Ding, Wei

Abstract Background: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) is the most common adult leukemia in the United States. Prior studies in Olmsted County, Minnesota, showed a CLL age and sex adjusted incidence rate of 6.6 per 100,000 during 1985-89. Subsequently, the definition of CLL is now based on the 2008 International Workshop on CLL (IWCLL) Guidelines. Individuals having a CLL immunophenotype by flow cytometry are classified as CLL if the absolute B-cell count (ABC) is >5 x 109/L or classified as monoclonal B-cell lymphocytosis (MBL) if ABC is <5 x 109/L. To assess the impact of these changes on the incidence of CLL and clinically discovered MBL, we conducted an incidence study in Olmsted County for the years 2000-2010. Methods Using diagnostic indexes available through the Rochester Epidemiology Project and the Mayo CLL database, we identified all CLL and clinically identified MBL cases from 2000-2010. Incidence rates and demographics were compared between the older National Cancer Institute-Working Groups 1996 guidelines (NCI-WG 96) defined as absolute lymphocyte count (ALC)> 5 x 109/L and the IWCLL 2008 guidelines defined as ABC > 5 x 109/L. Incidence rates were age and sex adjusted using the 2010 US white population. Time to treatment (TTT) survival analyses was from time of diagnosis to date of first treatment or last follow-up and Cox regression analysis was used. Results Using the NCI-WG 96 classification, there were 8 MBL cases and 115 CLLs in whom 61% were Rai stage 0, 34% were Rai stage 1-2, and 5% were Rai stage 3-4. Using the IWCLL 2008 classification, there were 44 MBL cases and 79 CLLs in whom 43% Rai stage 0, 49% were Rai stage 1-2 and 8% Rai stage 3-4. Median ALC at diagnosis was 8.1 x 109/L for CLL and 5.9 x 109/L for MBL. Median ABC count at diagnosis was 7.1 x 109/L for CLL and 2.8 x 109/L for MBL. The age and sex adjusted incidence rate (per 100,000) for CLL for 2000-2010 was 10.0 using NCI-WG 96 and 6.8 using IWCLL 2008. Rates for MBL were 0.66 using NCI-WG 96 and 3.5 using IWCLL 2008. The median TTT for CLL was 9.2 years using NCI-WG 96 and 6.5 years by IWCLL 2008. Discussion This study demonstrates that reclassification of CLL using the IWCLL 2008 guidelines decreases CLL incidence relative to the NCI-WG 96 criteria. For the first time, this population based study also establishes an incidence rate for clinically identified MBL. Approximately 50% of previously labeled Rai 0 CLL are now reclassified as MBL. Re-classification increases the percent of Rai stage 1-2 and decreases the percent of Rai 0 cases at diagnosis. Reclassification also substantially shortens the median TTT for newly diagnosed CLL cases classified by the 2008 criteria relative to the NCI-WG 96 criteria. In summary, the IWCLL 2008 reclassification has significant implications for incidence studies, staging, and prognosis of CLL and MBL. Citation Format: Aaron D. Norman, Timothy G. Call, Curtis A. Hanson, Neil E. Kay, Clive S. Zent, Wei Ding, James R. Cerhan, Sara J. Achenbach, Kari G. Rabe, Celine M. Vachon, Emily J. Hallberg, Tait D. Shanafelt, Susan L. Slager. Incidence of chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis in Olmsted county, 2000-2010: impact of the 2008 International Workshop on CLL Guidelines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2287. doi:10.1158/1538-7445.AM2013-2287

BACKGROUNDThe 1996 National Cancer Institute Working Group (NCI‐WG 96) guidelines classified disease in individuals who had a B‐cell clone with chronic lymphocytic leukemia (CLL) immunophenotype as CLL if their absolute lymphocyte count was ≥5 × 109/L. The 2008 International Workshop on CLL guidelines (IWCLL 2008) classified disease as CLL if the absolute B‐cell count was ≥5 × 109/L or as monoclonal B‐cell lymphocytosis (MBL) if the absolute B‐cell count was <5 × 109/L. The objective of the current study of Olmsted County, Minnesota, was to assess the effects of these changes on incidence rates and presentation from 2000 to 2010.METHODSUsing diagnostic indices available through the Rochester Epidemiology Project and the Mayo CLL database, the authors identified all patients with newly diagnosed CLL and high‐count MBL from 2000 to 2010. Age‐specific and sex‐specific incidence rates were determined.RESULTSAccording to NCI‐WG 96 criteria, there were 115 patients with CLL and 8 patients with MBL during the period studied. Using the IWCLL 2008 classification, there were 79 patients with CLL and 40 patients with MBL. Rai stage distribution (low risk, intermediate risk, and high risk) using NCI‐WG 96 criteria was 60.9%, 33.9%, and 5.2%, respectively, compared with 43%, 49.4%, and 7.6%, respectively, using IWCLL 2008 criteria. The age‐adjusted and sex‐adjusted incidence rates (per 100,000) for CLL and MBL were 10.0 and 0.66, respectively, using NCI‐WG 96 criteria versus 6.8 and 3.5, respectively, using IWCLL 2008 criteria. The median time to treatment according to NCI‐WG 96 criteria was 9.2 years versus 6.5 years with IWCLL 2008 criteria.CONCLUSIONSUse of the IWCLL 2008 guidelines reduced the incidence of CLL, altered the distribution of initial Rai stage at diagnosis, and shortened the median time to treatment. Cancer 2014;120:2000–2005. © 2014 American Cancer Society.

SummaryNearly all information about patients with chronic lymphocytic leukaemia (CLL) who develop diffuse large B‐cell lymphoma [Richter syndrome (RS)] is derived from retrospective case series or patients treated on clinical trials. We used the Mayo Clinic CLL Database to identify patients with newly diagnosed CLL between January 2000 and July 2011. Individuals who developed biopsy‐proven RS during follow‐up were identified. After a median follow‐up of 4 years, 37/1641 (2·3%) CLL patients developed RS. The rate of RS was approximately 0·5%/year. Risk of RS was associated with advanced Rai stage at diagnosis (P < 0·001), high‐risk genetic abnormalitites on fluorescence in situ hybridization (P < 0·0001), unmutated IGHV (P = 0·003), and expression of ZAP70 (P = 0·02) and CD38 (P = 0·001). The rate of RS doubled in patients after treatment for CLL (1%/year). Stereotyped B‐cell receptors (odds‐ratio = 4·2; P = 0·01) but not IGHV4‐39 family usage was associated with increased risk of RS. Treatment with combination of purine analogues and alkylating agents increased the risk of RS three‐fold (odds‐ratio = 3·26, P = 0·0003). Median survival after RS diagnosis was 2·1 years. The RS prognosis score stratified patients into three risk groups with median survivals of 0·5 years, 2·1 years and not reached. Both underlying characteristics of the CLL clone and subsequent CLL therapy influence the risk of RS. Survival after RS remains poor and new therapies are needed.

AbstractA 55-year-old man presented with fever, night sweats, and weight loss of about 20 lbs. in the prior 6 months. Physical examination revealed multiple cervical, axillary, and inguinal lymphadenopathy. The spleen was enlarged. A complete blood count revealed leukocytosis with absolute lymphocytosis: 30,000/μL. Peripheral blood-flow cytometric analysis showed a clonal lymphocyte population with immunophenotypes positive for CD5, CD20(dim), and monotypic kappa light chain. Fluorescence in situ hybridization (FISH) analysis revealed del(11q22.3), but negative for t(11:14). What should be used to treat his chronic lymphocytic leukemia (CLL) disease?

Abstract Malignant cells are capable of influencing the microenvironment in a manner that facilitates tumor cell survival. Bidirectional crosstalk between chronic lymphocytic leukemic (CLL) cells and marrow-derived mesenchymal stromal cells (MSCs) activates both cell types. In this study, we observed that the conditioned medium (CM) obtained from CLL cells was able to induce Akt activation in MSC. Subsequent studies investigated the mechanism of MSC activation mediated by CLL-CM. Platelet-derived growth factor receptors (PDGFRs) were selectively activated in MSCs by CLL-CM and found to be critical receptors for CLL-CM–driven MSC proliferation and MSC Akt activation. The known ligands of PDGFR, platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), were detected in CLL-CM, but PDGF was the predominant ligand involved in the CM-mediated PDGFR activation. Both PDGF and VEGF were found to be elevated in the plasma of CLL patients with a positive association for high-risk factors and more advanced stage. Finally, we demonstrated that PDGF induced MSC VEGF production through a phosphatidylinositol 3-kinase (PI3K)–dependent mechanism. These results show that PDGF-PDGFR signaling influences at least the MSC in the microenvironment of CLL and may play a role in the induction of an angiogenic switch known to be permissive for disease progression.

Abstract Marrow stromal cells (MSCs) provide important survival and drug resistance signals to chronic lymphocytic leukemia (CLL) cells, but current models to analyze CLL–MSC interactions are heterogeneous. Therefore, we tested different human and murine MSC lines and primary human MSCs for their ability to protect CLL cells from spontaneous and drug-induced apoptosis. Our results show that both human and murine MSCs are equally effective in protecting CLL cells from fludarabine-induced apoptosis. This protective effect was sustained over a wide range of CLL–MSC ratios (5:1 to 100:1), and the levels of protection were reproducible in 4 different laboratories. Human and murine MSCs also protected CLL cells from dexamethasone- and cyclophosphamide-induced apoptosis. This protection required cell–cell contact and was virtually absent when CLL cells were separated from the MSCs by micropore filters. Furthermore, MSCs maintained Mcl-1 and protected CLL cells from spontaneous and fludarabine-induced Mcl-1 and PARP cleavage. Collectively, these studies define common denominators for CLL cocultures with MSCs. They also provide a reliable, validated tool for future investigations into the mechanism of MSC–CLL cross talk and for drug testing in a more relevant fashion than the commonly used suspension cultures.