Chronic Lymphocytic Leukemia Prognostic Index： A New Inteorated Scorino System to Predict the Time to First Treatment in Chinese Patients with Chronic Lymphocytic Leukemia

Background： The established clinical staging systems （Rai/Binet） of chronic lymphocytic leukemia （CLL） cannot accurately predict the appropriate treatment of patients in the earlier stages. In the past two decades, several prognostic factors have been identified to predict the outcome of patients with CLL, but only a few studies investigated more markers together, To predict the time to first treatment （TTFT） in patients of early stages, we evaluated the prognostic role of conventional markers as well as cytogenetic abnormalities and combined them together in a new prognostic scoring system, the CLL prognostic index （CLL-PI）. Methods： Taking advantage of a population of 406 untreated Chinese patients with CLL at early and advanced stage of disease, we identified the strongest prognostic markers of TTFT and, subsequently, in a cohort of 173 patients who had complete data for all 3 variables, we integrated the data of traditional staging system, cytogenetic aberrations, and mutational status of immunoglobulin heavy chain variable region （1GI：tV） in CLL-PI. The median follow-up time was 45 months and the end point was TTFT. Results： The median TTFT was 38 months and the 5-year overall survival was 80%. According to univariate analysis, patients of advanced Rai stages （P 〈 0.001） or with 11q- （P = 0.002）, 17p- （P 〈 0.001）, unmutated IGHV （P 〈 0.001）, negative 13q- （P = 0.007） and elevated lactate dehydrogenase levels （P = 0.001 ） tended to have a significantly shorter TTFT. And subsequently, based on multivariate Cox regression analysis, three independent factors for TTFT were identified： advanced clinical stage （P = 0.002）, 17p- （P = 0.050） and unmutated 1GHV （P = 0.049）. Applying weighted grading of these independent factors, a CLL-PI was constructed based on regression parameters, which could categorize tbur different risk groups （low risk [score 0], intermediate low [score 1], intermediate high [score 2] and high risk [score 3-6]） with significantly different TTFT （median TTFT of not reached （NR）, 65.0 months, 36.0 months and 19.0 months, respectively, P 〈 0.001 ）. Conclusions： This study developed a weighted, integrated CLL-PI prognostic system of CLL patients which combines the critical genetic prognostic markers with traditional clinical stage. This novel modified PI system could be used to discriminate among groups and may help predict the TTFT and prognosis of patients with CLL.

TOSO interacts with SYK and enhances BCR pathway activation in chronic lymphocytic leukemia

Background:TOSO,also named Fas inhibitory molecule 3(FAIM3),has recently been identified as an immunoglobulin M(IgM)Fc receptor(FcμR).Previous studies have shown that TOSO is specifically over-expressed in chronic lymphocytic leukemia(CLL).However,the functions of TOSO in CLL remain unknown.The B-cell receptor(BCR)signaling pathway has been reported to be constitutively activated in CLL.Here,we aimed to investigate the functions of TOSO in the BCR signaling pathway and the pathogenesis of CLL.Methods:We over-expressed TOSO in B-cell lymphoma cell lines(Granta-519 and Z138)by lentiviral transduction and knocked down TOSO by siRNA in primary CLL cells.The over-expression and knockdown of TOSO were confirmed at the RNA level by polymerase chain reaction and protein level by Western blotting.Co-immunoprecipitation with TOSO antibody followed by liquid chromatography coupled with tandem mass spectrometry(IP/LCMS)was used to identify TOSO interacting proteins.Western blotting was performed to detect the activation status of BCR signaling pathways as well as B-cell lymphoma 2(BCL-2).Flow cytometry was used to examine the apoptosis of TOSO-over-expressing B lymphoma cell lines and TOSO-down-regulated CLL cells via the staining of Annexin V and 7-AAD.One-way analyses of variance were used for intergroup comparisons,while independent samples t tests were used for two-sample comparisons.Results:From IP/LCMS,we identified spleen tyrosine kinase(SYK)as a crucial candidate of TOSO-interacting protein and confirmed it by co-immunoprecipitation.After stimulation with anti-IgM,TOSO over-expression increased the phosphorylation of SYK,and subsequently activated the BCR signaling pathway,which could be reversed by a SYK inhibitor.TOSO knockdown in primary CLL cells resulted in reduced SYK phosphorylation as well as attenuated BCR signaling pathway.The apoptosis rates of the Granta-519 and Z138 cells expressing TOSO were(8.46±2.90)%and(4.20±1.21)%,respectively,significantly lower than the rates of the control groups,which were(25.20±4.60)%and(19.72±1.10)%,respectively(P<0.05 for both).The apoptosis rate was reduced after knocking down TOSO in the primary CLL cells.In addition,we also found that TOSO down-regulation in primary cells from CLL patients led to decreased expression of BCL-2 as well as lower apoptosis,and vice versa in the cell line.Conclusions:TOSO might be involved in the pathogenesis of CLL by interacting with SYK,enhancing the BCR signaling pathway,and inducing apoptosis resistance.