Lipoprotein Lipase mRNA Expression in Whole Blood Is a Prognostic Marker in B Cell Chronic Lymphocytic Leukemia Femke Van Bockstaele, 1† Valerie Pede, 1† Ann Janssens, 2 Filip Callewaert, 1 Fritz Offner, 2 Bruno Verhasselt, 1 and Jan Philippe ´ 1* Background: Chronic lymphocytic leukemia (CLL) is characterized by high individual variability in clinical course and the need for therapy. Differentiation of prognostic subgroups is based primarily on the muta- tion status of the genes for the variable region of the immunoglobulin heavy chain (IGHV). The time- and labor-intensive nature of this analysis necessitates the use of easily applicable surrogate markers. Methods: We developed a quantitative PCR (qPCR) method for determining lipoprotein lipase (LPL) mRNA expression and analyzed samples of lysed whole blood and CD19-selected cells from 50 CLL patients. Associa- tions of LPL and ZAP70 [-chain (TCR) associated pro- tein kinase 70 kDa] expression with IGHV mutation status, overall survival (OS), and treatment-free survival (TFS) were investigated. Results: Lysed samples of whole blood and CD19- selected cells were similar with respect to LPL expres- sion (R  0.88; P <0.0001). LPL expression was signifi- cantly associated with IGHV mutation status [ 2 (1)  15.3; P <0.0001] and showed an 89.3% specificity, a 68.2% sensitivity, an 83.3% positive predictive value, and a 78.1% negative predictive value for IGHV muta- tion status. LPL expression was significantly associated with both OS and TFS in log-rank tests (both P values  0.002). LPL-positive patients had a significantly shorter median TFS time (23 months) than LPL-negative pa- tients (88 months) (P  0.002). Conclusions: LPL mRNA expression is a valuable prog- nostic marker in CLL. The method does not require cell purification, and its applicability with archived samples facilitates its use in the clinical routine and other studies. © 2007 American Association for Clinical Chemistry Chronic lymphocytic leukemia (CLL) 3 is heterogeneous with a continuous spectrum of disease (1). At one extreme are patients who have an almost normal life expectancy with no need for treatment; at the other are patients who die of drug-resistant disease as early as 2 years after initial diagnosis (2). The appearance of new therapies has shifted the therapeutic goal from control of the leuko- cytosis to the achievement of a molecular remission, especially in younger patients, for whom the CLL diag- nosis has a significant impact on life expectancy. There- fore, reliable prognostic factors are of utmost importance in the design of randomized clinical trials for determining if early treatment is meaningful for all younger patients or at least for a high-risk subgroup of such patients. The current clinical consensus recommends against relying exclusively on clinical staging systems such as the Rai (3) or Binet (4) score for prognostic assessment of CLL patients. An assessment of biological and genetic markers at diagnosis has provided more accurate predictions of disease outcome, and it is important, therefore, that such markers be evaluated in clinical trials. Markers recently demonstrated to be of value are the mutation status of the genes of the variable region of the immunoglobulin heavy chain (IGHV) and the expression of CD38 and ZAP70 [-chain (TCR) associated protein kinase 70kDa]. The 1 Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium. 2 Department of Internal Medicine, Ghent University, Ghent, Belgium. † These authors contributed equally to this study. * Address correspondence to this author at: 2P8, Ghent University Hospi- tal, De Pintelaan 185, B-9000 Ghent, Belgium. Fax: 32-9-2404985; e-mail Jan.Philippe@UGent.be. Received July 14, 2006; accepted November 7, 2006. Previously published online at DOI: 10.1373/clinchem.2006.076331 3 Nonstandard abbreviations: CLL, chronic lymphocytic leukemia; IGHV, variable region of the immunoglobulin heavy chain; qPCR, quantitative PCR; TFS, treatment-free survival; Ct, threshold cycle; OS, overall survival; LDT, lymphocyte doubling time. Clinical Chemistry 53:2 204 –212 (2007) Molecular Diagnostics and Genetics 204