylation differences. Two different microRNA methylation signatures for MFt and CD30+ cALCL were found. Correlation analysis showed an inverse relationship for microRNA promoter methylation and microRNA expression. These results reveal a subgroup-specific epigenetically regulated microRNA signatures for MFt and CD30+ cALCL patients

In situ mantle cell lymphoma: clinical implications of an incidental finding with indolent clinical behavior

Background Cyclin D1-positive B cells are occasionally found in the mantle zones of reactive lymphoid follicles, a condition that has been called 'in situ mantle cell lymphoma'. The clinical significance of this lesion remains uncertain. Design and Methods The clinical and pathological characteristics, including SOX11 expression, of 23 cases initially diagnosed as in situ mantle cell lymphoma were studied. Results Seventeen of the 23 cases fulfilled the criteria for in situ mantle cell lymphoma. In most cases, the lesions were incidental findings in reactive lymph nodes. The t(11; 14) was detected in all eight cases examined. SOX11 was positive in seven of 16 cases (44%). Five cases were associated with other small B-cell lymphomas. In two cases, both SOX11-positive, the in situ mantle cell lymphoma lesions were discovered after the diagnosis of overt lymphoma; one 4 years earlier, and one 3 years later. Twelve of the remaining 15 patients had a follow-up of at least 1 year (median 2 years; range, 1-19.5), of whom 11 showed no evidence of progression, including seven who were not treated. Only one of 12 patients with an in situ mantle cell lymphoma lesion and no diagnosis of mantle cell lymphoma at the time developed an overt lymphoma, 4 years later; this case was also SOX11-positive. The six remaining cases were diagnosed as mantle cell lymphoma with a mantle zone pattern. Five were SOX11-positive and four of them were associated with lymphoma without a mantle zone pattern. Conclusions In situ mantle cell lymphoma lesions are usually an incidental finding with a very indolent behavior. These cases must be distinguished from mantle cell lymphoma with a mantle zone pattern and overt mantle cell lymphoma because they may not require therapeutic intervention

Trisomy 8, A Cytogenetic Abnormality In Myelodysplastic Syndromes, Is Constitutional Or Not?

Isolated trisomy 8 is not considered presumptive evidence of myelodysplastic syndrome (MDS) in cases without minimal morphological criteria. One reason given is that trisomy 8 (+8) can be found as a constitutional mosaicism (cT8M). We tried to clarify the incidence of cT8M in myeloid neoplasms, specifically in MDS, and the diagnostic value of isolated +8 in MDS. Twenty-two MDS and 10 other myeloid neoplasms carrying +8 were studied. Trisomy 8 was determined in peripheral blood by conventional cytogenetics (CC) and on granulocytes, CD3+ lymphocytes and oral mucosa cells by fluorescence in situ hybridization (FISH). In peripheral blood CC, +8 was seen in 4/32 patients. By FISH, only one patient with chronic myelomonocytic leukemia showed +8 in all cell samples and was interpreted as a cT8M. In our series +8 was acquired in all MDS. Probably, once discarded cT8M by FISH from CD3+ lymphocytes and non-hematological cells, +8 should be considered with enough evidence to MDS

Oligonucleotide array-CGH identifies genomic subgroups and prognostic markers for tumor stage mycosis fungoides

Mycosis fungoide (MF) patients who develop tumors or extracutaneous involvement usually have a poor prognosis with no curative therapy available so far. In the present European Organization for Research and Treatment of Cancer (EORTC) multicenter study, the genomic profile of 41 skin biopsies from tumor stage MF (MFt) was analyzed using a high-resolution oligo-array comparative genomic hybridization platform. Seventy-six percent of cases showed genomic aberrations. The most common imbalances were gains of 7q33.3q35 followed by 17q21.1, 8q24.21, 9q34qter, and 10p14 and losses of 9p21.3 followed by 9q31.2, 17p13.1, 13q14.11, 6q21.3, 10p11.22, 16q23.2, and 16q24.3. Three specific chromosomal regions, 9p21.3, 8q24.21, and 10q26qter, were defined as prognostic markers showing a significant correlation with overall survival (OS) (P=0.042, 0.017, and 0.022, respectively). Moreover, we have established two MFt genomic subgroups distinguishing a stable group (0-5 DNA aberrations) and an unstable group (>5 DNA aberrations), showing that the genomic unstable group had a shorter OS (P=0.05). We therefore conclude that specific chromosomal abnormalities, such as gains of 8q24.21 (MYC) and losses of 9p21.3 (CDKN2A, CDKN2B, and MTAP) and 10q26qter (MGMT and EBF3) may have an important role in prognosis. In addition, we describe the MFt genomic instability profile, which, to our knowledge, has not been reported earlier