Background: Flow cytometry allows specific assessment of the expression of ZAP-70, a promising new prognostic factor in B-cell chronic lymphocytic leukemia (B-CLL), but suffers from a lack of multicenter standardization. Design and Methods: An optimized method for direct detection of ZAP-70 in flow cytometry was tested in a multicenter fashion. Adapted for frozen cells, this method includes a normalization step by addition of B cells from a pool of peripheral blood mononuclear cells collected from normal donors. ZAP-70 expression levels were assessed for 153 patients with typical B-cell chronic lymphocytic leukemia chronic lymphocytic leukemia. Results were expressed as the ratio of ZAP-70 mean fluorescence intensity between B-CLL cells and normal B cells. Results: The statistically optimized cut-off of ZAP-70 positivity was a ratio of 1.4. Concordance between ZAP-70 and CD38 expression was 67%. Concordance between the mutational status of IgVH genes and ZAP-70 or CD38 expression was 87% and 65%, respectively. ZAP-70 was significantly expressed in 28%, 54% and 61% of patients with Binet stages A, B and C B-cell chronic lymphocytic leukemia, respectively (p=0.008). The absence of ZAP-70 expression was associated with isolated del(13q14), a cytogenetic abnormality with a good prognosis, while most patients with the del(17p13) poor prognosis cytogenetic marker expressed ZAP-70 (p<10-5). ZAP-70 expression was not related to the other poor prognosis cytogenetic abnormality del(11q22.3) nor to trisomy 12. Conclusions: This new technique provides highly reliable results well correlated with the mutational status of IgVH genes, CD38 expression, Binet stage and cytogenetic abnormalities. This robust discriminative technique appears of particular interest for routine diagnosis and assessment of ZAP-70 expression in large, prospective, multicenter therapeutic trials.

A distinctive trascriptional profile characterizes the chromosome 17p loss in B-cell chronic lymphocytic leukemia / S. Fabris, L. Mosca, K. Todoerti, G. Cutrona, S. Matis, M. Colombo, L. Agnelli, M. Lionetti, D. Intini, M. Gentile, M. Mauro, V. Callea, G. Festini, S. Molica, G. Lambertenghi Deliliers, F. Morabito, M. Ferrarini, A. Neri. - In: HAEMATOLOGICA. - ISSN 0390-6078. - 93:suppl. 1(2008 Jun), pp. 215-215. ((Intervento presentato al 13. convegno Congress of the European hematology association tenutosi a Copenhagen nel 2008.

A distinctive trascriptional profile characterizes the chromosome 17p loss in B-cell chronic lymphocytic leukemia

S. Fabris
Primo
;
K. Todoerti;L. Agnelli;M. Lionetti;D. Intini;G. Lambertenghi Deliliers;A. Neri
Ultimo
2008-06

Abstract

Background: Flow cytometry allows specific assessment of the expression of ZAP-70, a promising new prognostic factor in B-cell chronic lymphocytic leukemia (B-CLL), but suffers from a lack of multicenter standardization. Design and Methods: An optimized method for direct detection of ZAP-70 in flow cytometry was tested in a multicenter fashion. Adapted for frozen cells, this method includes a normalization step by addition of B cells from a pool of peripheral blood mononuclear cells collected from normal donors. ZAP-70 expression levels were assessed for 153 patients with typical B-cell chronic lymphocytic leukemia chronic lymphocytic leukemia. Results were expressed as the ratio of ZAP-70 mean fluorescence intensity between B-CLL cells and normal B cells. Results: The statistically optimized cut-off of ZAP-70 positivity was a ratio of 1.4. Concordance between ZAP-70 and CD38 expression was 67%. Concordance between the mutational status of IgVH genes and ZAP-70 or CD38 expression was 87% and 65%, respectively. ZAP-70 was significantly expressed in 28%, 54% and 61% of patients with Binet stages A, B and C B-cell chronic lymphocytic leukemia, respectively (p=0.008). The absence of ZAP-70 expression was associated with isolated del(13q14), a cytogenetic abnormality with a good prognosis, while most patients with the del(17p13) poor prognosis cytogenetic marker expressed ZAP-70 (p<10-5). ZAP-70 expression was not related to the other poor prognosis cytogenetic abnormality del(11q22.3) nor to trisomy 12. Conclusions: This new technique provides highly reliable results well correlated with the mutational status of IgVH genes, CD38 expression, Binet stage and cytogenetic abnormalities. This robust discriminative technique appears of particular interest for routine diagnosis and assessment of ZAP-70 expression in large, prospective, multicenter therapeutic trials.
B-cell chronic lymphocytic leukemia; CD38; Prognosis; ZAP-70
Settore MED/15 - Malattie del Sangue
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/49260
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