Citations

Abstract Abstract 429 BACKGROUND: While standard clinical prognostic factors such as those included in the International Prognostic Score (IPS) predict outcome in cHL patients, predicting the outcome of patients might be further refined using biological factors. We therefore tested whether pretreatment serum cytokines, that measure the biological activity of the tumor as well as the host response, could provide additional prognostic information in cHL patients. METHODS: Newly diagnosed cHL patients were prospectively enrolled in the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER). Serum cytokines were measured from pretreatment blood draws using a multiplex ELISA (Invitrogen, Camarillo, CA). Thirty cytokines, including pro-inflammatory, Th1 and Th2 associated cytokines, were analyzed using the Luminex-100 system Version 1.7 (Luminex, Austin, TX). Data analysis was performed using the MasterPlex QT 1.0 system (MiraiBio, Alameda, CA). The assay was also performed on research serum draws from 50 non-lymphoma epidemiology controls enrolled on a corresponding lymphoma etiology case-control study. The upper limit of normal for each cytokine was defined as the 95th percentile from the control distribution. Clinical data were abstracted using a standard protocol and all patients were followed systematically for event-free (progression, retreatment, or death due to any cause) and overall survival (EFS and OS, respectively). Cox proportional hazards models were used to evaluate the association between cytokines and outcome. RESULTS: 140 HL patients with cHL diagnosed between September 2002 and February 2008 with available pretreatment serum were included. The median age was 40 years (range 18–89) and 53% were male. Seventy-seven patients (55%) had limited stage disease and 63 (45%) had advanced disease. One hundred and twenty one patients (86%) were treated with ABVD chemotherapy, while the remainder received the Stanford V regimen (9%), BEACOPP (4%) or MOPP chemotherapy (2%). At a median follow-up of 47 months (range 0–87), 25 patients (18%) had an event and 16 patients had died (11%). The serum levels of 12 cytokines (EGF, FGFb, GCSF, HGF, IL-6, IL-8, IL-12, IL-2R, IP-10, MIG, TNFa and VEGF) were significantly higher in cHL patients than controls. When correlated with clinical factors, IL-2R, IP-10, MIG, IL-6 and HGF were associated with an increased sedimentation rate, B-symptoms, advanced stage and splenic involvement. Elevated IL-8 levels were associated with bulky disease. Elevated levels of HGF, IL-6, IL-8, IL-2R, IP-10 and MIG were all associated with a poorer EFS, however only IL-2R (p=0.002) and IL-6 (p<0.001) were independently prognostic for both EFS and OS. Furthermore, using IL-6 and IL-2R in a 2-cytokine model (see Figure), patients with elevation of both cytokines had a dramatically greater likelihood of early relapse and death than those with normal levels or elevations of only one of the cytokines (1-year EFS 40% compared to 97% and 93% respectively, p<0.0001; 2-year OS 49% compared to 98% and 95%, p<0.0001). While elevated IL-6 and IL-2R levels correlated with the IPS (p=0.002), this 2-cytokine model remained independently predictive of prognosis. In fact, when only good risk patients (IPS 0–3) were considered, the 2-cytokine model remained predictive of patients at risk for early relapse (1-year EFS 54% versus 95% and 97%, p<0.0001). CONCLUSION: Elevated pretreatment serum cytokines are associated with an increased likelihood of disease relapse and an inferior survival in patients with cHL. The pretreatment cytokine profile, particularly serum levels of IL-6 and IL-2R, may identify cHL patients at high risk for early disease relapse who may benefit from novel therapeutic approaches. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3927 Poster Board III-863 In previous studies we characterized the t(X;14)(p11.4;q32) translocation in a patient with MALT lymphoma and found that GPR34, an orphan G-protein coupled receptor (GPCR), was highly expressed due to its juxtaposition to the IGHSA2 switch region. As part of a larger MALT gene expression-profiling project, we have now acquired gene expression analysis on the patient carrying the t(X;14)(p11;q32) translocation and have confirmed overexpression of GPR34. We then measured GPR34 mRNA expression in a panel of MALT lymphomas (n=17) and found that GPR34 was expressed at levels higher than that seen in normal B cells (mean, 11.3 fold; median, 5.5; range, 1.4-64 fold). When analyzed separately, 70% (12/17) had an expression level greater than 3-fold over normal B cells. Of note, in a gastric MALT lymphoma specimen, we found a 64 fold increase in GPR34 mRNA expression. FISH studies performed on this specimen showed an extra intact GPR34 signal but no translocation involving IGH or GPR34, suggesting that other mechanisms, including gene dosage effect, can upregulate GPR34. Elevated expression of GPR34 mRNA was also detected in other histologic types of NHL, but not to the extent seen in MALT lymphoma. Taken together, these data suggest that GPR34 is commonly overexpressed in MALT lymphoma and that deregulation of GPR34 expression can occur independent of a t(X;14)(p11.4;q32) translocation. The receptor encoded by GPR34 is most similar to the PY2 receptor subfamily of GPCR and GPR34 mRNA transcripts are abundant in mast cells while lower levels were detected in other immune cells including B cells. Signals from GPR34 have been briefly described and the results to date suggest that overexpression of GPR34 results in an accumulation of inositol phosphates. To further characterize the impact of GPR34 overexpression on cell signaling, HeLa cells were transduced with a retroviral expression plasmid (pBMN-GFP) that expresses GPR34 and GFP. GFP expressing cells were isolated and overexpression of GPR34 mRNA was confirmed by PCR and GPR34 protein expression was detected by flow cytometry. When normalized to the isotype control, pBMN-GPR34 cells expressed 17-fold more GPR34 on their cell surface compared to the pBMN-vector control cells. To determine which signaling pathways were affected by GPR34 overexpression, pBMN-GPR34 or pBMN-vector control cells were transfected with an AP-1, CRE, NF-κB, E2F, SRE, NFAT, or ISRE- luciferase reporter plasmid. Upon normalization with renilla, pBMN-GPR34 expressing cells had increased luciferase activity (n=3) driven by AP-1 (5.35-fold), CRE (4.7), NF-κB (2.8-fold), and E2F (2.13) when compared to pBMN-vector control cells. ISRE, NFAT, and SRE mediated luciferase expression was similar in the GPR34 and control cells. AP-1 and CRE have been implicated in a large variety of cellular processes, including transformation, and both AP-1 and CRE activity is induced upon activation of MAP kinases. To determine if MAPK activity was also upregulated in GPR34 expressing cells, we analyzed the phosphorylation status of Erk1/2 in pBMN-GPR34 cells by western blot and found that Erk1/2 was constitutively phosphorylated in GRP34 expressing cells (1.8 fold increase) compared to vector control cells. Increased phosphorylation of PKC-α/β was also detected in pBMN-GPR34 cells (3.5 fold increase compared to control cells). To determine the biologic impact of GRP34 overexpression on cell growth, the proliferation rates of pBMN-control and pBMN-GPR34 cells were compared and it was found that proliferation of GPR34 expressing cells was 2.2 times higher than that seen in control cells. Because the MAPK kinase pathway was found to be active in the pBMN-GPR34 cells, we tested the effect of the MEK inhibitor PD98059 on proliferation and saw a dose dependent decrease in proliferation of GPR34 expressing cells. These results suggest that GPR34-mediated proliferation is Erk-dependent. In summary, these data suggest that deregulation of GPR34 is commonly found in MALT lymphoma and that overexpression of GPR34 results in activation of Erk1/2, phosphorylation of PKC, and results is AP-1 and CRE mediated transcription. Additionally, our data suggest that overexpression of GPR34 results in increased cell growth that is MAPK-dependent. Taken together, this studies indicate that overexpression of a GPCR, GPR34, may be a novel mechanism by which MALT, lymphoma, and potentially other subtypes of NHL, develop. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Patients with newly diagnosed, advanced-stage, follicular B-cell non-Hodgkin’s lymphomas (NHL) commonly receive rituximab as initial therapy. While antibody dependent cytotoxicity (ADCC) is felt to be the predominant mechanism of action for rituximab, the immunologic effects of rituximab are largely unknown. We have previously shown that genetic polymorphisms in IL-8, IL-2, IL-12 and IL-1 receptor antagonist (IL-1RN) have prognostic significance in follicular lymphoma. The goal of this study was to measure changes in the abovementioned and other serum cytokine levels in patients receiving single agent rituximab as initial therapy for follicular NHL and to identify cytokines that are associated with an increased risk of disease relapse. Methods: Patients with untreated follicular grade 1 NHL, and measurable stage III/IV disease were treated with rituximab 375 mg/m2 intravenous weekly for 4 doses and were then followed for response and time to progression (TTP); no maintenance therapy was provided. Thirty-seven patients were enrolled in this clinical trial between July 1999 and May 2001. As previously reported, the overall response rate in the 36 eligible patients was 72%, with 36% complete remissions. Now, with a median follow up of 5.1 years, the median TTP is 2.2 years (95% CI, 1.2–3.3 years) and the 5-year overall survival is 77% (95% CI: 64–92%). We measured the serum levels of a variety of inflammatory cytokines by ELISA at baseline and 1 month after completing treatment. Serum specimens were available in 30 patients. Thirty two cytokines or receptors including IL-1β, IL-1RN, IL-2, IL-2R, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 p40/p70, IL-13, IL-15, IL-17, TNF-α, IFN-α, IFN-γ, GM-CSF, MIP-1α, MIP-1β, IP-10, MIG, Eotaxin, RANTES, MCP-1, VEGF, GCSF, EGF, FGF-basic, HGF, BLyS and APRIL were analyzed. Results: A significant increase was seen in the serum levels of BLyS (p=0.0001) after rituximab therapy, while IL-12 (p=0.0002), IL-1RN (p=0.0001), IL-2R (p=0.0001), IL-1β (p=0.02), IL-7 (p=0.02), IL-10 (p=0.02), and MIG (p=0.05) all significantly decreased. All other cytokines/receptors remained unchanged. Higher pretreatment serum levels of IL-2R (p=0.008) and IL-12 (p=0.001) correlated with a shorter TTP. Furthermore, elevated serum IL-2R levels pretreatment correlated with a lack of response to rituximab (p=0.03). Differences in overall survival could not be determined due to the fact that only 8 patients enrolled in the study have died. Because serum IL-2R levels correlated with response and TTP, we measured the cell surface expression of IL-2R in the tumor by flow cytometry. IL-2R was detected on a subpopulation of CD4+ T-cells in all specimens tested (n=14), and on malignant B-cells in 5 cases (36%). Conclusions: Pretreatment serum levels of IL-2R and IL-12 are important prognostic factors for response to therapy or TTP in follicular lymphoma patients treated with rituximab. Furthermore, serum levels of BLyS, IL-1RN, IL-7, IL-10, IL-1β and MIG also change after rituximab treatment. Targeting these cytokines may therefore provide additional clinical benefit to patients treated with rituximab.

Abstract Serum BLyS levels have been found to be elevated in a number of immune disease models and there is increasing evidence that this may correlate with pathogenesis of various B cell related disorders including B cell malignancies. While it is clear that BLyS expression is required for normal B cell development and homeostasis, the exact source of BLyS in these scenarios and definition of the mechanisms that control BLyS expression remain to be fully elucidated. Serum BLyS levels are elevated in a number of B cell malignancies known to have a familial incidence. Therefore, we sought to determine if there was any correlation between serum BLyS levels and family history of B cell cancers. In our initial studies we examined the serum BLyS levels in patients with sporadic vs. familial B-cell chronic lymphocytic leukemia (B-CLL; near relative with B-CLL, multiple myeloma, or non-Hodgkin lymphoma), and normal age-matched controls. In the normal controls (n=50), the mean serum BLyS level was 12.7 ng/ml, and we found that 4/50 (8%) had BLyS levels exceeding 20 ng/ml. In the sporadic CLL cohort (n=52), the mean serum BLyS level was 18.3 ng/ml, and we found that 5/52 (10%) had BLyS levels exceeding 20 ng/ml. In striking contrast, in the familial CLL cohort (n=24), the mean serum BLyS levels was 33.4 ng/ml, and we found that 11/24 (46%) had BLyS levels exceeding 20 ng/ml. The percentage of patients with elevated BLyS levels, as well as the mean BLyS levels in the familial CLL cohort compared to the normal controls, was significantly higher (mean, p=0.002) and suggests that elevated BLyS levels may correlate with familial CLL. Because of the correlation between BLyS levels and family history B cell malignancies, we next wanted to determine if there was a common underlying genetic event influencing BLyS expression in this group of patients. We began by sequencing the BLyS promoter in 19 patients with B-CLL and 11 normal controls. We identified 2 sites that were polymorphic, −661 A/G and −871 C/T. The −871 T/T genotype has been previously reported to be expressed at increased frequency in SLE patients and is associated with elevated BLyS mRNA levels. Using RFLP analysis we examined the presence of the two polymorphisms in our control, sporadic, and familial CLL cohorts. In the control group (n=50) we found that at −871, C/C (wildtype) was expressed in 24%, C/T in 54%, and T/T in 22% of patients. Similarily, in the sporadic CLL group (n=35) we found that at −871, C/C was expressed in 29%, C/T in 57%, and T/T in 14%. In the familial group (n=24) we found that at −871, C/C was expressed in only 8%, C/T in 67%, and T/T in 25%. These data suggest a decreased representation of −871 C/C in the familial group. No significant changes were observed between the three groups at the −661 A/G locus. Additionally, we found that none of the patients with BLyS levels exceeding 20 ng/ml expresses C/C at −871. In summary, our data suggest that BLyS levels are elevated in patients with familial CLL relative to both normal controls and individuals with sporadic CLL and that elevated BLyS levels may correlate with the presence of a T at −871 in the BLyS promoter.

Abstract Abstract 3933 Poster Board III-869 Background Non-Hodgkin Lymphoma (NHL) is a malignancy of lymphocytes with few known risk factors identified to date. Members of the BCL2 and caspase gene families are known regulators of programmed cell death in these cells, and the t(14;18)(q32;q21) is the most commonly observed chromosomal translocation in NHL, a somatic event which results in constitutive BCL2 expression and inhibition of apoptosis. Further, recent pooled analyses of three case-control studies reported gene level associations for both BCL2L11 (Cancer Epidemiol Biomarkers Prev 2009;18:1259) and CASP9 (Blood 2009;114:264) with NHL risk. We therefore evaluated the hypothesis that germline variation in genes from the apoptosis pathway is associated with risk of developing NHL. Methods We genotyped 226 single nucleotide polymorphisms (SNPs) within 36 candidate BCL2-family and capsase-family member genes within the apoptosis pathway in a clinic-based study of 441 newly diagnosed NHL cases (within 9 months of first NHL diagnosis) and 475 frequency matched controls from Minnesota, Iowa, and Wisconsin who were seen at the Mayo Clinic from 2002-2005. Tagging SNPs were selected from HapMap for the following candidate genes: BCL2; BCLAF1; BCL2LA1; BCL2L1, 2, 10, 11, 12, 13, 14; BAD; BAX; BAG1, 3, 4, 5; BAK1; BID; BIK; BNIP2, 3; HRK; CASP1 – CASP10; APAF1; BIRC3; AIF1; and DFFB. Genotyping was completed using the ParAllele (now Affymetrix) Immune and Inflammation SNP panel, supplemented with 9 SNPs from a custom Illumina OPA. SNP call rate and per person call rate were >95% for all SNPs evaluated. The most prevalent homozygous genotype was used as the reference group, and each SNP was modeled individually as having a log-additive effect in a logistic regression model adjusted for age, sex, and residence. We used principal components analysis to assess the association with NHL risk at the gene level. Genes at p<0.05 were declared statistically significant, as were SNPs at p<0.05 from significant genes. Results The mean age at diagnosis for cases was 60.1 years, and 58% were male; among controls, the mean age at enrollment into the study was 61.7 years, and 55% were male. The most common NHL subtypes were chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL, 29%), follicular lymphoma (FL, 27%), and diffuse large B-cell lymphoma (DLBCL, 16%). In gene level analyses, BCL2L11 (also know as BIM) (p=0.0019), BLCAF1 (p=0.0097), BAG5 (p=0.026), and CASP9 (p=0.0022) were statistically significant at p<0.05. For BCL2L11, 2 of the 5 tagSNPs (both intronic) were significant at p<0.05 (rs6746608 and rs12613243). Both genotyped BCLAF1 tagSNPs (rs797558 and rs703193, both intronic) were significant, as was the single genotyped BAG5 tagSNP (rs7042474) from the non-coding region interval of an mRNA transcript. Three of the 7 genotyped CASP9 tagSNPs were significant (rs6685648, rs2020902, rs2042370, all intronic). Similar associations (as assessed by ordinal odds ratios) were observed for significant SNPs from BCLAF1, BAG5, BCL2L11 and CASP9 within the subtypes of CLL/SLL, FL, and DLBCL; however, caution is warranted in interpreting the subtype results due to small sample sizes. Conclusions Three genes from the BCL2 family (BCL2L11, BCLAF1, and BAG5) and one gene from the caspase family (CASP9) were associated with risk of NHL. This confirms gene level results for BCL2L11 and CASP9 in NHL overall and suggests a role for additional BCL2 family members in NHL etiology. In addition to extending these results to other populations, investigation of the functional significance of these genes and consideration of their upstream regulators and downstream targets should assist in clarifying the role of this pathway in lymphomagenesis. Furthermore, in the era of targeted therapeutics, identification of genetic variation in the apoptotic pathway may also assist in predicting prognosis as therapies targeting this pathway are developed. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3929 Poster Board III-865 In addition to providing prognostic information, gene expression profiling studies have helped to elucidate the putative cell of origin (e.g. activated or germinal center B cell) in diffuse large B-cell lymphoma. With the exception of angioimmunoblastic T-cell lymphomas, which are thought to derive from follicular helper T cells, little is known about the cell of origin for the most common peripheral T-cell lymphoma (PTCL), PTCL-unspecified (PTCL-U). Following appropriate antigenic stimulation, naïve CD4+ T cells may terminally differentiate into effector cells, defined by the production of specific cytokines, including IL-4/IL-10 producing Th2 cells. We have previously demonstrated that IL-10, produced by malignant T cells, is systemically elevated in the serum of patients with PTCL and contributes to the suppression of host anti-tumor immunity. Murine studies have demonstrated that the transcription factor GATA-3 is both critically important for IL-10 transcription and is required for the differentiation of Th2 cells. Therefore, we hypothesized that a subset of PTCL-U may be Th2-derived and express GATA-3. To examine this possibility, PTCL-U cases with adequate paraffin-embedded tissue were identified from a single institution (n=46) and immunohistochemically stained for GATA-3 expression. More than 10% of tumor cells expressed GATA-3 in 17 (37%) of the 46 cases examined. Follow up data sufficient to determine overall survival was available for 43 of these patients, in whom the expression of GATA-3 was associated with a poorer overall survival. Patients with GATA-3 negative tumors (n=27) had a median overall survival (OS) of 3.8 years, whereas patients with GATA-3 positive tumors (n=16) had a median OS of 0.7 years (p=.002). Among low-intermediate risk patients, as defined by the International Prognostic Index (IPI), GATA-3 expression was associated with inferior median overall survival (<12 months, p<.001). IL-10 production may explain the adverse impact of GATA-3 expression on OS in PTCL-U, as GATA-3 plays a central role in IL-10 transcription in normal T cells. To determine whether it may have a similar role in malignant T cells, we identified a PTCL cells line (SU-DHL-1) that highly expressed GATA-3 by intracellular flow cytometry. We next transfected these cells with a negative control or GATA-3 specific siRNA and demonstrated that transfection with GATA-3 siRNA significantly decreased GATA-3 expression in these cells. Following knockdown of GATA-3 expression, we measured both cell proliferation by 3H-TdR incorporation and IL-10 production by ELISA. No significant difference in cell proliferation was observed (n=4, p=0.2), whereas an approximately 50% reduction in IL-10 production was observed (n=3, p=.008) following inhibition of GATA-3 expression. Therefore, GATA-3 expression in malignant T cells may promote the production of IL-10, thus impairing host anti-tumor immunity. Immunomodulatory drugs (IMiDs), like lenalidomide, may downregulate GATA-3 expression in normal T cells. Therefore, we sought to determine whether lenalidomide may inhibit IL-10 production in normal and malignant T cells. T cells obtained from normal donors were activated with anti-CD3 and treated with either DMSO or lenalidomide (10 μM). Intracellular staining for both IL-10 and IL-2 was performed 3 days later. In DMSO control treated cells, 1.0% of cells expressed IL-10 and 12% expressed IL-2. In contrast, in lenalidomide treated cells, only 0.3% of cells expressed IL-10 and 17% expressed IL-2 (representative of at least 4 independently performed experiments). Similar results were obtained using T cells from a patient with Sezary Syndrome. We next treated SU-DHL-1 cells with DMSO or lenalidomide (0.1, 1.0 and 10 μM) and measured both cell proliferation by 3H-TdR incorporation and IL-10 production by ELISA. Significant inhibition of SU-DHL-1 proliferation was only observed when cells were treated with 10 μM lenalidomide. In contrast, significant inhibition of IL-10 production was observed in the presence of 1 μM and 10 μM lenalidomide (p<.01). Collectively, the data presented demonstrates that GATA-3 promotes the production of IL-10 by malignant T cells and is an adverse prognostic factor in PTCL-U. Given its immunomodulatory properties, including inhibition of IL-10 production, lenalidomide represents a promising therapeutic agent in PTCL-U. Disclosures: No relevant conflicts of interest to declare.

Abstract Peripheral blood infused total autograft absolute lymphocyte count (A-ALC) correlates with day 15 absolute lymphocyte count and is an independent prognostic factor for survival after autologous stem cell transplantation (ASCT) for non-Hodgkin lymphoma (NHL). Factors to enhance A-ALC collections are not well defined. We hypothesize that the number of peripheral blood apheresis collections (PBAC) directly correlates with A-ALC. 190 consecutive NHL patients who underwent ASCT at the Mayo Clinic between 1993 and 2001 were analyzed. The primary end point of the study was to assess the correlation between the number of PBAC and A-ALC. The secondary end point was to determine if the number of PBAC affected survival post-ASCT. Of the 190 patients, 18 patients underwent 1 PBAC, 23 patients 2 PBAC, 50 patients 3 PBAC, 37 patients 4 PBAC, 50 patients 5 PBAC, and 12 patients had ≥ 6 PBAC. There was no association between the number of PBAC and the number of CD34+ stem cells collected (p= 0.25). A strong association between number of PBAC and A-ALC (Kruskall Wallis test, p <0.0001)(Figure 1) was identified. Using a cut-off of 4 PBAC, superior overall survival (OS) and progression-free survival (PFS) were observed for patients that underwent 4 PBAC or more compared to patients that underwent less than 4 PBAC (86 months vs 18 months, p <0.0001; 76 months vs 10 months, p <0.0001, respectively). Multivariate analysis demonstrated PBAC ≥ 4 is an independent prognostic factor for OS (RR = 0.654, 95%CI: 0.529–0.804, p< 0.0001) and for PFS (RR = 0.682, 95%CI: 0.561–0.826, p< 0.0001) when compared with other significant factors including performance status, lactate dehydrogenase and extra nodal disease. These data suggest that increasing the number of PBAC beyond the minimum number required to meet CD34+ collection targets may result in improved overall and progression-free survival mediated by an increase in autograft absolute lymphocyte count.

Abstract Abstract 587 Background: The phosphatidylinositol 3-kinase/mammalian target of rapamycin (mTOR) signal transduction pathway controls cell proliferation and survival. Everolimus is an oral agent targeting raptor mTOR (mTORC1). The trial's goal was to determine the anti-tumor activity and safety of single-agent everolimus in patients with relapsed/refractory Waldenstrom's macroglobulinemia (WM). Patients and Methods: Eligible patients had measurable disease (IgM monoclonal protein >1000 mg/dL with >10% marrow involvement or nodal masses >2 cm), a platelet count ≥75,000 × 106/L, a neutrophil count ≥1,000 × 106/L, and a creatinine and bilirubin ≤2x laboratory upper limit of normal. Patients received everolimus 10 mg PO daily and were evaluated monthly. Tumor response was assessed after cycles 2 and 6 and then every 3 cycles until progression. Results: 50 pts were treated. The median age was 63 years (range, 43-85). The overall response rate (CR+PR+MR) was 70% (95% CI: 55-82%), with a PR of 42% and 28% MR. The median duration of response and median progression-free survival (PFS) has not been reached. The estimated PFS at 6 and 12 months is 75% (95%CI: 64-89%) and 62% (95%CI: 48-80%), respectively. Grade 3 or higher related toxicities were observed in 56% of patients. The most common were hematological toxicities with cytopenias. Pulmonary toxicity occurred in 10% of patients. Dose reductions due to toxicity occurred in 52% of patients. Conclusions: Everolimus has high single-agent activity with an overall response rate of 70% and manageable toxicity in patients with relapsed WM, and offers a potential new therapeutic strategy for this patient group. Disclosures: Ghobrial: Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Richardson:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keryx: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Treon:Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Genentech: Honoraria, Research Funding, Speakers Bureau. Witzig:Novartis: Research Funding.

Abstract Abstract 4359 Routine serial chimerism analysis after allogeneic stem cell transplantation (Allo-SCT) has been used as a risk factor for post-Allo-SCT cancer relapse. In non-Hodgkin lymphoma (NHL) patients treated with autologous peripheral blood hematopoietic stem cell transplantation (APHSCT), a specific predictor during routine follow-up that could be used to ascertain risk for post-APHSCT relapse has not been identified. Thus, we set out to investigate if absolute lymphocyte count (ALC) measured at post APHSCT follow-up could serve as a marker of post-APHSCT NHL relapse. ALC was obtained at the time of confirmed relapse at follow-up and at last no evidence of relapse follow-up. From 1993 until 2005, 269 patients treated with APHSCT for diffuse large B-cell lymphoma (DLBCL), were included in this study. Patients at last follow-up with no relapse (N=137) had a higher ALC compared with those with confirmed relapsed at follow-up post-APHSCT (N= 132) [median ALC x 109/L of 1.66 (range: 0.13-3.69) vs 0.71 (range: 0.03-4.75), p <0.0001, respectively]. ALC at follow-up was a strong predictor for relapse with an area under the curve (AUC) = 0.86 (p<0.0001). An ALC of 1.0 × 109/L was identified as the optimal cut-off point. An ALC < 1.0 × 109/L at the time of confirmed relapse had a positive predictive value of 89% and a positive likelihood ratio of 8.4 to predict relapse post-APHSCT. Patients with an ALC ≥ 1.0 × 109/L (N = 147) had a cumulative incidence of relapse of 19% versus 92% for patients with an ALC < 1.0 × 109/L (N = 122) (p<0.0001) at follow-up post-APHSCT. This study suggests that ALC at follow-up can be used as a marker to assess risk of DLBCL relapse during routine follow-up after APHSCT. Disclosures: No relevant conflicts of interest to declare.

Abstract Purpose: Primary colorectal large B-cell lymphoma is rare and accounts for less than 1% of all malignancies in the colon. Standard treatment for limited stage diffuse large B-cell lymphomas (DLBCL) includes systemic therapy combined with involved field radiation therapy. However, radiation therapy may often not be feasible in patients with primary colon lymphoma. For primary DLBCL of the colon particularly the cecum, surgical resection prior to the administration of systemic chemotherapy has been considered to improve local control. The goal of this study was therefore to determine whether surgical resection improves the outcome of patients with primary DLBCL of the colon. Methods: Clinical information and outcomes on all the patients with primary DLBCL of the colon seen at Mayo Clinic, Rochester, between January 1980 and June 2005 were retrospectively reviewed. Results: There were 28 patients identified with primary colon DLBCL. Pre-existing conditions like colon polyps, Crohn’s disease and diverticulosis were uncommon. The most common presenting symptom was bleeding per rectum seen in 13 patients (46.5%). Other symptoms included abdominal pain, diarrhea and anemia. All patients had early stage disease (stage1–22 patients, stage2–6 patients) at diagnosis. Of the 28 patients, 16 underwent initial surgery followed by chemotherapy, 7 were treated with chemotherapy alone, and 5 patients had inadequate data to determine time to progression or overall survival. Chemotherapy was anthracycline based, with the most common regimen being CHOP (Cyclophosphamide, Doxorubicin, Vincristine, Prednisone). There was no difference in overall survival or time to progression between the 16 patients who received combined modality therapy compared to the 7 patients who received chemotherapy alone. Of the 16 patients who underwent surgical resection followed by chemotherapy, all 5 patients who relapsed, relapsed at other sites in the colon. Conclusion: Surgery as part of combined modality therapy did not appear to improve the outcome of patients with primary DLBCL of the colon. Systemic chemotherapy with an anthracycline-based regimen in combination with rituximab is therefore likely to be sufficient treatment for these patients. Follow-up for these patients should include a colonoscopy to monitor for recurrences at other sites in the colon.