FCRL2 mRNA expression is inversely associated with clinical progression in chronic lymphocytic leukemia

Abstract

Fc receptor-like 2 (FCRL2) is highly expressed on B-cell chronic lymphocytic leukemia (B-CLL) cells and could possibly influence disease pathogenesis. Therefore, we investigated FCRL2 mRNA expression in a large cohort with 152 CLL patients in order to assess its role in risk prediction in B-CLL. FCRL2 mRNA expression was found to be expressed at considerably higher levels in peripheral blood mononuclear cells (PBMC) of B-CLL patients compared to controls (range 1.35- to 210-fold upregulation; P < 0.0001) and cells of other hematological diseases. Patients with high FCRL2 expression (according to ROC-analysis) had a significantly longer treatment-free survival (TFS) and overall survival (OS) than patients with low FCRL2 expression (median TFS: 119 vs. 34 months, P < 0.0001; median OS: 321 months vs. not reached, P = 0.009). Univariate comparisons found that FCRL2 expression was weakly associated with IGHV mutation status (P = 0.05), CD38 status (P < 0.0001) and ZAP-70 status (P < 0.0001). Furthermore, we show that the combination of FCRL2 with ZAP70-, CD38- or IGHV-status could further significantly refine the prognostic information provided by either of the factors alone in TFS and OS. In multivariate analysis low FCRL2 expression was a significant independent prognostic factor (HR 2.4; P = 0.005). Here we demonstrate that the level of FCRL2 expression is correlated with prognosis in B-CLL.