Annals of Oncology Advance Access originally published online on March 8, 2006
Annals of Oncology 2006 17(4):683-690; doi:10.1093/annonc/mdj120
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© 2006 European Society for Medical Oncology
The clinical significance of ZAP-70 and CD38 expression in B-cell chronic lymphocytic leukaemia
ski2
sik-Szczepanek1ska1Departments of 1 Haemato-oncology and 2 Clinical Immunology, Medical University of Lublin, Poland; 3 3rd Department of Internal Medicine, University of Ulm, Germany
* Correspondence to: Dr I. Hus, Department of Haematology, Medical University of Lublin, 20–081 Lublin, Staszica 11, Poland. Tel: +48 81 53 45 468; Fax: +48 81 53 45 605; E-mail: iwohus{at}wp.pl
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Abstract |
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Background: B-cell chronic lymphocytic leukaemia (B-CLL) is a disease with a highly variable clinical course; some patients never need treatment, while others require intensive treatment early after diagnosis. Recently, some new prognostic factors, such as IgVH mutational status, ZAP-70 and the expression of CD38 in leukaemic cells were introduced to identify attenuated versus progressive types of CLL bearing the potential to facilitate risk-adapted treatment strategies.
Patients and methods: To evaluate the clinical value of ZAP-70 and CD38 as predictors of disease progression we assessed the expression of these markers by the flow cytometry method in 156 B-CLL patients.
Results and conclusions: Both ZAP-70 and CD38 expression were shown to predict the clinical course of the disease, while ZAP-70 expression appeared to be more predictive than CD38 expression and more relevant in defining the cases of B-CLL responsive or refractory to first line chemotherapy. A simultaneous evaluation of ZAP-70 and CD38 expression allowed distinguishing the patients groups with the most favourable prognosis as well as those with the worst. Taken together we recommend assessing both ZAP-70 and CD38 protein expression for the definition of prognostic subgroups in patients with B-CLL
Key words: B-cell chronic lymphocytic leukaemia, ZAP-70, CD38
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introduction |
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TopAbstractintroductionpatients, materials and methodsresultsdiscussionReferences |
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B-CLL is the most frequent type of adult leukaemia in western countries. It is a heterogeneous disease with a highly variable clinical course and prognosis [1
, 2]. Some patients show an indolent disease and never require treatment, while in others the clinical course is aggressive requiring intensive treatment shortly after diagnosis. The staging systems developed by Rai et al. [3] and Binet et al. [4] have been recognised as standard methods of assessing the survival and the treatment requirements in B-CLL patients. However, these systems cannot identify stable or progressive forms of the disease, especially in the early stages of B-CLL, which include most of the patients at diagnosis. Thus, there is a need to seek out other prognostic factors in the early stage of the disease to identify stable or progressive forms of CLL that might facilitate risk-adapted treatment strategies [5, 6].
The presence or absence of somatic mutations in the immunoglobulin heavy-chain variable region (IgVH) of B-CLL cells has been described as one of the most powerful prognostic factors distinguishing two disease subsets [7, 8]. The cases with mutated IgVH genes exhibit a favourable clinical course and they may never require treatment [9]; while patients with unmutated IgVH genes are characterised by a reduced survival and responsiveness to chemotherapy [10, 11]. However, IgVH sequencing is difficult to perform in a routine diagnostic laboratory. Finding a surrogate for IgVH mutational status would seem to be an important priority.
Damle et al. suggested that CD38 might identify IgVH mutation having a prognostic significance in B-CLL [11]. The prognostic value of CD38 expression was also confirmed by other authors [12]. However, subsequent studies failed to confirm CD38 as an independent prognostic factor in multivariate analysis [9, 10]. Moreover, Chevallier et al. [13] found that CD38 expression by the leukaemic cells might change during the course of the disease.
Recently the role of ZAP-70 (zeta associated protein) as a surrogate marker for IgVH mutation to help identify patients with a more aggressive clinical course was reported [14–16]. ZAP-70 is a member of the Syk-ZAP-70 protein tyrosine kinase family. It is expressed by normal T cells and natural killer cells and it plays a critical role in the development and differentiation of these cell types [15]. There is no ZAP-70 expression on normal B lymphocytes, but it was detected on B-CLL cells. It was suggested that the expression of ZAP-70 could not only predict IgVH mutational status, but it could also serve as a prognostic factor in B-CLL and its expression would be stable during the course of the disease [15].
Here, we present results from a single centre retrospective study of 156 CLL patients estimating the clinical value of ZAP-70 and CD38 expression as B-CLL prognostic factors. We analysed ZAP-70 and CD38 expression on CD19+/CD5+ leukaemic cells using flow cytometry and correlated the results with the clinical outcome and risk factors like the stage of the disease, the lymphocyte count, the lactate dehydrogenenase (LDH) and B2-microglobulin level in the series of our patients.
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patients, materials and methods |
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TopAbstractintroductionpatients, materials and methodsresultsdiscussionReferences |
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patients and samples
Between September 1996 and July 2004, peripheral blood samples were obtained from 156 newly diagnosed, previously untreated patients with B-CLL. The median age was 65 years (ranging from 34 to 84 years), including 60 female and 96 male patients. Patients were staged at the time of diagnosis according to the Rai classification. Thirty-seven patients were diagnosed at stage 0 and thirty-eight at stage 1, forty at stage 2, and twenty-one and twenty at stages 3 and 4, respectively. Diagnosis of B-CLL was made on the basis of a clinical examination as well as morphological and immunological criteria. Seventy patients whose disease was stable did not receive chemotherapy and 86 patients whose disease was progressive were treated. Response to the therapy was evaluated in 66 patients in which the following regimens were used: purine nucleoside analogues (37 patients), CHOP (cyclophosphamide, vincristin, doxorubicine, prednisone) and COP (cyclophosphamide, vincristin, prednisone) (14 patients), chlorambucil (11 patients), alemtuzumab (4 patients). All peripheral blood samples were collected in heparinized tubes and immediately processed. Mononuclear cells were isolated by density gradient centrifugation on Gradisol L (Aqua Medica, Poland). Interphase cells were removed and washed twice in phosphate-buffered saline (PBS) and then resuspended at 1 x 106 cells for future staining.
reagents
Anti-ZAP-70 antibody, clone 2F3.2 (mouse monoclonal IgG2a), was purchased from Biomol Research Laboratories. ZenonTM Alexa Fluor® 488 Mouse IgG2a Labeling Kit was obtained from Molecular Probes. Fluorescein isothiocyanate (FITC)-labelled anti-CD38 and the corresponding negative controls were obtained from PharMingen. CyChrome conjugated monoclonal antibody (MoAb) anti-CD5, CyChrome conjugated MoAb anti-CD19 and PE conjugated MoAb anti-CD19 were obtained from Caltag Laboratories.
ZAP-70 staining using ZenonTM Alexa Fluor® 488 Mouse IgG2a Labeling Kit
All samples were stained for ZAP-70 protein expression. We used the method described earlier [17]. Additionally in 20 patients we used two methods to identify ZAP-70 expression: indirect labeling ZAP-70 procedure using ZenonTM Alexa Fluor® 488 Mouse IgG2a Labeling Kit and direct labelling procedure with PE conjugated MoAb anti-ZAP-70 from Caltag Laboratories. The results obtained by these two different techniques were concordant.
100 µl of peripheral blood mononuclear cells (1 x 106 cells/ml) were stained with MoAbs against the cell-surface markers CD19 PE and CD5 CyChrome. The cells were than fixed in a 1% paraformaldehyde solution in PBS for 15 minutes at room temperature (RT) and permeabilised with 70% ethanol for at least 1 hour at –20°C. Thereafter, anti-ZAP-70 antibody labelled by the Zenon mouse IgG labelling reagents was added to the sample tubes. The samples were incubated for 30 minutes at RT, washed and immediately analysed by flow cytometry.
zenon Complex Formation
For ZAP-70 staining 1 µg cells of anti-ZAP-70 antibody per 106 cells was evaluated. Anti-ZAP-70 antibody was prepared in 20 ml of PBS. Next, the Zenon mouse IgG labelling reagent, which contained a fluorophore-labelled Fab fragment, was added to the antibody solution (5 µl of the Zenon labelling reagents were used for each 1 µg of IgG). The mixture was incubated for 5 minutes at RT. Then 5 µl of the Zenon blocking reagent was added to the reaction mixture. The solution was incubated for an additional 5 minutes and applied to the sample.
cell-surface antigens expression
Peripheral blood mononuclear cells were stained with the following MoAbs: CD38 FITC, CD19CyChrome or IgG1 isotypic control. 5 µl of each MoAb was added to the appropriate tubes and incubated for 20 min at RT. Finally, the cells were washed and analysed by flow cytometry.
flow cytometry analysis
Samples were analysed by flow cytometry using a Becton Dickinson FACSCalibur instrument equipped with a 488-nm argon laser. Five data parameters were assessed: linear forward and side scatter (FSC, SSC), FL-1(FITC), FL-2(PE) and FL-3 (CyChrome). An acquisition gate was established based on FSC and SSC that included mononuclear cells and excluded dead cells and debris. For each analysis 10 000 events were acquired and analysed using CellQuest software. Each sample was run with an appropriate isotype control and this was used to define the negatively stained cells (Figures 1 and 2).
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statistical analysis
The statistical significance of the flowcytometric results was deduced by means of the Mann-Whitney U test. Spearman rank test was used to assess the correlation between the variables. Differences were considered as statistically significant when the P value was
0.05. Survival and time to progression were estimated according to the method of Kaplan-Meier. We used Statistica 5.0 PL software for all statistical procedures. |
results |
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ZAP-70 expression in B-CLL cells
Patients were considered positive for ZAP-70 when the expression was found in 20% or more leukaemic cells. In 57 of 156 B-CLL patients (36.5%) ZAP-70 expression was found in more than 20% of leukaemic cells (32.99 ± 11.94%) and 99 patients (63.5%) tested negative for ZAP-70 expression (8.15±4.83%) (P = 0.00001).
A significant difference was noted for the two groups in terms of Rai staging (P = 0.01): of the 57 patients who expressed ZAP-70, 28 (49.1%) were in Rai stages 3–4, whereas, of the 99 patients who did not express ZAP-70, only 13 (13%) were in Rai stages 3–4. Fifteen CLL-related deaths occurred during the observation period and 12 patients of this group were ZAP-70+ (80%). In contrast only three out of 99 patients deceased in the ZAP-70– group (3%). There was a significant difference (P = 0.009) in the mean ZAP-70 expression between patients who died and patients who are still alive (37.82% versus 16.10%, respectively). ZAP-70 expression was associated with most of the known parameters for poor prognosis in B-CLL. There was a significant difference between the two groups in white blood cell (WBC) count, lymphocytosis, LDH serum activity, haemoglobin level, and platelet count (Table 1). The percentage of leukaemic cells expressing ZAP-70 correlated with the percentage of CD38+/CD19+ cells (P = 0.0001) (Figure 3). ZAP-70 expression correlated significantly with the stage of disease. In patients with stages 3–4 according Rai the percentage of leukaemic cells with the expression of ZAP-70 was higher than in patients with lower stages (P = 0.001).
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CD38 expression
Patients were considered CD38 positive when the expression was found in at least 20% of B CD19+ cells. This threshold value was previously used by Ibrahim et al. [18
] and Deaglio et al. [19]. However other authors used 30% [9, 11, 12] or even 7% [10] of CD38+ cells as the cutoff point and this issue still remains controversial. In our study, we compared two most often used values, 20% and 30%, and similarly to the comparison made previously by Domingo-Domenech et al. [20]. We did not find any significant differences in estimated parameters between these two cut-offs (data not shown). In 52 patients (33.3%) CD38 expression was found in more than 20% of leukaemic cells (40.46 ± 16.96%), and 104 patients (66.7%) tested negative for CD38 expression (7.40 ± 5.35%) (P = 0.00001). CD38 positive patients as well as ZAP-70+ patients were in the more advanced Rai stage of the disease (P = 0.013). Of the 52 CD38 positive patients, 23 (44.2%) were in stages 3–4 according to Rai. Whereas, of the 104 patients who did not show 38 expression, 18 (17.3%) were in stages 3–4 according to Rai. In addition, ten (19.2%) of the CD38+ patients died (CLL-related deaths) during the observation period, whereas among the 104 patients negative for 38 expression there were only five (4.8%) CLL-related deaths. There was no significant difference in CD38 expression between patients who died and patients who survived. As shown in Table 2, in the CD38 positive group we noted significantly higher lymphocytosis, WBC counts and LDH levels than in CD38 negative patients. In CD38 positive patients, the percentage of leukaemic cells expressing ZAP-70 protein was significantly higher than in CD38 negative ones. Likewise, the Spearman correlation between the percentage of B CD19+ cells expressing CD38 and clinical and laboratory data showed a strong and direct correlation with the percentage of leukaemic cells expressing ZAP-70 (Figure 3). In addition, the percentage of CD38+ B cells correlated slightly with the lymphocyte count (R = 0.164; P = 0.05).
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correlation between ZAP-70 and CD38 expression
For further statistical analysis, B-CLL patients were divided into four groups. In 118 patients (75.6%) there was a complete concordance of ZAP-70 and CD38 expression: 35 patients (22.4%) were positive for ZAP-70 and CD38 and 83 patients (53.2%) showed a ZAP-70–/CD38– phenotype. 22 patients (14.1%) were characterized by ZAP-70+/CD38– phenotype and 16 patients (10.3%) showed a ZAP-70–/CD38+ phenotype. Figure 4 shows a comparison of the clinical and laboratory data of the four groups. The combination of ZAP-70 and CD38 increased the prognostic power of both of the factors. The most significant differences in WBC count, lymphocytosis, PLT count and LDH serum activity were observed between patients with ZAP-70+/CD38+ and ZAP-70–/CD38– phenotype. Additionally, we found significant differences in the haemoglobin and ß2-microglobulin level between the both groups (Figure 4) and no significant differences between ZAP-70+/CD38- or ZAP-70–/CD38+ patients. Patients with ZAP-70+/CD38+ phenotype had a shorter mean event-free survival than all other patients; however, this difference was not statistically significant (Figure 4).
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ZAP-70 and CD38 expression in treated and untreated patients
Comparing the subgroups of patients with regard to their clinical characteristics, we found significant differences in time to progression as indicated by the event-free interval.
There was a significant difference in median event free survival (EFS) between ZAP-70 negative and ZAP-70 positive patients groups (10±20.8 vs. 4±15.1 months, respectively; P = 0.001) (Figure 5A).
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There was a significant difference in the median event free survival (EFS) between CD38 negative and CD38 positive patients groups (10 ± 20.9 versus 3 ± 13.4 months, respectively; P = 0.03) (Figure 5B).
In the group of patients requiring anticancer therapy, there were more patients positive for ZAP-70 and CD38 expression then in untreated patient group (Table 3). We also found a significantly higher percentage of leukaemic cells expressing ZAP-70 in patients requiring therapy during the follow-up period than in patients who did not (P = 0.032). CD38 expression was also higher in patients requiring therapy, although this difference was not statistically significant. In the group of patients requiring treatment there was a higher percentage of ZAP-70 positive than ZAP-70 negative persons, while in the group of untreated patients the number of ZAP-70 negative persons was higher. On the contrary, the percentage of CD38 negative patients was higher in both untreated as well as treated patient group (Table 3).
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Among the B-CLL patients who received anticancer treatment (Table 4) 37 patients were treated with purine nucleoside analogues (PNA) and haematological remission was achieved in 25 of them. Complete response to PNA was significantly correlated with ZAP-70 percentages (P <0.008) demonstrating that this factor might be used to predict the chemosensitivity of B-CLL patients. We found no significant differences in the CD38 percentages. Likewise, there were no significant differences in the groups treated with CHOP, COP, chlorambucil or alemtuzumab (Table 4).
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discussion |
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TopAbstractintroductionpatients, materials and methodsresultsdiscussionReferences |
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The objective of the present study was to assess the clinical significance of ZAP-70 and CD38 expression on leukaemic cells of B-CLL patients. We used flow cytometry assay to evaluate both markers expression. Flow cytometry was demonstrated earlier to be a reliable method for ZAP-70 estimation with results correlating with those obtained by the RT-PCR method [15
, 17]. In our study both ZAP-70 and CD38 expression was shown to predict the clinical course of the disease. EFS was significantly longer in ZAP-70 negative as well as in CD38 negative patient groups. However, more significant differences were found between ZAP-70 positive and ZAP-70 negative patients in B-CLL poor prognosis parameters (stage of the disease, laboratory parameters at diagnosis: WBC count, lymphocytosis, PLT count, Hgb level and LDH serum level) than between CD38 positive and negative patients (WBC count, lymphocytosis and LDH activity).
ZAP-70 was proven by many authors to be a sensitive and specific surrogate marker for IgVH mutational status, though the mechanisms accounting for the relation between both factors remain unknown [21, 23]. Moreover according to Rassenti et al. [24] the prognostic value of ZAP-70 expression is even more significant than IgVH mutational status.
The clinical significance of CD38 expression as well as its value as a surrogate marker for the IgVH gene mutational status still remains more controversial. A high CD38 expression was found to correlate with IgVH gene mutations as well as an unfavourable clinical course of B-CLL [11, 18], but this relation was not confirmed in further studies by Hamblin [22] and Krober [10]. According to Oscier et al. [9] CD38 expression cannot be used as an independent prognostic factor, but rather gives additional information in patients with an established mutational status. Domingo-Domenech et al. [20] found a link between CD38 expression and clinical and biological data, but in multivariate analysis it lost statistical significance. In multiple regression analysis by Crespo et al. [15] only ZAP-70 expression, not CD38 expression, maintained a correlation with IgVH mutational status.
Results of our study demonstrated an association between ZAP-70 expression and the treatment requirement as well as the response to anticancer therapy. In patients who required chemotherapy ZAP-70 expression was significantly higher than in still untreated patients (P = 0.032). Furthermore in all patients responding to first-line chemotherapy with purine analogues ZAP-70 expression was significantly lower than in non-responding patients (P < 0.008). There were no significant differences in CD38 expression. Among the four patients receiving MabCampath as a first line therapy complete haematological remission was achieved in only one, a ZAP-70 negative patient, while the other three patients were ZAP-70 positive and failed to respond to the treatment. In our study the expression of ZAP-70 appeared to be more relevant than CD38 expression in defining the cases of B-CLL responding and not responding to first line chemotherapy, though it was demonstrated before that CD38+ CLL patients respond poorly to chemotherapy. Del Poeta et al. [12] found a significant correlation between higher CD38 percentages and the lack of a complete response to six courses of fludarabine monophosphate as a first line approach. According to Damle et al. [11] there are significant differences, not only in survival, but also in chemotherapy requirements depending on CD38 expression. Domingo-Domenech et al. [20] found that CD38+ patients required treatment more frequently than CD38– patients. According to Wiestner et al. [16] CD38 expression distinguished patients who required treatment early versus late, albeit less well than IgVH mutation status or ZAP-70 expression. Our observations are in agreement with the earlier results of Durig et al. [14], which found that ZAP-70 positive patients required more intensive chemotherapy over longer periods of time than ZAP-70 negative patients.
For evaluation of clinical significance ZAP-70 and CD38 co-expression of B-CLL cells we analysed four groups: patients positive or negative both for ZAP-70 and CD38, and patients with discordant results: ZAP-70+/CD38– and ZAP-70–/CD38+. Among several clinical and laboratory parameters significant differences were observed only between groups that were negative or positive for both ZAP-70 and CD38 in WBC and PLT count, peripheral blood lymphocytosis and LDH activity (Figure 4). This observation suggests taking into account both parameters when undertaking therapeutic decisions in CLL patients. There are still controversies in this issue. Orchard et al. [21] noted that CD38 had weak prognostic value in univariate analysis but did not improve the predictive power of either ZAP-70 or IgVH mutational status in multivariate analysis. However, according to Durig et al. the combination of ZAP-70 and CD38 may increase the prognostic power of either of the two factors [14], and Schroers et al. showed recently in a large series of patients, that combined analysis of ZAP-70 and CD38 expression provided complementary prognostic information [25].
In conclusion, both ZAP-70 and CD38 expression were shown to predict the clinical course of the disease. ZAP-70 expression appeared however to be more predictive than CD38 expression and more relevant in defining the cases of B-CLL responding and non-responding to first line chemotherapy. Our results suggest that a simultaneous estimation of ZAP-70 and CD38 expression could distinguish the patient groups with the most favourable, as well as the least prognosis. Both markers are evaluated by flow cytometry, which is a routine technique in most laboratories. Performing this combined analysis could serve for either precise definition of prognostic subgroups or might be an option to confirm the prognosis if the value of one predictive factor is borderline.
Received for publication July 28, 2005. Revision received November 15, 2005. Accepted for publication November 29, 2005.
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References |
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1. Hamblin T. Chronic lymphocytic leukaemia: one disease or two? Ann Hematol 2002; 81: 299–303.[CrossRef][Medline]
2. Kipps TJ. Chronic lymphocytic leukemia. Curr Opin Hematol 2000; 7: 223–234.[CrossRef][Medline]
3. Rai K, Sawitsky A, Cronckite EP et al. Clinical staging of chronic lymphocytic leukemia. Blood 1975; 46: 219–234.
4. Binet JL, Auquier A, Dighiero G et al. A new prognostic classification of chronic lymphocytic leukemia derived from a multivariate survival analysis. Cancer 1981; 48: 198–206.[CrossRef][Web of Science][Medline]
5. Byrd JC, Waselenko JK, Keating M et al. Novel therapies for chronic lymphocytic leukemia in the 21st century. Semin Oncol 2000; 27: 587–597.[Medline]
6. Zwiebel JA, Cheson BD. Chronic lymphocytic leukemia: staging and prognostic factors. Semin Oncol 1998; 25: 42–59.[Web of Science][Medline]
7. Hamblin TJ, Davis Z, Gardiner A et al. Unmutated Ig V(H) genes are associated with a more aggressive form of chronic lymphocytic leukemia. Blood 1999; 94: 1848–1854.
8. Oscier DG, Thompsett A, Zhu D, Stevenson FK. Differential rates of somatic hypermutation in V(H) genes among subsets of chronic lymphocytic leukemia defined by chromosomal abnormalities. Blood 1997; 89: 4153–60.
9. Oscier DG, Gardiner AC, Mould SJ et al. Multivariate analysis of prognostic factors in CLL: clinical stage, IGVH gene mutational status, and loss or mutation of p53 gene are independent prognostic factors. Blood 2002; 100: 1177–1184.
10. Kröber A, Seiler T, Benner A et al. VH mutation status, CD38 expression level, genomic aberrations, and survival in chronic lymphocytic leukemia. Blood 2002; 100: 1410–1416.
11. Damle RN, Wasil T, Fais F et al. Ig V gene mutation status and CD 38 expression as a novel prognostic indicators in chronic lymphocytic leukemia. Blood 1999; 94: 1840–1847.
12. Del Poeta G, Maurillo L, Venditti A et al. Clinical significance of CD38 expression in chronic lymphocytic leukemia. Blood 2001; 98: 2633–2639.
13. Chevallier P, Penther D, Avet-Loiseau H, et al. CD38 expression and secondary 17p deletion are important prognostic factors in chronic lymphocytic leukaemia. Br J Haematol 2002; 116: 142–150.[CrossRef][Medline]
14. Durig J, Nuckel H, Cremer M et al. ZAP-70 expression is a prognostic factor in chronic lymphocytic leukemia. Leukemia 2003; 17: 2426–2434.[CrossRef][Web of Science][Medline]
15. Crespo M, Bosch F, Villamor N et al. ZAP-70 expression as a surrogate for immunoglobulin-variable-region mutations in chronic lymphocytic leukemia. N Engl J Med 2003; 348: 1764–1775.
16. Wiestner A, Rosenwald A, Barry TS et al. ZAP-70 expression identifies a chronic lymphocytic leukemia subtype with unmutated immunoglobulin genes, inferior clinical outcome, and distinct gene expression profile. Blood 2003; 101: 4944–4951.
17. Bojarska-Junak A, Roliski J, Kawiak J. Modification of immunocytochemical ZAP-70 assay for potential clinical application in B-cell chronic lymphocytic leukemia. Folia Histochemica et Cytobiologica 2005; 43: 19–23.[Medline]
18. Ibrahim S, Keating M, Do KA et al. CD38 expression as an important prognostic factor in B-cell chronic lymphocytic leukemia. Blood 2001; 98: 181–186.
19. Deaglio S, Capobianco A, Bergui L et al. CD38 is a signaling molecule in B-cell chronic lymphocytic leukemia cells. Blood 2003; 102: 2146–2155.
20. Domingo-Domenech E, Domingo-Claros A, Gonzalez-Barca E et al. CD38 expression in B-cell chronic lymphocytic leukemia: association with clinical presentation and outcome in 155 patients. Haematologica 2002; 87: 1021–1027.[Web of Science][Medline]
21. Orchard JA, Ibbotson RE, Davis Z et al. ZAP-70 expression and prognosis in chronic lymphocytic leukaemia. Lancet 2004; 363: 105–111.[CrossRef][Web of Science][Medline]
22. Hamblin TJ, Orchard JA, Ibbotson RE et al. CD38 expression and immunoglobulin variable region mutations are independent prognostic variables in chronic lymphocytic leukemia, but CD38 expression may vary during the course of the disease. Blood 2002; 99: 1023–1029.
23. Kim SZ, Chow KU, Kukoc-Zivojnov N et al. Expression of ZAP-70 correlates with disease stage in chronic lymphocytic leukaemia and is associated with, but not generally restricted to, non-mutated IgVH status. Leuk Lymph 2004; 45: 2037–2045.[CrossRef][Medline]
24. Rassenti L, Huynh L, Toy TL et al. ZAP-70 compared with immunoglobulin heavy-chain gene mutation status as a predictor of disease progression in chronic lymphocytic leukaemia. N Engl J Med 2005; 351: 893–901.
25. Schroers R, Griesinger F, Trumper L et al. Combined analysis of ZAP-70 and CD38 expression as a predictor of disease progression in B-cell lymphocytic leukaemia. Leukemia 2005; 19: 750–758.[CrossRef][Web of Science][Medline]
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