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E Campo

Publications and source records attributed to E Campo.

At least 37 records · Page 2Linked to original sources
PubMed2002

Survival after progression in patients with follicular lymphoma: analysis of prognostic factors.

BACKGROUND: The purpose of this study was to identify prognostic parameters for patients with follicular lymphoma (FL) in first progression/relapse. These would be useful for selection of high-risk patients for inclusion in trials aimed at determining the effect of new treatment approaches in such patients. PATIENTS AND METHODS: Ninety patients (48 male, 42 female, median age 56 years) diagnosed with FL, in a single institution during a 20 year period and relapsing/progressing after an initial response to therapy, were recruited. The main end-point of the study was survival from progression (SFP). Univariate and multivariate analyses were performed, including among the predictive variables the response duration (RD) after the initial treatment and the main features of the patients at the first progression or relapse. RESULTS: Five-year SFP was 47% (95% confidence interval 35% to 58%). Patients with RD following initial therapy >2 years had a longer SFP (5-year SFP 63 versus 33%, P = 0.012). Other variables with prognostic interest for SFP were stage at diagnosis and the following variables at relapse: age, bulky disease, performance status, serum lactate dehydrogenase level, serum beta2-microglobulin level, bone marrow involvement, stage and International Prognostic Index rating. In the multivariate analysis, poor performance status at progression and a RD <2 years were the most important unfavorable variables to predict SFP. CONCLUSION: In patients with FL, RD along with performance status at progression are features that predict SFP. These variables could thus be useful to select candidates for experimental treatments.

Age Factors↗
PubMed2001

The FOXP1 winged helix transcription factor is a novel candidate tumor suppressor gene on chromosome 3p.

The JC12 monoclonal antibody recognizes a previously unknown nuclear protein that showed a restricted distribution in normal tonsil and was also overexpressed in a subset of diffuse large B-cell lymphomas. Using this reagent, we expression cloned cDNAs encoding its antigenic target and identified this protein as a novel putative transcription factor, FOXP1. The FOXP1 protein sequence contains predicted domains characteristic of transcription factors, including a winged helix DNA-binding motif, a second potential DNA-binding motif, a C(2)H(2) zinc finger, nuclear localization signals, coiled-coil regions, PEST sequences, and potential transactivation domains. The FOXP1 gene has been mapped to chromosome 3p14.1, a region that commonly shows loss of heterozygosity in a wide range of tumors and which is reported to contain a tumor suppressor gene(s). Using tissue arrays and immunohistochemistry, we demonstrate that both the FOXP1 mRNA and protein are widely expressed in normal tissues. The levels of FOXP1 mRNA were compared in paired normal and tumor tissues (from the same patient) using a tissue array containing cDNAs extracted from 68 samples taken from kidney, breast, prostate, uterus, ovary, cervix, colon, lung, stomach, rectum, small intestine, and from nine cancer cell lines. Differences in FOXP1 mRNA expression between normal and tumor samples were observed in 51% of cases. Most striking was the comparative loss of expression in 73% of colon tumors and comparative overexpression of FOXP1 mRNA in 75% of stomach tumors. Analysis of the FOXP1 mRNA expression in normal tissues (not taken from cancer patients) indicated that loss of FOXP1 expression may occur in some histologically normal tissues adjacent to tumors. Immunohistochemical analysis of FOXP1 protein expression was performed on 128 solid tumors, including 16 renal, 9 breast, 12 lung, 20 colon, 21 stomach, 10 head and neck, 35 prostate, and 5 pancreatic cases. Complete loss of expression, increased expression, and cytoplasmic mislocalization of the predominantly nuclear FOXP1 protein were frequently observed in neoplastic cells. Our study identifies FOXP1 as a new candidate tumor suppressor gene localized to the chromosome 3p14.1 region.

Amino Acid Sequence↗
PubMed2001

Complement-mediated cell death induced by rituximab in B-cell lymphoproliferative disorders is mediated in vitro by a caspase-independent mechanism involving the generation of reactive oxygen species.

Mechanisms involving the in vitro effect of rituximab in cells from 55 patients with B-cell lymphoproliferative disorders were investigated. No cytotoxic effect was observed when cells were incubated with rituximab alone, but in the presence of human AB serum rituximab induced complement-dependent cell death (R-CDC). A cytotoxic effect was observed in cells from 9 of 33 patients with B-cell chronic lymphocytic leukemia, 16 of 16 patients with mantle-cell lymphoma, 4 of 4 patients with follicular lymphoma, and 2 of 2 patients with hairy-cell leukemia. R-CDC was observed in cells from patients expressing more than 50 x 10(3) CD20 molecules per cell, and directly correlated with the number of CD20 molecules per cell. Preincubation with anti-CD59 increased the cytotoxic effect of rituximab and sensitized cells from nonsensitive cases. Neither cleavage of poly-ADP ribose polymerase (PARP) nor activation of caspase-3 was observed in R-CDC. In addition, no cells with a hypodiploid DNA content were detected and R-CDC was not prevented by a broad-spectrum caspase inhibitor, suggesting a caspase-independent mechanism. Incubation with rituximab in the presence of AB serum induced a rapid and intense production of reactive oxygen species (ROS). R-CDC was blocked by the incubation of cells with N-acetyl-L-cysteine (NAC) or Tiron, 2 ROS scavengers, indicating that the cytotoxic effect was due to the generation of superoxide (O) radicals. In conclusion, the results of the present study suggest that CD20, CD59, and complement have a role in the in vitro cytotoxic effect of rituximab, which is mediated by a caspase-independent process that involves ROS generation.

Adult↗
PubMed2001

Molecular characterization and expression of a novel human leukocyte cell-surface marker homologous to mouse Ly-9.

Ly-9 is a mouse cell-surface glycoprotein that is selectively expressed on thymocytes and on mature T and B lymphocytes. Ly-9 belongs to the CD2 subset of the immunoglobulin superfamily, an emerging family of cell signaling receptors. Recently, a partial human Ly-9 complementary DNA (cDNA) sequence has been described. Full-length cDNA clones were isolated that included the initiation codon, the sequence encoding the full signal peptide, and 14 amino acids more in the cytoplasmic domain than in the previously reported clone. The predicted extracellular domain of human Ly-9 contains 4 immunoglobulinlike domains, similar to those in mouse Ly-9. Northern blot analysis revealed that the human Ly-9 messenger RNA (2.6 kb) is expressed predominantly in lymph node, spleen, thymus, and peripheral blood leukocytes. Four monoclonal antibodies (mAbs) were raised against human Ly-9 by immunizing mice with the pre-B-cell line 300.19 stably transfected with human Ly-9 full-length cDNA. These mAbs strongly stained the surfaces of cells transfected with human Ly-9 cDNA but not of untransfected cells. Human Ly-9 expression was restricted to T and B lymphocytes and thymocytes, with the highest levels of expression on CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes. Monocytes, granulocytes, platelets, and red blood cells were uniformly negative for Ly-9. These mAbs immunoprecipitated major polypeptides of 120 kd from the transfected cells and 120 kd and 100 kd from B-cell line Daudi, probably because of the cell-surface-expressed isoforms. These data demonstrate that human Ly-9 is a new marker for the study of normal and malignant leukocytes. (Blood. 2001;97:3513-3520)

Amino Acid Sequence↗
PubMed2001

Prognostic features and outcome in patients with diffuse large B-cell lymphoma who do not achieve a complete response to first-line regimens.

BACKGROUND: The current study was conducted to analyze the outcome and prognostic factors of patients with diffuse large B-cell lymphoma (DLCL) who did not achieve a complete response (CR) to first-line treatment. METHODS: The current study was comprised of 83 patients (43 males and 40 females with a median age of 62 years) who did not achieve a CR (58 of whom had primary refractory disease and 25 of whom achieved a partial response) with initial treatment (doxorubicin-containing regimens in 87% of cases) from a series of 239 patients consecutively diagnosed with DLCL at a single institution. Initial variables, response to therapy, and salvage treatment were analyzed to predict survival. RESULTS: Compared with patients who achieved a CR, nonresponders or partial responders more frequently were of advanced age and had a poor performance status (PS), B-symptoms, advanced stage of disease, bone marrow infiltration, increased serum lactate dehydrogenase, and a high-risk International Prognostic Index. Among the 58 patients with primary refractory disease, 18 died during initial treatment due to toxicity (14 patients) or disease progression (4 patients). The main variables predicting early death were a poor PS, age > 60 years, and an immunoblastic DLCL subtype. Twenty-five of these 58 patients were able to receive salvage regimens, with only 1 of them achieving a CR. The median survival for this group of patients was 10 months. With regard to those patients achieving a partial response, 18 of the 25 patients received further therapy with 28% of them achieving a CR. The median survival was 23 months. The degree of the response was found to be the only significant variable with which to predict survival, with 2-year survival rates of 4% and 40%, respectively, for patients with primary refractory disease and patients who achieved a partial response. CONCLUSIONS: The prognosis of patients with primarily refractory DLCL is extremely unfavorable, whereas that of patients who achieve a partial response is slightly better. The inclusion of these patients in experimental trials is limited due to their tendency to be of an older age and to have a poor general status.

Adolescent↗
PubMed2001

BMI-1 gene amplification and overexpression in hematological malignancies occur mainly in mantle cell lymphomas.

The BMI-1 gene is a putative oncogene belonging to the Polycomb group family that cooperates with c-myc in the generation of mouse lymphomas and seems to participate in cell cycle regulation and senescence by acting as a transcriptional repressor of the INK4a/ARF locus. The BMI-1 gene has been located on chromosome 10p13, a region involved in chromosomal translocations in infant leukemias, and amplified in occasional non-Hodgkin's lymphomas (NHLs) and solid tumors. To determine the possible alterations of this gene in human malignancies, we have examined 160 lymphoproliferative disorders, 13 myeloid leukemias, and 89 carcinomas by Southern blot analysis and detected BMI-1 gene amplification (3- to 7-fold) in 4 of 36 (11%) mantle cell lymphomas (MCLs) with no alterations in the INK4a/ARF locus. BMI-1 and p16INK4a mRNA and protein expression were also studied by real-time quantitative reverse transcription-PCR and Western blot, respectively, in a subset of NHLs. BMI-1 expression was significantly higher in chronic lymphocytic leukemia and MCL than in follicular lymphoma and large B cell lymphoma. The four tumors with gene amplification showed significantly higher mRNA levels than other MCLs and NHLs with the BMI-1 gene in germline configuration. Five additional MCLs also showed very high mRNA levels without gene amplification. A good correlation between BMI-1 mRNA levels and protein expression was observed in all types of lymphomas. No relationship was detected between BMI-1 and p16INK4a mRNA levels. These findings suggest that BMI-1 gene alterations in human neoplasms are uncommon, but they may contribute to the pathogenesis in a subset of malignant lymphomas, particularly of mantle cell type.

Cyclin-Dependent Kinase Inhibitor p16↗
PubMed2001

Expression of cathepsins B and S in the progression of prostate carcinoma.

Cathepsins B and S (CatB, CatS) are lysosomal cysteine proteases which, among other functions, appear to play a role in cancer progression in different tumor models due to their matrix-degrading properties. To investigate their possible involvement in the development of prostate carcinoma, we immunohistochemically analyzed CatB and CatS in 38 primary human prostatic adenocarcinomas, as well as concomitant high-grade prostatic intra-epithelial neoplasia, nodular hyperplasia and normal tissue. CatB expression was observed in 28 (74%) and CatS in 32 (84%) carcinomas, being concomitant in 24 cases (63%). High-grade intra-epithelial neoplasia expressed CatB in 20/23 cases (87%), and a similar result was obtained for CatS, with expression of both coinciding in 18 cases (78%). In non-neoplastic tissue, strong expression of both proteases was observed in macrophages, inflamed glands and transitional metaplasia, whereas atrophic glands and basal cells of normal glands displayed intense CatB positivity. We conclude that CatB and CatS are often expressed together in neoplastic prostatic cells from pre-invasive to invasive and clinically detectable stages, suggesting a putative role in local invasion, though other functions cannot be ruled out.

Adenocarcinoma↗
PubMed2001

Small-vessel vasculitis surrounding a spared temporal artery: clinical and pathological findings in a series of twenty-eight patients.

OBJECTIVE: Occasionally, a temporal artery biopsy reveals small-vessel vasculitis (SVV) surrounding a spared temporal artery, the significance of which is unclear. We analyzed the final diagnosis in a series of patients with this condition and tried to identify histopathologic features with potential usefulness in predicting the ultimate diagnosis. METHODS: We performed a clinical and histopathologic review of 28 patients in whom SVV surrounding a spared temporal artery was the first histologic finding that led to the diagnosis of vasculitis. For comparison purposes, we analyzed the pattern of small vessel involvement in 30 patients with biopsy-proven giant cell arteritis (GCA). RESULTS: GCA was considered the most likely diagnosis in 12 patients, based on the absence of clinical evidence of additional organ involvement and normal findings on muscle biopsy and electrophysiologic study. Three patients had systemic necrotizing vasculitis (SNV), based on the demonstration of typical lesions on subsequent muscle, nerve, or kidney biopsy. After extensive evaluation, 4 patients remained unclassifiable. Nine patients were incompletely studied. Fibrinoid necrosis was significantly more frequent in patients with SNV (P = 0.0022), whereas involvement of vasa vasorum was more frequent in patients classified as having GCA (P = 0.022). No differences in the pattern of small vessel involvement were found in patients with SVV surrounding a spared temporal artery who were classified as having GCA compared with patients with biopsy-proven GCA. Granulocytes were observed at similar frequency in all conditions. CONCLUSION: SVV may be the only abnormal feature in a temporal artery biopsy and the only histologic evidence of vasculitis. The diagnosis of GCA can be reasonably established in most of these patients when there is no apparent evidence of additional organ involvement. However, when fibrinoid necrosis is observed or the temporal artery vasa vasorum are not involved, SNV must be extensively excluded.

Adult↗
PubMed2001

Tissue macroarrays ("microchops") for gene expression analysis.

We describe a simple system of tissue arraying with multiple tissue fragments obtained with a biopsy punch from selected areas of paraffin blocks. The new blocks thus constructed allow multiple tissue sections in which the uniform shape of the fragments coupled with a geometrical display and a significant amount of tissue per case allows a dependable, cost-effective way to screen tumors or other kinds of tissues with techniques such as immunohistochemistry. This system avoids the disadvantages of previous laborious methods of tissue arraying, such as expensive equipment and scarce tissue sampling, and it can be implemented in any institution with minimal cost and elaboration.

DNA, Neoplasm↗
PubMed2001

Cutaneous lymphocyte-associated antigen (CLA) expression in a lymphoblastoid mantle cell lymphoma presenting with skin lesions. Comparison with other clinicopathologic presentations of mantle cell lymphoma.

BACKGROUND: Cutaneous lymphocyte-associated antigen (CLA) is a lymphocyte homing receptor selectively expressed by T cells of the cutaneous immune system and their malignant counterpart, that is to say, cutaneous T-cell lymphomas. However it is absent in the vast mayority of other T-cell malignancies and B-cell lineage lymphomas irrespective on primary tumor site. METHODS: Expression of CLA was investigated on six cases of mantle cell lymphoma (MCL) which differed in their histopathological subtype (typical or blastic) and their tendency to infiltrate skin and/or central nervous system (CNS). RESULTS: CLA immunostaining on neoplastic cells was only observed in a 61-year-old female suffering from a lymphoblastoid MCL which clinically presented with specific skin lesions and further developped CNS disease. In this patient, coexpression of CLA with MCL markers (CD20 and CD5) was confirmed by conventional immunohistochemistry and double immunofluorescence studies. CONCLUSIONS: To our knowledge, CLA immunoreactivity on B-cell lymphomas has not beeen previously reported. The expression of this skin-related adhesion molecule on malignant MCL cells could explain the clinical behavior of our case which presented and relapsed with cutaneous lesions. However, CLA seems not to be a MCL marker nor a CNS-related adhesion molecule. The authors review the clinical and histopathological characteristics of MCL-specific skin lesions and their diagnostic clues based on cell morphology, immunohistochemistry and molecular investigations.

Adult↗
PubMed2001

Molecular characterization of a new ALK translocation involving moesin (MSN-ALK) in anaplastic large cell lymphoma.

The majority of anaplastic large cell lymphomas (ALCL) are associated with chromosomal abnormalities affecting the anaplastic lymphoma kinase (ALK) gene which result in the expression of hybrid ALK fusion proteins in the tumor cells. In most of these tumors, the hybrid gene comprises the 5' region of nucleophosmin (NPM) fused in frame to the 3' portion of ALK, resulting in the expression of the chimeric oncogenic tyrosine kinase NPM-ALK. However, other variant rearrangements have been described in which ALK fuses to a partner other than NPM. Here we have identified the moesin (MSN) gene at Xq11-12 as a new partner of ALK in a case of ALCL which exhibited a distinctive membrane-restricted pattern of ALK labeling. The hybrid MSN-ALK protein had a molecular weight of 125 kd and contained an active tyrosine kinase domain. The unique membrane staining pattern of ALK is presumed to reflect association of moesin with cell membrane proteins. In contrast to other translocations involving the ALK gene, the ALK breakpoint in this case occurred within the exonic sequence coding for the juxtamembrane portion of ALK. Identification of the genomic breakpoint confirmed the in-frame fusion of the whole MSN intron 10 to a 17 bp shorter juxtamembrane exon of ALK. The breakpoint in der(2) chromosome showed a deletion, including 30 bp of ALK and 36 bp of MSN genes. These findings indicate that MSN may act as an alternative fusion partner for activation of ALK in ALCL and provide further evidence that oncogenic activation of ALK may occur at different intracellular locations.

Adolescent↗
PubMed2001

Differential expression of cdc25 cell-cycle-activating phosphatases in human colorectal carcinoma.

cdc25 is a family of cell-cycle phosphatases that activate the cyclin-dependent kinases. cdc25A and B, but not C, have oncogenic potential in vitro. In this study, we analyzed the possible implication of cdc25 genes in the progression of colorectal tumors. RNA and DNA were extracted from 34 paired tumor and normal colorectal tissues and examined by Northern blot, RT-PCR, and Southern blot, respectively. Protein expression was analyzed by Western blot in a subset of normal and tumor samples. The expression levels were correlated with the clinicopathologic characteristics and survival of the patients. cdc25B mRNA was overexpressed in 19 carcinomas (56%). A significant correlation was observed between high cdc25B mRNA levels and the relapse-free, overall, and cancer-related survival of the patients. The cdc25B2 splicing variant was detected in 27 carcinomas (79%) but only in 9 normal samples (26%) and was associated with the grade of the differentiation of the tumors. cdc25A mRNA was overexpressed in four tumors (12%) and cdc25C1 mRNA was overexpressed in nine tumors (26%). A new cdc25C2 splicing variant lacking exon 4 and 5 was identified in all of the tumors and in 56% of the normal samples. No amplifications or gene rearrangements of these genes were detected. In conclusion, these findings indicate that cdc25 isoforms and splicing variants are differentially regulated in colorectal carcinomas and may participate in the development of these tumors. Additionally, the correlation between cdc25B mRNA levels and the survival of the patients also suggest that the cdc25B isoform may be involved in the progression of the disease.

Adult↗
PubMed2001

Stem cell transplantation for chronic lymphocytic leukemia: different outcome after autologous and allogeneic transplantation and correlation with minimal residual disease status.

The clinical outcome and its correlation with the status of minimal residual disease (MRD) was analyzed in 26 patients with chronic lymphocytic leukemia (CLL) undergoing stem cell transplantation. All patients having received autotransplant (n = 14) achieved CR which was MRD(-) in nine patients (64%) and MRD(+) in five. With a median follow-up of 26.5 months (range, 12-52), four of the five MRD(+) patients relapsed at 9, 15, 17 and 18 months after transplant, respectively. In contrast, only two patients of the nine MRD(-) patients have relapsed at 15 and 38 months (P = 0.02), and four became MRD(+) at 6, 12, 30, and 42 months after transplantation, respectively. Of the 12 patients that were allografted, three (25%) died in the early post-transplant period, one had resistant disease, and eight (67%) achieved CR. Among the latter, no evidence of MRD post-transplantation was observed in five cases, while a delayed clearance of MRD (up to 22 months after transplantation) was seen in two, and a persistent positivity of MRD after transplant was detectable in another patient until last follow-up (12 months). After a median follow-up of 43 months (range, 15-106), none of the responding patients had clinical or MRD relapse. These results show that in CLL the probability of achieving sustained MRD(-) CR is higher with allogeneic than with autologous transplants, and confirm the value of MRD assessment in the follow-up of patients transplanted for CLL.

Graft vs Host Disease↗
PubMed2001

Blastic natural killer cell leukemia/lymphoma presenting as overt leukemia.

Blastic natural killer (NK)-cell leukemia/lymphoma is a neoplasm of NK origin with aggressive behavior. The disease affects mainly elderly people and often presents with skin lesions and overt leukemia. Blastic morphology, an NK-cell immunophenotype, and lack of association with Epstein-Barr virus are the clues for the diagnosis. We report herein, the case of a patient with a blastic NK-cell leukemia/lymphoma with overt leukemia at diagnosis, who achieved a complete response after CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) chemotherapy. However, the patient relapsed a few months later and died due to disease progression. Cases of blastic NK-cell leukemia/ lymphoma previously reported are briefly reviewed.

Adolescent↗
PubMed2001

Microsatellite instability analysis in typical and progressed mantle cell lymphoma and B-cell chronic lymphocytic leukemia.

BACKGROUND AND OBJECTIVES: Microsatellite instability (MSI) is characterized by tumor-associated alterations in the germline size of microsatellite repeats caused by a reduced efficacy of the DNA mismatch repair machinery. The aim of this study was to investigate the presence of MSI in a number of cases of indolent and aggressive mantle cell lymphoma (MCL) and B-cell chronic lymphocytic leukemia (B-CLL) to determine its possible role in the initial development and progression of these disorders. DESIGN AND METHODS: We examined the presence of MSI in 28 B-CLL, 24 typical and 4 transformed B-CLL (Richter's syndrome) and 29 MCL, 19 typical and 10 blastoid variants by using a panel of 10 microsatellite markers and analyzed them using an AbiPrism 310 DNA sequencer. Fisher's exact test was used to compare categorical variables and Mann-Whitney's U-test for continuous variables. RESULTS: MSI alterations were not observed in any case of MCL or Richter's syndrome and in only three (13%) patients with typical B-CLL. Two of these patients also had loss of heterozygosity in one of the 10 sites examined. These patients presented with a more advanced stage, diffuse bone marrow involvement, and poorer performance status than patients without these alterations. INTERPRETATION AND CONCLUSIONS: These findings indicate that MSI is not involved in the pathogenesis or progression of B-CLL and MCL but may appear in a small subset of patients with advanced B-CLL.

Adult↗
PubMed2000

Hybrid chemotherapy consisting of cyclophosphamide, vincristine, procarbazine, prednisone, doxorubicin, bleomycin, and vinblastine (C-MOPP/ABV) as first-line treatment for patients with advanced Hodgkin disease.

BACKGROUND: Combination chemotherapy, including hybrid regimens, is the standard treatment for patients with advanced Hodgkin disease (HD). Although a prolonged complete response (CR) is achieved in up to 70-80% of patients, long term complications, such as secondary leukemia, are of concern. Cyclophosphamide, vincristine, procarbazine, prednisone, doxorubicin, bleomycin, and vinblastine (C-MOPP/ABV) is a hybrid chemotherapy in which cyclophosphamide is substituted for mechlorethamine, an agent that has been implicated as the cause of secondary malignancies. METHODS: Seventy-three patients (37 males and 36 females; median age, 35 years) diagnosed with Stage III or IV HD or Stage II with bulky disease, B-symptoms, elevated erythrocyte sedimentation rate, or hilar adenopathy were treated with 8 courses of C-MOPP/ABV at a single institution during a 6-year period. Radiotherapy (RT) was administered when bulky disease or residual masses were present. Endpoints of the study were response to therapy, failure free survival (FFS), overall survival (OS), and toxicity. RESULTS: Sixty-five patients (90%) received the 8 planned courses, with 49 of them (70%) receiving the full prescribed doses. After chemotherapy, 57 patients (78%) reached CR. Seven additional patients who achieved partial response (PR) reached CR after complementary radiotherapy, with an overall CR rate of 88%. The median follow-up was 31 months. Twelve patients relapsed; the 4-year FFS was 66% (95% CI, 54-78%). Two patients died during treatment because of sepsis and four due to disease progression. The 4-year OS was 92% (95% CI, 86-98%). Age > 60 years and bone marrow involvement were related to severe infectious complications. No late toxicity was reported. CONCLUSIONS: C-MOPP/ABV induces CR with acceptable toxicity in a high proportion of advanced HD patients.

Adult↗
PubMed2000

cdc25a and the splicing variant cdc25b2, but not cdc25B1, -B3 or -C, are over-expressed in aggressive human non-Hodgkin's lymphomas.

cdc25 is a family of phosphatases that activate the cyclin-dependent kinases at different points of the cell cycle. cdc25A and -B, but not -C, have been shown to have oncogenic potential. Three different splicing variants of the cdc25B gene, cdc25B1, -B2 and -B3, have also been identified. Experimental studies suggest that cdc25B2 may be more active in vivo than cdc25B3 and -B1, but the relative expression of these splicing variants in human tumors is not known. In this study, we have analyzed the expression of cdc25A, -B1, -B2, -B3 and -C mRNA in 9 non-neoplastic lymphoid samples, 89 non-Hodgki&ngrave;s lymphomas and 9 hematological cancer cell lines by semi-quantitative RT-PCR. cdc25A, -B and -C protein expression was examined by Western blot. Normal peripheral blood lymphocytes and reactive tissues expressed cdc25B1 and -B3 mRNA and very low or undetectable levels of cdc25A, -B2 and -C. High levels of cdc25A and cdc25B2 were found in 35% and 39% of the tumors, respectively, and they were more frequently observed in aggressive than in indolent lymphomas. cdc25B1 and -B3 splice variants were detected in virtually all tumors, and no significant differences were found between high- and low-grade lymphomas. cdc25A and -B protein expression was also higher in aggressive than in indolent lymphomas. cdc25C expression was relatively low in virtually all cases. In conclusion, these findings suggest that cdc25A and -B2, but not cdc25B1, -B3 and -C, are over-expressed in a relatively large number of malignant lymphomas and may participate in the pathogenesis of aggressive variants.

Blotting, Western↗