Biomedical subjects

L De Zen

Publications and source records attributed to L De Zen.

6 recordsLinked to original sources

PubMed2004

CD99 expression in T-lineage ALL: implications for flow cytometric detection of minimal residual disease.

Expression of CD99 is higher on immature than on mature T cells. We postulated that this marker could be used to assess minimal residual disease (MRD) in T-lineage acute lymphoblastic leukemia (T-ALL). In diagnostic bone marrow (BM) samples from 27 children with T-ALL, expression of CD99 on leukemic lymphoblasts by flow cytometry was in median 7.7 times higher than on normal T lymphocytes from within the same sample. In 85% of cases, leukemic MFI values were higher than the mean MFI+2 s.d. of normal populations. We applied CD99 to study MRD in 39 follow-up samples from 15 consecutive T-ALL patients, and compared the results with those obtained with the well-established MRD-marker terminal deoxynucleotidyl transferase (TdT). Either antibody was combined in four-color flow cytometry with CD7, surfaceCD3, and cytoplasmicCD3. We found that CD99 was a valid complement to TdT in quantifying T-ALL MRD. Given a considerable interpatient variability, CD99 could be favorably used in nine patients, and TdT in other five patients. Both approaches showed a similar very low nonspecific background throughout 12 weeks from diagnosis (in median 0.002% of nucleated BM cells in patients with non-T ALL). We conclude that CD99 is a highly informative tool for MRD detection in T-ALL, bearing the advantage of surface expression in contrast to TdT.

12E7 Antigen↗

PubMed2003

Computational analysis of flow-cytometry antigen expression profiles in childhood acute lymphoblastic leukemia: an MLL/AF4 identification.

Precursor B-acute lymphoblastic leukemia (pB-ALL) is a heterogeneous disease and multiparameter flow cytometry, molecular genetics, and cytogenetic studies have all contributed to classification of subgroups with prognostic significance. Recently, gene expression microarray technology has been used to investigate lymphoblastic leukemias, demonstrating that known and novel pB-ALL subclasses can be separated on the basis of gene expression profiles. The strength of microarray technique lays in part in the multivariate nature of the expression data. We propose a parallel multiparametric approach based on immunophenotypic flow-cytometry expression data for the analysis of leukemia patients. Specifically, we tested the potential of this approach on a data set of 145 samples of pediatric pB-ALL that included 46 samples positive for mixed lineage leukemia (MLL) translocations (MLL+) and 99 control pB-ALLs, negative for this translocation (MLL-). The expression levels of 16 marker proteins have been monitored by four-color flow cytometry using a standardized diagnostic panel of antibodies. The protein expression database has been then analyzed using those univariate and multivariate computational techniques normally applied to mine and model large microarray data sets. Marker protein expression profiling not only allowed separating pB-ALL cases with an MLL rearrangement from other ALLs, but also demonstrates that MLL+ leukemias constitute a heterogeneous group in which MLL/AF4 leukemias represent a homogenous subclass described by a specific expression fingerprint.

Adolescent↗

PubMed2002

Intensive chemotherapy for children and young adults with metastatic primitive neuroectodermal tumors of the soft tissue.

The MMT4 study was designed to explore an intensive chemotherapy regimen (MMT4-89) and the role of high-dose melphalan (MMT4-91) in children with metastatic soft tissue sarcoma, including extraosseous peripheral neuroectodermal tumor (PNET). Thirty-one patients with PNET were treated between 1989 and 1995 (11 according to MMT4-89 and 20 according to MMT4-91). Chemotherapy consisted of four CEVAIE cycles, each including three 3-week courses: CEV (carboplatin 500 mg/m(2), epirubicin 150 mg/m(2), vincristine 1.5 mg/m(2)), IVA ifosfamide 9 g/m(2), actinomycin 1.5 mg/m(2), vincristine 1.5 mg/m(2)), IVE (ifosfamide 9 g/m(2), etoposide 600 mg/m(2), vincristine 1.5 mg/m(2)). In MMT4-91 the fourth CEVAIE was replaced with melphalan 200 mg/m(2) with stem cell rescue. The CEV combination was evaluated as a window study. Surgery followed the second cycle. Radiotherapy was administered to post-surgical residual disease. The response rate was 55% after CEV, rising to 80% after the first CEVAIE. Twenty-five patients achieved complete remission (CR). Overall, the 5-year EFS was 22.6%: 36.4% and 15% for patients treated according to MMT4-89 and MMT4-91, respectively (P = 0.3). Local control was achieved in 77% of irradiated patients vs 45% of non-irradiated. Age >10 years was associated with significantly poorer outcome (P = 0.04). In conclusion, despite the high CR rate, intensive chemotherapy with or without high-dose melphalan appeared to have little impact on the survival of patients with metastatic extraosseus PNET.

Adolescent↗

PubMed2001

New methodologic approaches for immunophenotyping acute leukemias.

BACKGROUND AND OBJECTIVES: Flow cytometry is nowadays the preferred method for immunophenotypic identification, enumeration and characterization of blast cells at diagnosis. Despite widespread application of standardized protocols, inter-laboratory reproducibility has still not been achieved. The complexity of diagnosis and evaluation of minimal residual disease, in immunophenotyping acute leukemia, demands the use of a test that provides all the necessary information. DATA SOURCES AND METHODS: The information given here is derived from the experience of the authors and from literature files. The most relevant studies with adequate conclusions were considered. We report on the current status of multiparametric immunophenotyping using simultaneous three and four-color staining and the applications of this technique. RESULTS: Multiparametric immunophenotyping is a powerful method for achieving a clear discrimination between normal and pathologic cells. The specific identification of leukemic cells by immunologic gating forms the basis for immunophenotypic diagnosis, classification as well as prognostic evaluation of patients with acute leukemias. The performance of the procedure with regards to the panels of reagents and the analytic processes, is necessarily different in lymphoblastic and myeloblastic leukemias, since the diagnostic questions are different. Phenotypic information should be specifically provided for the blast cells and antigen expression should preferably be reported in quantitative units and CV. This would allow a standardized cross evaluation of immunophenotypic results between different investigators and laboratories. INTERPRETATION AND CONCLUSIONS: Recent reports indicate that phenotypic aberrations reflect genetic abnormalities of leukemic cells and therefore their definition and identification is of clinical relevance not only for minimal residual disease monitoring but also for subclassifying acute myeloid and lymphocytic leukemias.

Acute Disease↗

PubMed2000

Quantitative multiparametric immunophenotyping in acute lymphoblastic leukemia: correlation with specific genotype. I. ETV6/AML1 ALLs identification.

The t(12;21)(p13;q22) fusion gene is the most frequent genetic lesion described in precursor B cell acute lymphoblastic leukemia (ALL) of childhood occurring in a quarter of cases. This gene rearrangement is associated with a good outcome presenting a high response rate to chemotherapy. In spite of its potential clinical relevance, the t(12;21) translocation usually goes undetected with conventional cytogenetic procedures. In the present study we utilized an objective flow cytometric approach (multiparametric quantitative analysis) for the phenotypic characterization of this type of ALL. We studied a total of 74 precursor B-ALL children, including 21 t(12;21)+ and 53 t(12;21)- cases. Our results show that the t(12;21)(p13;q22)+ ALLs display a higher intensity of CD10 (P = 0.0016) and HLADR (P = 0.005) expression together with lower levels of the CD20 (P = 0.01), CD45 (P = 0.01), CD135 (P = 0.003) and CD34 (P = 0.03) antigens as compared to the t(12;21) cases. Moreover, as regards CD34 expression, we observed a more heterogeneous antigen expression within individual patients with higher coefficients of variation (median of 202 vs 88, P = 0.0001). A multi-variate analysis disclosed that with the immunophenotypic approach used identification of t(12;21)+ cases can be achieved with a sensitivity of 86% and a specificity of 100%. We conclude that childhood precursor B-ALL carrying the t(12;21) translocation display characteristic phenotypic features which could provide a rapid, simple, sensitive and specific screening method to select for those cases that should undergo confirmatory molecular analysis.

Antigens, CD↗

PubMed1997

Clinical relevance of DNA ploidy and proliferative activity in childhood rhabdomyosarcoma: a retrospective analysis of patients enrolled onto the Italian Cooperative Rhabdomyosarcoma Study RMS88.

PURPOSE: Evaluation of the possible clinical relevance of DNA ploidy and proliferative activity assessed as S-phase fraction (SPF) in childhood rhabdomyosarcoma (RMS). PATIENTS AND METHODS: We conducted a retrospective study on 59 RMS patients enrolled onto the ICS-RMS88 protocol (seven botryoid, 35 embryonal, and 17 alveolar RMS), for which formalin-fixed paraffin-embedded (FFPE) tissue was available. Nuclear suspensions for cytometric investigation were obtained using a mechanical disaggregation. Tumors were distinguished according to their DNA index (DI) value as follows: diploid (0.9 < DI < 1.1), hyperdiploid (1.1 < or = DI < 1.8 or DI > or = 2.2), and tetraploid (1.8 < or = DI < 2.2); for analysis of SPF, a cutoff value of 14% was used. RESULTS: DNA histograms were diploid in 19 (33%) cases, hyperdiploid in 29 (49%), and tetraploid in 10 (32%). One patient showed both a hyperdiploid and a tetraploid peak. The 5-year overall survival (OS) rate by ploidy status was 73% in hyperdiploid patients as compared with 33% and 25% in diploid and tetraploid patients, respectively (P = .0012). A striking difference emerged when the 5-year OS for the combined diploid and tetraploid RMS groups was compared with survival of the hyperdiploid RMS group: 30% versus 73%, respectively (P = .0006). In addition, the SPF was prognostically relevant: 5-year OS by SPF less than or greater than 14% was 70% and 36%, respectively (P = .009). Multivariate analysis confirmed the importance of DNA content (P = .0006) and SPF (P = .034) in predicting survival. CONCLUSION: These findings confirm that ploidy and SPF are important new prognostic factors that are able to identify selected groups of patients at high risk of treatment failure, even if the tumor's presentation is favorable according to standard criteria.

Adolescent↗