Citations

Abstract Small lymphocytic lymphoma (SLL) is an incurable indolent lymphoma, and there are relatively few prognostic biomarkers for this important NHL subtype. We evaluated the hypothesis that inherited variability in cytokine and immune-related genes was associated with overall survival in SLL. We genotyped 73 SNPs in 44 candidate genes in 140 SLL patients aged 20–70 years who participated in a population-based case-control study conducted from 1998–2000 through the Surveillance, Epidemiology, and End Results (SEER) cancer registries in Detroit, Seattle, Iowa, and Los Angeles. DNA was extracted from a venous blood sample or mouthwash buccal cell sample. All genotyping was conducted at the National Cancer Institute Core Genotyping Facility using the Taqman platform. Histology, stage, presence of B-symptoms, first course of therapy, date of last follow-up, and vital status were derived from linkage to registry databases at each study site in the spring of 2005. Cox proportional hazards analysis was used to estimate the hazard ratio (HR) and 95% confidence interval for the association between individual SNPs and overall survival, adjusted for age, demographic and clinical factors. Multiple simultaneous modeling strategies were used to identify the best summary multi-SNP risk score to predict survival. At last follow-up, there were 45 deaths in 140 patients (32%). The median follow-up of the 95 surviving patients was 58 months (range 24–75 months). In multivariate modeling, SNPs in IL13 (rs1800925; HRCC=2.36, 1.24–4.49), IL7R (rs1494555; HRGG =2.20, 0.84–5.76), and TNF-alpha (rs1800630; HRAC/AA=1.73, 0.95–3.17) were the strongest and most robust predictors of survival. Two or more deleterious genotypes from these three SNPs increased the risk of death (HR=2.2, 1.2–4.1) compared with one or fewer deleterious genotypes (p=0.009). Three groups (low, intermediate, and high risk) were defined by combining the SNP score and a clinical/demographic score. The 5-year Kaplan-Meier survival estimates for these groups were 85%, 65%, and 11%, respectively. Compared to patients with a low risk score, patients with intermediate (HR=2.5, 1.2–5.1) or high (HR=11, 4.3–27.7) risk scores had poorer overall survival (p=3.9 x 10−8). Our preliminary results suggest that SNPs in IL13, IL7R, and TNF-alpha alone and in combination predict overall survival in SLL, lending support to the hypothesis that host genetic background is a promising class of prognostic biomarkers in SLL.

Abstract Tumors arise and evolve by iterative steps of mutation, subclonal selection, and clonal expansion due to growth advantage of the fittest subclones and external mutation induction and selection pressure from radiation and drug therapies. Various studies have shown that greater clonal complexities in primary tumors are correlated with poor clinical outcome of tumor progression and/or drug resistance. Recently, we have reported that very few of the driver mutations, all of which were clonal, detected in primary diffuse large B-cell lymphoma (DLBCL) were associated with DLBCL outcome as measured by 24-month event-free survival (EFS24). In the current project, we identified and studied subclonal mutations in primary DLBCL tumors and assessed their associations with EFS24, as well as the role of activation-induced cytidine deaminase (AID) in genomic mutations occurred in DLBCL tumors. The detection of subclonal mutations is still a significant bioinformatics challenge. In addition, identification of clonal mutations in samples with lower tumor purities faces similar challenges due to the low concentration of reads supporting the mutant alleles. The current methods of somatic mutation calling are not sufficiently sensitive to identify the low concentration mutations in tumor DNA sequencing data. We implemented a bioinformatics workflow for low-concentration and subclonal mutation detection which is based on the positional read pile-up data and a back-fill approach (PUB). The pile-up files were first generated using the re-aligned and re-calibrated BAM files after read alignment using Burrows-Wheeler Aligner (BWA). The variant positions with alternative bases were annotated by attributes defined in the Variant Quality Score Recalibration (VQSR). PUB then used a boosting method and a generalized linear model (GLM) to train a model of 'good quality' variants using common variants from HapMap, and prioritized and called clonal and subclonal variants based on the trained model. The VQSR attributes related to alternative allele depth were less-weighed in order to call subclonal mutations. The somatic mutations were then identified by Fisher's Exact Test using sequencing depths of the reference and alternative alleles from paired tumor and germline sequencing data. The exome sequencing data of paired tumor and peripheral blood from 48 newly diagnosed DLBCL patients were analyzed using PUB. Thirty-six of the 48 patients achieved EFS24 with the other 12 patients experienced primary treatment failure. Most of the tumors studied had tumor purities between 40-70%. PUB identified substantially higher number of somatic mutations, both clonal and subclonal, compared to those detected using existing somatic callers. We observed that the prevalence of mutations in previously reported driver genes were higher using thresholds of mutation concentration ≥ 5% and Fisher's Exact Test p ≤ 0.05, including EZH2 (mutated in 26% of DLBCL tumors analyzed by PUB, compared to 12.7% as previously reported), MLL2 (72% vs. 31%), CD79B (22% vs. 14%), TNFRSF14 (36% vs. 20%), MEF2B (22% vs. 16.4%), CARD11 (46% vs. 21.8%), and MYD88 (18% vs. 11%). In addition, other genes involved tumorigenesis that have not been previously linked to DLBCL also harbored both clonal and subclonal mutations with substantial prevalence, including FGFR3 (12%), KIT (24%), and ATM (28%). Furthermore, association of genes displaying clonal and subclonal mutations with EFS24 identified potential biomarkers for DLBCL outcome. Among these, two genes EPGN and ASTE are involved in epithelial growth factor receptor signaling and had association p values of 0.0001 and 0.0016, respectively. The oncogene MAFB was also associated with EFS24 (p= 0.0016). We searched for AID induced mutations among all identified variant positions and concluded that there was no evidence of AID site enrichments compared to a simulated data set. In summary, we developed and applied a sensitive bioinformatics pipeline for the identification of both clonal and low concentration somatic mutations in primary DLBCL exome sequencing data which further revealed the clonal complexity of the primary DLBCL tumors. Several of the genes were identified as potential biomarkers for DLBCL outcome. Disclosures Maurer: Kite Pharma: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding. Cerhan:Kite Pharma: Research Funding.

Abstract Background: Obesity has been associated with risk of non-Hodgkin lymphoma (NHL) in several recent studies. However, the effect of weight gain during adulthood, a potentially modifiable risk factor, on the incidence of NHL is not clear. We therefore examined the association of weight gain since age 18 years with the risk of NHL among older women. Methods: We examined this association in the Iowa Women’s Health Study, a prospective study of 37,762 Iowa women aged 55 to 69 years at enrollment in 1986. Lifestyle and other risk factors, including weight at age 18 and at enrollment, were self-reported on a mailed questionnaire. We defined stable weight as no increase in weight or up to a 10% weight loss from age 18 to enrollment, while percent weight gain was divided into tertiles based on the distribution observed in the cohort. NHL incidence through 18 years of follow-up was ascertained by linkage with the Iowa SEER Cancer Registry. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) of percent weight gain with NHL incidence, adjusting for age (Age-adjusted model) and age, marital status, farm residence, transfusion history, diabetes, use of hormone replacement therapy, alcohol use, smoking, and intake of red meat and fruits (Multivariate model). Results: The mean age of the women in the cohort in 1986 was 62.1 years. During 593,474 person-years of follow-up, 379 incident cases of NHL were observed. The mean age at diagnosis was 72.6 years (range 58–87 years). The main results are reported in the table. Similar results were found for absolute weight gain. Stratification of these results on body mass index at age 18 (using a cutpoint of 21 kg/m2) showed similar results, with the exception of >10% weight loss for women with a BMI of <21 at age 18 where we could not estimate a RR (no cases observed). Conclusions: Weight gain or large weight loss (>10% of body weight) during adulthood were both associated with increased risk of NHL, although the RRs for percent weight gain were not statistically significant and there was no dose-response. This study suggests another potential benefit of avoiding adult weight gain, although further studies are needed to confirm these novel findings. Association of percent weight change during adulthood (age 18 to age 55–69 years) and risk of NHL % Weight Change NHL Cases Person-years Age-Adjusted RR(95% CI) Multivariate RR (95% CI) >10% weight loss 15 17053 2.06 (1.05–4.02) 2.02 (1.03–3.95) Stable 20 45973 1 (reference) 1 (reference) 0–18.2% gain 115 175883 1.50 (0.94–2.42) 1.50 (0.93–2.41) 18.3–34.8% gain 119 176258 1.54 (0.96–2.47) 1.53 (0.95–2.47) >34.8% gain 110 178308 1.40 (0.87–2.25) 1.32 (0.82–2.14).

Abstract DLBCL is a curable subtype of non-Hodgkin lymphoma, although a significant number of patients do not achieve a remission or they relapse with conventional chemotherapy. While clinical variables (e.g., IPI), tumor (somatic) genetic alterations, and gene expression profiling have all been shown to predict outcome, there remains a need for additional prognostic biomarkers. One understudied class of biomarkers is host genetic background. We evaluated the hypothesis that germline variability in 73 SNPs from 44 candidate immune genes was associated with overall survival in DLBCL. We addressed this hypothesis in 365 DLBCL patients aged 20–70 years who participated in a population-based case-control study conducted from 1998–2000 (prior to the use of R-CHOP) through the Surveillance, Epidemiology, and End Results (SEER) cancer registries in Detroit, Seattle, Iowa, and Los Angeles. Germline DNA was extracted from a venous blood sample or mouthwash buccal cell sample, which was collected a median of 4.8 months after diagnosis in this population-based study. All genotyping was conducted at the National Cancer Institute Core Genotyping Facility using the Taqman platform, and was successful in over 95% of the DNA samples for the SNPs evaluated. Histology, stage, presence of B-symptoms, first course of therapy, date of last follow-up, and vital status were derived from linkage to registry databases at each study site in the spring of 2005. Cox proportional hazards analysis was used to evaluate the association between individual SNPs, adjusted for age, demographic and clinical factors. Parallel modeling strategies were used to identify the best summary multi-SNP risk score to predict survival. At a median follow-up of 56 months (range, 27-78 months) for surviving patients, there were 96 deaths in 365 patients (26%). In multivariate modeling, SNPs in IL1A (rs1800587; HRCT/TT=1.90, 1.26–2.87), IL6 (rs1800795; HRGG=1.48, 0.99–2.23), IL-10 (rs1800896; HRAG/GG=1.48, 0.91–2.38), and IFNGR2 (rs2070385; HRAG/GG=1.35, 0.86–2.11) were the strongest and most robust predictors of overall survival. A summary score of the number of deleterious genotypes from these four genes in combination with clinical and demographic variables was strongly associated with survival (p=9.3 x 10−12); Kaplan-Meier 5-year survival estimates for low, intermediate, and high risk patients were 89%, 68%, and 47% respectively. In conclusion, host genetic background as measured by germline polymorphisms in immune genes including IL1A, IL6, IL10, and IFNGR2 were associated with overall survival in DLBCL after accounting for clinical and demographic factors. These promising results require confirmation and need further evaluation in patients treated with R-CHOP in conjunction with tumor and other prognostic biomarkers.

Abstract Abstract 1540 Background: Diffuse Large B-cell Lymphoma (DLBCL) is the most common lymphoma in the western world. Outcomes have improved with the standard initial therapy of rituximab and anthracyline based chemotherapy (immunochemotherapy). However, 20–40% of patients will either fail to achieve remission or relapse following initial immunochemotherapy. Most relapses occur early, and long-term outcome of relapsed/refractory patients is generally poor despite salvage regimens and stem cell transplant. Traditionally, studies for DLBCL have been evaluated using progression-free and/or overall survival. However, the event rate in DLBCL slows significantly approximately 12–18 months after diagnosis, and late events are often due to competing (non-DLBCL related) risks, especially in older patients. Here we examine outcome of DLBCL patients based on their event status at 12 months. Methods: Newly diagnosed DLBCL patients were prospectively enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER). Clinical data were abstracted from medical records using a standard protocol. Patients were actively followed for events (progression, re-treatment, or death due to any cause) and overall survival (OS). Event-free status at 12 months after diagnosis (EFS12) was assessed as a dichotomous variable. Cause of death was determined by medical record and death certificate review using prospectively determined definitions. Expected survival was based on age and sex matched survival using the Minnesota population death rates. Confirmation cohorts were from a Lyon, France hospital based registry and NCCTG clinical trial N0489. Results: 680 patients with newly diagnosed DLBCL and treated with rituximab + anthracycline based chemotherapy were enrolled in the MER from 2002 to 2009. The median age was 62 years (range 18–92). 53% were male. At a median follow-up of 59 months (range 8–116), 266 patients (39%) had an event and 188 patients (28%) died. 162 patients (24%) had an event in the first 12 months after diagnosis, comprising 60% of all events. Patients with an event in the first 12 months had poor survival with death almost exclusively due to disease (Figures 1a, 2a). In contrast, patients who were event-free at 12 months had comparable survival to the age and sex matched general population (Figure 2b) and were more likely to die of other causes than DLBCL (Figure 1b). Overall survival rates by EFS12 status were validated in patients from a French hospital-based registry (N=265) and the NCCTG N0489 clinical trial (N=87) with additional replication studies underway. Conclusions: DLBCL patients who are event-free at 12 months after diagnosis have an excellent prognosis with an overall survival similar to that of an age- and sex- matched general population and are more likely to die of other causes than DLBCL. This finding has implications for clinical management, new clinical trials, and follow-up testing in this patient population. In contrast, patients with an event within the first 12 months after diagnosis have a poor prognosis with almost all deaths secondary to DLBCL. EFS status at 12 months identifies patients with poor outcomes due to disease. This can be utilized as an endpoint in biologic studies and clinical trials to address early treatment failures. EFS status at 12 months should be incorporated into prognostic models to identify high risk patients in newly diagnosed DLBCL. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1604 Background EBV (+) DLBCL of the elderly is a lymphoproliferative disorder recently included as a provisional entity in the 2008 WHO classification of lymphoid tumors. Defined as EBV (+) DLBCL in patients over the age of 50 years without known immunosuppression, information is evolving in this entity. To date, the true incidence of EBV (+) DLBCL in adults remains imprecisely determined and may vary regionally. This study sought to determine the incidence, presenting clinical characteristics, and outcome of EBV (+) in an unselected cohort of DLBCL patients enrolled in a prospective observational study. Methods The University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER) is a prospective, longitudinal observational study designed to collect information on patterns of care and outcomes for patients with newly diagnosed lymphoma. Patients seen at the Mayo Clinic, Rochester MN and the University of Iowa within 9 months of their initial diagnosis of lymphoma are offered enrollment. HIV (+) patients are excluded. Baseline patient reported data, clinical data and initial management are collected using a standard protocol and a central pathology review is performed. After enrollment, patients are actively followed for events (disease progression, retreatment, and death) and disease related comorbidities. Tissue Micro Arrays (TMA) are constructed on available primary biopsy specimens. Epstein Barr Encoded RNA (EBER) EBV testing was performed by in-situ hybridization, and scored by an expert hematopathologist. EBER reactivity in more than 30% of malignant cells were required for EBV(+) designation. All DLBCL patients from the MER with available TMA excluding primary mediastinal DLBCL and post transplant lymphoproliferative disorders (PTLD) are included in the current analysis. Event free survival (EFS) was defined as time from diagnosis until recurrence, retreatment, or death due to any cause. Results 184 newly diagnosed DLBCL patients with available TMAs were enrolled in the MER from 2002–2009. The median age at enrollment was 62 (range 18–89) and 57% were male. 89.7% were treated with immunochemotherapy. At a median follow-up of 66 months (range 1–116), 80 patients (43%) had an event which included 59(32%) deaths. TMA testing was positive for EBV in 13 (7 %) samples with an even distribution among age groups. There was a trend toward higher percentage of stage III/IV disease (85 vs 57%, p = 0.052), and BM involvement (46 vs 16%). EBV (+) was not associated with other extranodal disease or further identifiable differences in presenting clinical characteristics. Controlling for IPI, the hazard ratio for EFS among EBV+ in DLBCL pts over 50 was 0.41 (95% CI = 0.13–1.32) p = 0.14. EFS and OS curves for pts over 50 are shown below. There were no events or deaths in the 4 EBV+ pts under age 50. Conclusions EBV+ DLBCL represents a small proportion of DLBCL patients presenting for care to our academic medical centers, consistent with reports from other regions. Substantial unique clinical characteristics at presentation for those pts with EBV+ disease were not identified, and outcomes were no worse than EBV (−) counterparts. Given the apparent regional differences in reports of EBV(+) DLBCL of the elderly, future clinical series will need to establish a more precise definition or determine more distinctive features to justify adoption of EBV(+) DLBCL of the elderly as a full entity in the WHO classification. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1546 Background: Follicular lymphoma (FL) is an incurable disease with an undefined optimal management strategy. Global priorities in goals of care are avoidance of death and transformation to aggressive subtypes. Retrospective series, – most including patients diagnosed before ubiquitous rituximab use, - describe diverse rates of transformation with a common consensus of 3% per year, and with a median survival post transformation of less than 2 years. This study sought to characterize transformation events in a prospective observational series begun after diffusion of early rituximab use in FL. Methods: Newly diagnosed FL patients were prospectively enrolled in the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER) from 2002–2009. Clinical data were abstracted from medical records using a standard protocol. Patients were actively followed for retreatment, transformation, and death. Inclusion criteria for this analysis were initial diagnosis of grade I-IIIa FL. Exclusion criteria for this cohort include composite diffuse large B-cell lymphoma (DLBCL), FL grade IIIb, or evidence of clinical or pathological transformation at the time of FL diagnosis. Transformation was defined as refractory/recurrent disease with either a) biopsy confirmed subtype of FLIIIb, DLBCL or higher grade B-cell lymphoma; or b) clinical indication of transformation (sudden rise in LDH, rapid discordant localized nodal growth, new involvement of unusual extranodal sites, new B symptoms or hypercalcemia). Risk of transformation was analyzed via time to transformation using a death as a competing risk. Time to transformation was defined as the date of initial FL diagnosis to date of transformation. Overall survival was defined as the date of initial diagnosis to date of death or last known follow-up for patients still alive. Results: There were 631 newly diagnosed grade I-IIIa FL patients with a median age at enrollment of 60 years (range 23–93). 54% were male. The most common types of initial therapy were observation (33%), rituximab (R) monotherapy (12%), alkylator based chemotherapy +/− R (22%), and anthracycline based chemotherapy +/− R (20%). At a median follow-up of 60 months (range 11–110), 79 patients had died, 311 patients had an event (death, progression, or retreatment), and 60 patients (9.5%) had transformed. Transformation was biopsy proven in 48 of the 60 patients (80%). The overall transformation rate at 5 years (TX5) was 10.7% (95% CI: 8.3%–13.8%) (Figure 1). Time to transformation was associated with a FLIPI score of 3–5 (HR=2.37, 95% CI 1.28–4.39, p=0.006), but was not significantly associated with other standard clinical characteristics. Risk of transformation was different in the common initial treatment groups with the highest rate in patients who were initially observed (TX5=14.4%) and lowest rate in patients who initially received R monotherapy (TX5=3.2%)(p=0.058). Outcome after transformation was inferior to MER subjects with de-novo diagnosed DLBCL (p<0.0001). The median overall survival from date of transformation was 44 months (95% CI: 22-NA). Survival after transformation was superior in patients who transformed greater than 18 months after FL diagnosis compared to patients who transformed earlier (5 yr OS =70% vs 20%) (p=7 ×10−5), and for those initially observed (median unreached) versus those patients who were initially treated with alkylator or anthracycline based chemotherapy (median survival of 11 months)( p=0.016). Conclusions: Follicular transformation rates in this modern large prospective observational study are similar to risk of death without transformation and slightly lower at 5 years than most previous reports. Post-transformation prognosis is substantially better than described in older series. These observed differences may be a function of the prospective nature of the study design, modern management strategies, or patient selection factors. Initial management strategies may influence the risk of transformation. Marked survival differences following early vs. late transformation suggest that these may be different biologic events. Disclosures: Link: Genentech: Consultancy, Research Funding; Celgene: Consultancy; Millenium: Consultancy. Johnston:Novartis: Consultancy.

Abstract Background: It is well established that the incidence of skin cancers in patients with CLL are significantly elevated compared to age- and sex- matched controls. However, little is known about the characteristics of CLL patients who develop skin cancer. Herein, we evaluate the associations of CLL clinical and prognostic characteristics, along with UV radiation exposure, with risk of first skin cancer following CLL diagnosis. Methods: Newly diagnosed CLL patients from Minnesota, Iowa, and Wisconsin were enrolled in the Mayo Clinic case-control study from 2002-2015 and systematically followed in the Iowa/Mayo Lymphoma SPORE. Clinical and prognostic CLL data were obtained from the Mayo Clinic CLL database, and skin cancer clinical data were abstracted from medical records using a standard protocol. The CLL international prognostic index (CLL-IPI) was computed using a weighted average of five independent CLL prognostic factors (IGHV mutational status, serum b2-microglobulin, Rai stage, age, and FISH 17p deletion/TP53 status). Self-reported history of midday sun exposure at various ages (birth to age 12; 13 to 21 years; 22 to 40 years, and 41+ years) was obtained from a risk factor questionnaire. For each age, we asked the extent of mid-day sun as: practically no exposure (under 3 hours per week), little exposure (4-7 hours per week), moderate exposure (8 to 14 hours per week) and extensive exposure (15+ hours per week). Midday sun exposure was modeled as an ordinal covariate. To evaluate associations with risk of skin cancer following CLL diagnosis, we calculated time from date of CLL diagnosis to date of first skin cancer, death, or last known follow-up. We used Cox regression analysis to estimate hazard ratios (HRs) and 95% CIs. CLL treatment was considered a time-dependent covariate. Results: Among 846 CLL patients enrolled, the median age at diagnosis was 63 years (range 28-91), 68% were male, 7% had Rai stage III-IV at diagnosis. Based on the CLL-IPI, 42% were categorized as low risk, 33% as intermediate risk, and 25% as high or very-high risk. 109 CLL cases (13%) had one or more reported skin cancers at or prior to CLL diagnosis. Melanoma was observed in 19 (2%) cases and non-melanoma was in 90 (11%) cases. At a median follow-up of 7 years from CLL diagnosis, 165 patients (20%) had one or more skin cancers after CLL diagnosis. Among these patients, 49 had skin cancer before CLL diagnosis. The most frequent skin cancer was squamous cell carcinoma (59%), followed by basal cell (31%), melanoma (5%), and Merkel cell (1%). 552 (65%) of the 846 patients returned a questionnaire. Significant associations of clinical and prognostic characteristics with risk of first skin cancer were observed for age (HR=1.35 per 10 year increase, 95% CI=1.17-1.56, P<0.001), male sex (HR=1.38, 95% CI 0.98-1.96, p=0.07), prior history of skin cancer (HR=4.19, 95% CI=2.98-5.88, P<0.001), and CLL-IPI (HR=1.26, 95% CI= 1.03-1.54, P=0.026, after adjusting for age, sex, and prior skin cancer). Of note, the risk of first skin cancer in those CLL patients categorized as very high via CLL-IPI had 2.28 fold risk (95% CI 1.02-5.11). Midday sun exposures for each of the ages considered showed no evidence of association with risk of first skin cancer (all P>0.05). 50 CLL patients were treated prior to first skin cancer following CLL diagnosis; we observed no evidence of association between treatment and risk of first skin cancer (HR=1.44, 95% CI= 0.93-1.92, P=0.12). Conclusion: CLL patients who are at an increased risk of skin cancer following CLL diagnosis are those who either have had a prior history of skin cancer or a more aggressive CLL disease at diagnosis, according to CLL IPI. Routine skin cancer screening is currently recommended for CLL patients. Our data suggest that more frequent screening would be particularly important among patients with aggressive CLL and who have a prior history of skin cancer. Unexpectedly, we found no evidence of association of skin cancer risk with UV radiation following CLL diagnosis or with CLL treatment. Further investigation is needed to determine whether other factors increase the risk of skin cancer following CLL diagnosis. Disclosures Shanafelt: Genentech: Research Funding; GlaxoSmithkKine: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding.

Abstract Abstract 149 Background. There are few established factors that predict risk of follicular lymphoma (FL) transformation, and only two studies have evaluated the role of germline genetic variation and risk of transformation. One study reported an association of a BCL6 SNP (397C>G) with risk of transformation, and a second study reported an association with rs6457327, which is in the HLA region of 6p21. This study evaluated the risk of FL transformation in the modern treatment era with germline SNPs that were previously reported to be associated with FL transformation (BCL6SNPs and rs6457327), along with SNPs (N=45) previously associated with either risk of FL or FL prognosis. Methods. Newly diagnosed FL patients were prospectively enrolled from 2002–2009 into the Molecular Epidemiology Resource of the University of Iowa/Mayo Clinic Lymphoma SPORE. Peripheral blood for genotyping was collected at enrollment, and clinical and treatment data were abstracted from medical records. All patients were actively followed for disease progression, retreatment, transformation and death. For this analysis, only FL patients with grade I-IIIa were included. Patients with composite DLBCL, FL grade IIIb, or other evidence of transformation at diagnosis were excluded. Transformation was based on either 1) biopsy confirmation of FL grade IIIb, DLBCL, or higher grade B-cell lymphoma; or 2) clinical indicators of transformation based on the published literature, including sudden rise in LDH, rapid discordant localized nodal growth, new involvement of unusual extranodal sites, new B-symptoms, or hypercalcemia. Genotyping was conducted using a custom Illumina iSelect panel. Cox regression was used to estimate Hazard Ratios (HRs) and 95% confidence intervals (CI) for individual SNPs with time to transformation, with death modeled as a competing risk. Each SNP was modeled with the most prevalent homozygous genotype used as the reference group, and each SNP was modeled as having a log-additive (per minor allele) effect in the regression model. An ordinal test was used to assess the trend, and p<0.05 was considered statistically significant. Results. There were 631 newly diagnosed grade I-IIIa FL patients, of whom 532 had DNA and were successfully genotyped. The median age at diagnosis was 60 years (range 23–93) and 53% were male. FLIPI distribution was 42% 0–1, 34% 2 and 24% 3–5. Initial therapies included observation (32%), rituximab (R) monotherapy (13%), alkylator-based chemotherapy +/− R (20%), and anthracycline-based chemotherapy +/− R (19%). At a median of 59 months of follow-up (range, 11–110), 58 patients died, 254 had an event (death, progression or retreatment) and 54 patients (10%) transformed. Transformation was biopsy proven in 43 of the 54 patients (80%). The SNP rs6457327 on chromosome 6p that was previously reported to be associated with transformation was positively associated with risk of transformation in our data (HR=1.40; 95%CI 0.97–2.04; p=0.07), although this association was weaker but still consistent with the prior report. Further, we evaluated additional typed SNPs from the HLA region of 6p, and found additional associations (p<0.05) with HLA-DRA (3 SNPs), HLA-DQA2 (2 SNPs), HLA-DOA (2 SNPs) and HLA-DPB1/HLA-DPA2 (2 SNPs), of which rs10484569 from HLA-DPB1/HLA-DPA2 was the most strongly associated with risk of transformation (HR=3.01; 95%CI 1.48–6.09; p=0.002). None of the BCL6 or other previously reported risk SNPs were associated with transformation. Of the SNPs previously associated with FL prognosis, only the FCGR2A rs1801274 (HR=1.41; 95%CI 0.94–2.10; p=0.09) and CD46 (CD46 molecule, complement regulatory protein) rs2466571 (HR=1.72; 95%CI 1.16–2.55; p=0.007) were associated with risk of transformation. For CD46, one additional SNP (rs2796269) was also associated with transformation (HR=0.61; 95%CI 0.40–0.95; p=0.03). Further adjustment for FLIPI score and treatment (observation versus all other) did not alter these associations. Conclusions. The previously reported association of rs6457327 with risk of transformation in the modern treatment era was replicated. In addition, several HLA loci and two FL prognosis SNPs were linked to transformation risk. The remaining published FL risk or prognosis SNPs were not associated with transformation. Our results support a role for germline genetic variation in the HLA region, FCRGR2A and CD46 in transformation of FL. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1525 Background: Nodular lymphocyte predominant Hodgkin Lymphoma (NLPHL) is a more indolent form of Hodgkin Lymphoma that is usually associated with favorable outcomes. However, a number of reports have shown a tendency of transformation to more aggressive types of lymphoma, typically diffuse large B-cell lymphoma (DLBCL). Long-term data on the incidence and outcomes of transformed NLPHL is lacking in the literature. The aim of this study was to evaluate incidence, risk factors and outcomes of DLBCL transformation in NLPHL in a cohort of patients followed at a single institution. Methods: The actively maintained Mayo Clinic Lymphoma Database includes all consenting consecutive patients with lymphoma seen at Mayo Clinic Rochester. This was used to retrospectively identify patients with NLPHL. The study was approved by the Institutional Review Board. Pathology was reviewed by a hematopathologist and all transformations were histologically confirmed by WHO criteria. The clinical characteristics, therapy and outcomes of patients with NLPHL and DLBCL transformation were analyzed. The chi-square test was used to compare variables. Risk of progression was calculated using a person-year approach. Survival and freedom from transformation were estimated and compared using the Kaplan Meier method and log rank tests, respectively. Results: Between 1970 and 2010, 222 consecutive adult patients with NLPHL were identified. The median follow-up was 20 years. Of these, 17 (7.7%) developed a transformation to DLBCL during the course of the disease (Figure 1). The median time to transformation was 35 (6–248) months. Of these 17 patients, 13 (76.5%) were male, 11 (64.7%) had stage I/II and 6 (35.3%) had stage III/IV NLPHL. Transformation was the first relapse in most patients (12 patients, 70.6%) while five patients (29.4%) developed one or more relapses of NLPHL before transformation. Prior therapies for NLPHL were as follows: radiation therapy in 5 (29.4%), chemotherapy in 5 (29.4%) and combined chemotherapy and radiation in 6 (35.3%) patients. The median age at transformation was 45 years (30–87). Most patients (10 patients, 58.8%) presented with signs (palpable lymph nodes) or “B” symptoms. Eight patients (47.1%) had stage III/IV disease at the time of transformation. The most commonly used regimens for treatment of DLBCL were R-CHOP or CHOP (9 patients, 52.9%). Platinum based therapy was administered in 4 (23.5%) patients. Five patients (29.4%) required more than one line of therapy, and autologous stem cell transplant was utilized in two (11.7%) patients. Based on the observed 17 transformations during 2304 patient-years of follow-up, the rate of transformation was 0.74 per 100 patient-years. The five-year overall survival (OS) of patients with transformed disease (calculated from time of transformation) was 76.4%. The most common cause of death was lymphoma (75%). Following treatment for transformation, 5 patients (29.4%) relapsed. The OS in transformed patients was independent of prior therapies, and transformation did not adversely affect overall survival in our cohort (median survival of in 129 months in transformed versus 120 in non-transformed patients, P=0.33). In a univariate analysis of prior therapies, use of radiation therapy was associated with a significant delay in time to transformation (P= 0.0035) (Table 1, figure 2). Conclusions: The risk of transformation in NLPHL is 0.74% per year in this large single institution case series of NLPHL, and appears to be lower than that observed in follicular and other types of low grade lymphoma. The outcomes of patients with transformation were significantly better than reported in other types of transformed lymphoma and did not adversely affect OS. Disclosures: No relevant conflicts of interest to declare.