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G Echezarreta

Publications and source records attributed to G Echezarreta.

At least 19 recordsLinked to original sources
PubMed1998

Increased C-MYC oncogene copy number detected with combined modified comparative genomic hybridization and FISH analysis in a Richter syndrome case with complex karyotype.

Modified comparative genomic hybridization (mCGH) was performed in a Richter syndrome case with a complex karyotype to identify and map gains of DNA sequences with possible importance in the pathogenesis and progression of the tumor. The mCGH analysis revealed a more intense signal on part of the long arm of one pair of chromosomes belonging to group C. The G-banding study showed that the increased DNA-sequence copy number originated from the 8q22-->qter chromosomal region. This increase was confirmed by performing a fluorescence in situ hybridization analysis on tumor metaphases by first using a chromosome 8-specific library and subsequently a C-MYC probe, which revealed positive staining on six different regions located on six different chromosomes, each one bearing a single copy of the C-MYC oncogene. These results show the existence of C-MYC oncogene copy-number increases and confirm the usefulness of mCGH in the genetic analysis of malignancies.

Aged↗
PubMed1998

Hypermethylation of p15/ink4b/MTS2 gene is differentially implicated among non-Hodgkin's lymphomas.

P15 (MTS2) gene is a candidate tumor suppressor gene localized adjacent to the p16 gene at 9p21. Deletions at the 9p21 region frequently affect both p16 and p15 genes, however, mutations in the coding sequence of the p15 gene have not been found in the majority of tumors analyzed, including non-Hodgkin's lymphomas. Abnormal methylation of the promoter region of p15 has been recently described as an alternative mechanism of inactivation of this gene. We analyzed 72 non-Hodgkin's lymphomas (NHL) for methylation at p15 exon 1 by PCR and Southern blot techniques using methylation-sensitive restriction enzymes. Abnormal methylation was found in eight cases (11%), most of them (three MALT, one anaplastic T cell lymphoma, one Burkitt and one follicular lymphoma) showing hypermethylation in the p16 gene also. In contrast, two pleomorphic T cell NHL showed a selective methylation at p15 gene, while the p16 gene remained unmethylated. The results show that methylation at the p15 gene is frequently associated with p16 methylation in NHL, and suggest that selective methylation of p15, although uncommon, could be a specific alteration implicated in T cell NHL.

Carrier Proteins↗
PubMed1998

[Correlation of flow and static cytometry; their application to the study of anaplastic lymphomas].

PURPOSE: DNA study by cytometric methods is one of the prognosis factors considered in malignant tumours. Flow cytometry (FCM) was the most frequently used techniques in cell suspensions. Image cytometry (ICM) was also applied in cellular smears and it is possible to measure the results with an Image Analyzer, which supposes a substancial advantage over DNA studies. To confirm the results and correlation of the two techniques a controversial subtype of lymphoid tumour was selected: Anaplastic large cell lymphoma (ALCL). MATERIAL AND METHODS: Fifty four cases of ALCL (23 classical type and 31 ACL-Hodgkin related) were studied. Cytometry was performed in paraffin-embedded tissues previously dewaxed, rehydrated and minced. FCM was done in suspensions incubated with ribonuclease A and stained with propidium iodide in an EPICS-C flow cytometer. ICM study was performed in Feulgen-stained smears and measured by an Image Analyzer CAS-200. RESULTS: All cases were aneuploid. ALCL were 30.5% hypodiploid (HpD) and 69.5% hyperdiploid (HrD) by FCM; 43.5% HpD and 56.5% HrD by ICM. ALCL-HR were 58% HpD and 42% HrD by FCM; 68% HpD and 32% HrD by ICM. There was a lack of correlation of 22% between both methods but it was not statistically significant. CONCLUSIONS: We can conclude the obtained results by FCM and ICM are almost similar.

Aneuploidy↗
PubMed1997

Correlation between mutations in p53 gene and protein expression in human lymphomas.

A discordance between p53 protein overexpression and the presence of mutations in the gene has been observed in many types of tumors, including human lymphomas. To probe this finding, we have studied a large series of 94 lymphomas of different pathologic types and histologic differentiation. Analyzing exons 5-9, we have found mutations in the p53 gene in 7 of 94 cases distributed in different subtypes: 4/12 (33%) high-grade B-cell non-Hodgkin's lymphomas (B-NHLs), in 1 of 5 (20%) high-grade mucosa-associated lymphomas (MALT), in 1 of 22 (4.5%) anaplastic large cell lymphoma (ALCL), and in 1 of 24 (4%) T-cell NHLs. Immunostaining with anti-p53 antibody DO-7 was possible in 87 lymphomas, and overexpression of p53 protein was observed in 16 cases (18%). A discrepancy between the results of SSCP and immunostaining was detected on 18 tumor samples. Two cases with mutations in the gene showed no altered protein expression and 16 cases overexpressed p53 protein had no point mutations. In these cases, the possibility that mutations occur outside the exons studied has been tested and the entire coding sequence analyzed. Only one case showed a mutation in exon 10, and we found two cases carrying a polymorphism in exon 4 and in intron 10. We conclude that mutations in p53 occur mainly in high-grade B-cell NHLs. Although not limited to a specific subtype of lymphoma, they may be rare in Hodgkin's disease and in low-grade lymphomas. The discrepancies between overexpression and presence of mutations suggest (1) the existence of another mechanism to stabilize the p53 protein, and (2) that the immunohistochemistry cannot be used to predict mutations in the gene.

Antibodies, Monoclonal↗
PubMed1997

Role of nitric oxide in autocrine control of growth and apoptosis of endothelial cells.

Nitric oxide (NO) is a growth inhibitor for diverse cellular types. In the present study, we have found that the inhibition of NO production in bovine endothelial cells by an L-arginine competitive antagonist induces DNA replication and promotes the transition from prereplicative to replicative phases of the endothelial cell cycle and an increase in c-myc and c-fos oncogene-encoded protein expression. The inhibition of NO generation had, however, a markedly different outcome depending on the state of confluence of the cells, i.e., proliferation was found in subconfluent cells, whereas apoptosis occurred in confluent cells. Moreover, Western blot analysis revealed differences in the constitutive NO synthase expression in proliferating compared with growth-arrested cells. In conclusion, these results disclose an alternative mechanism of endothelial cell apoptosis at the confluent state, which is related to NO inhibition. Moreover, the fact that the apoptotic phenomenon occurred in the presence of growth factors indicates the existence of apoptotic mechanisms that do not require growth factor deprivation.

Animals↗
PubMed1997

[Value of protein 53 expression in lymphoma. Its correlation with genetic mutations].

PURPOSE: p53 is a tumour suppressor gene encoding a nuclear phosphoprotein that plays an important role in the control of normal cell proliferation. We have tried to establish the value of expression of the p53 protein in malignant lymphomas and its correlation with the presence of structural gene abnormalities. MATERIAL AND METHODS: 230 cases of lymphomas (11 Hodgkin's disease and 219 non-Hodgkin's) were studied by immunohistochemistry using an anti-p53 monoclonal antibody (DO-7, DAKO). Sections were heated by pressure cooker in 0.01 M sodium citrate buffer pH 6 as a method for antigen unmasking. The quantification of levels of nuclear p53 protein were measured with an Image Analyzer (CAS-200, Becton-Dickinson S.A.). We have also searched for mutations in a series of 94 lymphomas using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis in exons 5 to 9 of the p53 gene and the sample showing abnormal pattern were sequenced. RESULTS: p53 immunoreactivity has been detected in 82.6% of cases. The percentage of positive cells varies in a wide range which was divided into 0% (17.39%), less than 5% (57.39%), between 5-10% (13.91%) and more than 10% (11.30%). In all lymphoma subtypes, we have found the majority of cases show levels less than 10% and few more than 10%. We found abnormal bands in 9 of 94 lymphomas with different diagnosis (1 ALCL, 1 T-LNH, 2 B-LNH, 2 centroblastic, 1 lymphoblastic and 2 MALT). Two cases resulted to be a silent base change which not alter the function of the p53 protein and represent a common polymorphism. Seven cases showed single base pair missense mutations in all of them. Mutations in codons 179, 248 and 273 correspond to some of the typical hotspots described in p53 gene. CONCLUSIONS: p53 expression, is a frequent finding in malignant lymphomas, is variable and relates to histological subtype. The results suggest that positive immunocytochemistry cannot be used to determine which tumours have mutations of p53 because the existence of cases with discrepancies between overexpression of the protein and presence of mutations.

DNA Mutational Analysis↗
PubMed1996

[Clinico-morphologic reconsideration of anaplastic lymphoma. Retrospective study of 60 patients with aggressive clinical course and multiple recurrences].

PURPOSE: To identify anaplastic large cell lymphoma Ki-1+ (ALCL-Ki-1+) among a group of patients with aggressive Hodgkin's disease (HD) and to know the biological behaviour of the neoplasia (ALCL-Ki-1+). PATIENTS AND METHODS: Biopsies and clinical data of sixty patients with previous morphological diagnosis of HD lymphocytic depletion (LD), syncytial variant of nodular esclerosis (NE-II) and other subtypes of HD with aggressive clinical features were reviewed. A morphological, immunohistochemical (IHQ), proliferative and flow cytometric (FCM) studies were performed in lymph node biopsies. RESULTS: Morphological study and IHQ identify three groups: 15 patients (25%) lymphocytic predominance (LP) HD, 36 (60%) ALCL-Ki-1+ and 9 (15%) of non-Hodgkin's lymphoma (NHL) and unclassifiable cases. Nine cases of LP show anaplastic and variable immunophenotype being the rest of B-cell nature. 75% of LP patients showed long survival and frequent second neoplasias (47%). ALCL-Ki-1+ group had good initial response to therapy (84%) and multiple relapses, 67% showed CD15 positive marker (the so-called ALCL-HD related). CONCLUSIONS: A retrospective study of a selected group of patients previously diagnosed of aggressive HD showed different pathological subtypes: LP, LP with anaplastic areas, ALCL-Ki-1+ Hr (Hodgkin's related) and ALCL-Ki-1+ (classical type), all of them were CD30+, which could represent different stages of the same neoplasia.

Adolescent↗
PubMed1995

Immunohistochemistry in apparently normal bone marrow trephine specimens from patients with nodal follicular lymphoma.

AIM: To establish the role of immunohistochemistry (using a limited panel of antibodies) in detecting minimal involvement by follicular lymphoma in routinely processed bone marrow trephine specimens, which show no obvious morphological (light microscopic) evidence of lymphoma; to determine whether bcl-2 immunostaining in bone marrow distinguishes between benign and malignant infiltrates in a patient with nodal follicular lymphoma. METHODS: Twenty seven consecutively selected paraffin wax embedded, formalin fixed bone marrow trephine specimens were stained with the following antibodies: anti-bcl-2, anti-CD79a, anti-CD3, and kappa and lambda light chains, using the Streptavidin biotin complex technique. RESULTS: Five of the 27 cases, which showed no evidence of involvement by follicular lymphoma on routine stains, showed monotypic B cells on immunohistochemistry. Two of the cases were diffuse, while the remaining three showed mini-aggregates around bony trabeculae. In all five cases the lymphomatous infiltrates were strongly bcl-2 positive. Reactive B lymphoid nodules did not show the same degree of bcl-2 positivity, and negative cells could be discerned within the reactive nodules. CONCLUSIONS: There is merit in studying so-called negative bone marrows immunohistochemically in order to detect minimal involvement by follicular lymphoma. A limited panel of antibodies including anti-bcl-2, anti-CD79a and anti-CD3 is usually adequate to accomplish this. Strongly bcl-2 positive lymphoid aggregates in the bone marrow of patients with nodal follicular lymphoma are indicative of lymphoma.

Biopsy↗
PubMed1995

[Large-cell anaplastic lymphomas: a genetic and immunophenotypic study].

PURPOSE: To characterize from a genetic point of view a group of non-Hodgkin's anaplastic large-cell lymphomas (ALCL) by Southern blot and PCR methods with different probes (molecular study) and with direct or post 24-78 hours cultures with GTC banding techniques (cytogenetic). To correlate the results to the immunophenotype performed with a complete panel of monoclonal antibodies (MoAb) according to avidin-biotine and alkaline phosphatase (APAAP) methods. MATERIAL AND METHODS: Sixty cases of ALCL were reviewed and only 19 selected (with frozen or fresh material) because a complete immunohistologic and genotypic correlation had been done. According to CD15 expression two groups were considered, CD15+ (the so-called Hodgkin's related or Hodgkin's like) and CD15- or classical type. RESULTS: Only 26.5% of cases showed immuno -genotypic correlation. Immunohistochemistry is an accurate method for activation, proliferation and B-cell nature, but T-cell cases were not stained because T-cell paraffin markers are not completely specific. CD15 group had only 30% rearranged cases with scarce cytogenetic abnormalities, as it occurs in Hodgkin's disease (HD). ALCL classical type showed 66% rearranged cases, and one of the T-cell cases showed an incomplete t (2:5) translocation or polyploid cell lines. CONCLUSIONS: Both groups have different genetic and immunophenotypic behaviour which resembles HD or NHL. CD15 positive cases or ALCL HD-related constitute a borderline entity which has to be recognized because of the different therapy and clinical behaviour.

Hodgkin Disease↗
PubMed1994

DNA content in non-Hodgkin's lymphoma. Comparison between flow cytometry and cytogenetics in fresh and paraffin-embedded tissue.

DNA content of 36-non-Hodgkin's lymphomas was analyzed by flow cytometry (FCM) and cytogenetics (CG), 21 in fresh and 15 in paraffin-embedded tissue. The results of both techniques were coincident in 60% of the fresh tissue samples and in 45% of the paraffin-embedded ones, the reason for this difference could be the poor resolution of DNA histograms from paraffin-embedded tissue. All samples judged as aneuploid by FCM were aneuploid also by CG. Some samples with a hyperdiploid population by CG gave a diploid population by FCM with a 'false' high DNA-synthesis (S) fraction. From a technical point of view, CG and FCM have to be performed on the same fresh tissue.

Cell Cycle↗
PubMed1994

B-cell follicular lymphomas: clinical and biological characteristics.

Seventy cases of follicular B-cell lymphomas were studied: 37 cases derived from the follicular centre [27 centroblastic-centrocytic (CB-CC) and 10 centroblastic (CB)] and 33 from the mantle zone [mantle-cell lymphoma (ML)]. Presenting features as well as response to therapy, time free of symptoms and survival were reviewed. All the cases were diagnosed and classified with routine and immunohistochemistry methods. In 61 cases tumors were studied with specific markers in a CAS-200 Image Analyser. Flow cytometry (FCM) was also done and correlated with proliferative-values and survival. A minor aggressive course of CB-CC and ML was demonstrated, with ML being the most benign form (lower proliferation rate and longest survival). Ploidy did not correlate with histological subtypes, survival or response to therapy. These results confirm the utility of biodynamic studies in lymphoid neoplasias.

Adult↗
PubMed1993

[Follicular mantle lymphoma: clinicopathologic and cell proliferation of 11 cases].

BACKGROUND: The aim of the present was to study the biologic behavior of the lymphomas of the follicular mantle by analysis of different indexes of neoplastic cell proliferation and their relation with the clinical symptoms, prognosis and survival of the patients. METHODS: Light microscope, ultrastructural, and frozen and paraffin immunohistochemical studies were performed including the proliferative markers Ki-67 and PC10, flow cytometry and analysis of cell cycle in biopsy samples. Clinical data of 11 patients were collected in addition to therapeutic response and survival. RESULTS: Lymphoma of the follicular mantle is constituted by small sized cell elements with a variable pattern of tumoral growth in the lymph nodes. In normal lymphocytes of the follicular mantle the immunophenotype shows expression of IgM + IgD and a light chain in the cell surface. From a clinical point of view, massive splenomegaly and disseminated stage are the most outstanding characteristics. One third of the cases analyzed presented an aneuploid neoplastic population. According to the PC10 marker, the proliferative index ranged from 2.9 to 14.7% of neoplastic cellularity (mean 7.0). The percentage of cells in the phases S, G2 and M of the cell cycle by flow cytometry varied from 14 to 35 (mean 23%). Neither the cell ploidy nor the tumoral proliferative index were related with the survival of the patients (53 +/- 51 months). CONCLUSIONS: Lymphoma of the follicular mantle is a clinical pathological entity of low biologic aggressivity. Cell aneuploidy or ploidy and the tumoral proliferative index did not establish differences in prognosis or survival in this series.

Adult↗
PubMed1993

[Biology of secondary nodal follicular b-lymphomas. A patho-dynamic study].

PURPOSE: To assess the aggressivity factors and tumour prognosis in a series of non-Hodgkin lymphomas by the use of computer-quantified specific antibodies and flow cytometry. PATIENTS AND METHODS: Sixty-one cases of follicular B-cell lymphoma: 34 of the germinal centre (24 centroblastic-centrocytic, CB-CC, and 10 centroblastic, CC) and 27 of the follicular cortex (FCL), were studied. All the cases had been diagnosed between 1971 and 1992 at the Pathology Department of the Fundación Jiménez Díaz. Morphologic and immunophenotype diagnosis was made on each case. Tumour proliferation studies were performed after labelling nuclei with proliferent nucleic acid-associated protein (PC 10); the positive nuclear areas were later quantified in a CAS-200 image analyser by means of proliferation programmes (PI) and nuclear receptors (ER). A flow cytometry study of ploidy was carried out on each case. The values attained were correlated with survival in months. The Wilcoxon's test for independent variables was used for the statistical study. RESULTS: The PI programme showed lowest proliferation for FCL (7.4%) followed by intermediate proliferation in CB-CC (16.9%) and high proliferation in CB (31.7%). The PC-10 results attained with both PI and ER programmes showed statistically significant correlation (p < 0.01). The correlation between ploidy, as quantified by flow cytometry, and survival showed statistically significant differences between diploid and aneuploid cases (p < 0.01); similar findings apply for diploids and diploids with high synthesis phase (p < 0.01). CONCLUSION: These findings support the usefulness of cell kinetics studies in lymphoma, and contribute to validate different evolutive patterns in accordance with the histologic subtype.

Biomarkers, Tumor↗
PubMed1992

Correlation between cytogenetic and molecular analysis of t(14;18) in follicular lymphomas.

A comparison between cytogenetic and molecular results of t(14;18) has been performed in 12 patients with follicular lymphomas: five nodular and seven diffuse. Ten cases showed cytogenetic alterations with different markers, including a 14q+ in eight: in four it was the result of a t(14;18). Molecular analysis by Southern blotting with bcl2 probes from major and minor cluster regions, and PCR with primers from major and minor regions showed differences versus the cytogenetic results. The correlation found between cytogenetic and molecular results suggests other factors, such as geographical differences or different pathogenetic mechanisms, more than methodologic aspects, to explain the different frequencies of this marker among countries.

Adult↗
PubMed1992

A multiparametric study of malignant lymphoma of mucosa associated lymphoid tissue (MALT).

A morphological, immunophenotypic and ultrastructural study, cell cycle estimation, DNA and cytogenetic analysis were performed in ten cases of B-MALT lymphomas. Five had low grade lymphoma and five had high grade. Low and high grade cases showed the same cells but in different percentages: These included centrocyte-like cells with occasional monocytoid cytoplasmic changes, and centroblast-like cells. However, in high grade cases more dysplastic and large cells were present. All cellular types showed an important development of rough endoplasmic reticulum. In all cases a large panel of monoclonal antibodies was employed to study the B-cell immunophenotype. Ki-67 positivity ranged from 5% to 30% in low-grade cases and from 50% to 70% in high-grade cases. Gene rearrangement analysis showed rearrangement with Jh probe and half of the cases were also rearranged with the Kde probe (Kappa constant chain gene). A rearrangement banding pattern with TCR genes was not present in any of the cases. Cytogenetic study showed complex alterations in high grade cases and a normal karyotype in low grade lymphomas. Only one case had rearrangement for the bcl-2 probe.

Female↗
PubMed1992

[The immunological characterization of 63 cases of Hodgkin's disease with a panel of 8 antibodies].

Sixty three cases of Hodgkin's disease are studied (two with lymphonodular predominance, 15 with diffuse lymphocyte predominance, 26 nodular sclerosis, 15 mixed cell and 5 lymphocyte depletion) with a panel of 8 monoclonal antibodies, material routinely used and included in paraffin: Ber H2 (CD30), Leu M1 (CD15), Common Leukocyte Antigen (CD45), L26 (CD20), MB2, UCHL1 (CD45 RO), MTI (CD43) and Epithelial Membrane Antigen. Ber H2 turned out to be the most usefull marker, positive in 100% of cases, independently of the histologic type. Positiveness with Leu M1 ranged from 100% (2/2 cases) of lymphonodular predominance, to 53.3% (8/15 cases) of diffuse lymphocyte predominance. The reactivity of the rest was variable, 1 though it is note worthy the positiveness of B markers (L26, MB2) in the two cases with lymphonodular predominance. In the other subtypes, reactivity with L26 was greater than that with MB2. T cell marker expression was minimal, except for the positiveness in 40% of cases (2/5) of the lymphocyte depletion type. In addition, the results of other series are revised and as a result the possible histogenesis of Hodgkin's disease is discussed.

Antibodies, Monoclonal↗
PubMed1992

[Castleman's disease. A multifactorial study].

A case of Castleman's disease (hialino-vascular subtype) in a female patient 15-years-old is considered. Clinically there were isolated lymphadenopathies which relapsed after surgery and absence of general syndrome. Histoimmunological and electron microscopic studies were performed as DNA rearrangement and cytogenetics in order to exclude genetic abnormalities and monoclonality of this disorder. The role of follicular dendritic component in discussed.

Adolescent↗