Deletion of 13q14 Is Independent of CD38 Expression in Chronic Lymphocytic Leukemia (CLL).

Cytogenetic abnormalities detected by fluorescent in situ hybridization (FISH) can predict differences in survival in patients with CLL. Patients (pts) with the 13q14 deletion experience a longer median survival that those with the 17p13.1 deletion. Overexpression of ZAP-70 and CD38 correlate with a poor prognosis. Data on 44 pts currently enrolled on a prospective CLL prognostic study were analyzed for cytogenetic abnormalities by FISH and CD38 by flow. Pt age ranged from 25 to 85 (median 59). 25/44 patients (57%) were followed without any therapy. Zap-70 expression was measured by immunohistochemistry using a monoclonal antibody to ZAP-70 (clone 2F3.2).

Results: 22/44 (50%) pts were found to have abnormal cytogenetics. Of the 22 abnormalities, 17 had a 13q14 deletion (including one with an additional 11q22.31 deletion, and two with nullisomy 13q), five patients had trisomy 12, one patient a 17 p13.1 deletion. 8/44 patients overexpressed CD38. Of the pts with an isolated 13q deletion, 12/16 (75%) were CD38 negative and 10/17 (59%) were followed without any therapy, compared to 20/27 (74%) and 14/27 (52%) in those with other cytogenetic features respectively. Of those with other abnormal FISH findings, 4/5 pts (90%) with trisomy 12 were CD38 negative, a patient with 17p13.1 deletion and another patient with both 13q14 and 11q deletion were also CD38 positive. Of the patients with normal FISH results 19/21 (90%) were CD38 negative. ZAP-70 overexpression was noted in 22/26 pts with available data including 8/10 (80%) patients with and 13/26 (50%) patients without the 13q del.

Conclusion: The presence of the 13q14 deletion appeared to be independent of CD38 expression. Further studies to determine the association of 13q14 deletion with ZAP-70 expression are warranted, as is the correlation with clinical data.