Clinical significance of ZAP-70 protein expression in B-cell chronic lymphocytic leukemia.
Del Principe MI, Del Poeta G, Buccisano F, Maurillo L, Venditti A, Zucchetto A, Marini R, Niscola P, Consalvo MA, Mazzone C, Ottaviani L, Panetta P, Bruno A, Bomben R, Suppo G, Degan M, Gattei V, de Fabritiis P, Cantonetti M, Lo Coco F, Del Principe D, Amadori S. Cattedra di Ematologia, Universita Tor Vergata, Ospedale S Eugenio, Via Fiume Giallo, 430 MA, 00144 Roma, Rome, Italy.

The clinical course of B-cell chronic lymphocytic leukemia (B-CLL) is variable, and novel biologic parameters need to be added to the clinical staging systems to predict an indolent or aggressive outcome. We investigated the 70-kDa zeta-associated protein (ZAP-70), CD38, soluble CD23 (sCD23), and cytogenetics in 289 patients with B-CLL. Both a shorter progression-free survival (PFS) and overall survival (OS) were observed in ZAP-70(+) (P < .001), in CD38(+) (P < .001) and in sCD23(+) patients (P < .001 and P = .013, respectively). ZAP-70(+)CD38(+) or ZAP-70(+) patients with an unmutated IgV(H) status showed both a shorter PFS (P < .001) and OS (P < .001 and P < .001, respectively) as compared with ZAP-70(-)/CD38(-) or ZAP-70(-) patients with mutated IgV(H) genes. Discordant patients showed an intermediate outcome. Note, ZAP-70(+) patients even if CD38(-) or mutated showed a shorter PFS, whereas ZAP-70(-) patients even if CD38(+) or unmutated had a longer PFS. Furthermore, ZAP-70 positivity was associated with a shorter PFS both within normal karyotype (P < .001) and within the poor-risk cytogenetic subset (P = .02). The predictive value of ZAP-70 expression was confirmed in multivariate analysis. Thus, ZAP-70 protein determined by flow cytometry improves the prognostic significance of cytogenetics and appears to be a better predictor of outcomes than IgV(H) gene mutational status. On this line, we recommend and are also interested in conducting a prospective randomized trial of early intervention versus observation for ZAP-70(+) patients.

PMID: 16601244 [PubMed - indexed for MEDLINE]