Chaffee, Kari G.

Monocyte‐derived cells, constituents of the cancer microenvironment, support chronic lymphocytic leukemia (CLL) cell survival in vitro via direct cell‐cell interaction and secreted factors. We hypothesized that circulating absolute monocyte count (AMC) reflects the monocyte‐derived cells in the microenvironment, and that higher AMC is associated with increased CLL cell survival in vivo and thus inferior CLL patient outcomes. We assessed the extent to which AMC at diagnosis of CLL is correlated with clinical outcomes, and whether this information adds to currently used prognostic markers. We evaluated AMC, clinically used prognostic markers, and time to event data from 1,168 CLL patients followed at the Mayo Clinic, the Duke University Medical Center, and the Durham VA Medical Center. Elevated AMC was significantly associated with inferior clinical outcomes, including time to first therapy (TTT) and overall survival (OS). AMC combined with established clinical and molecular prognostic markers significantly improved risk‐stratification of CLL patients for TTT. As an elevated AMC at diagnosis is associated with accelerated disease progression, and monocyte‐derived cells in the CLL microenvironment promote CLL cell survival and proliferation, these findings suggest that monocytes and monocyte‐derived cells are rational therapeutic targets in CLL. Am. J. Hematol. 91:687–691, 2016. © 2016 Wiley Periodicals, Inc.

The impact of race on outcomes of patients with chronic lymphocytic leukemia (CLL), the most common leukemia in the west, is not well studied. We aimed to understand racial variations in clinical and disease characteristics, treatment patterns, and outcomes in patients with CLL. We utilized the Mayo Clinic CLL database to perform an analysis of these characteristics and natural history of non‐white (NW) compared to white (W) CLL patients. Differences by race in median overall survival (OS) and time‐to‐first‐treatment (TTFT) were investigated. Of the 4215 CLL patients, 4114 (97.6%) were W and 101 (2.4%) were NW. NW patients were younger (median age at diagnosis 59.4 vs. 63.4; P = 0.003) and more likely to have an elevated LDH (28.0% vs. 16.2%; P = 0.02). No differences in prognostic parameters were noted. No major differences were observed in treatment selection. OS and TTFT were similar between both groups. In the largest analysis of NW‐CLL patients in North America, and contrary to historical retrospective reports, W and NW patients appear to have comparable outcomes when treated similarly. These findings suggest previously noted outcome differences may be due to disparities in access to care and management rather than differences in disease biology. Am. J. Hematol. 91:677–680, 2016. © 2016 Wiley Periodicals, Inc.

Abstract Pancreatic cancer is projected to become the second leading cause of cancer-related death in the United States by 2020. A familial aggregation of pancreatic cancer has been established, but the cause of this aggregation in most families is unknown. To determine the genetic basis of susceptibility in these families, we sequenced the germline genomes of 638 patients with familial pancreatic cancer and the tumor exomes of 39 familial pancreatic adenocarcinomas. Our analyses support the role of previously identified familial pancreatic cancer susceptibility genes such as BRCA2, CDKN2A, and ATM, and identify novel candidate genes harboring rare, deleterious germline variants for further characterization. We also show how somatic point mutations that occur during hematopoiesis can affect the interpretation of genome-wide studies of hereditary traits. Our observations have important implications for the etiology of pancreatic cancer and for the identification of susceptibility genes in other common cancer types. Significance: The genetic basis of disease susceptibility in the majority of patients with familial pancreatic cancer is unknown. We whole genome sequenced 638 patients with familial pancreatic cancer and demonstrate that the genetic underpinning of inherited pancreatic cancer is highly heterogeneous. This has significant implications for the management of patients with familial pancreatic cancer. Cancer Discov; 6(2); 166–75. ©2015 AACR. This article is highlighted in the In This Issue feature, p. 109

Abstract Background: Epidemiologic studies have suggested that metformin use is associated with cancer death reduction. The results for pancreatic ductal adenocarcinoma (PDAC) are inconsistent. Retrospective studies of cancer survival may potentially have unintended biases; due to complexities of diabetes management, metformin use exposure is commonly categorized as simply “yes/no.” Nevertheless, in part based on epidemiologic studies, there are at least 20 open cancer clinical trials that include metformin in a treatment arm. We aimed to study metformin use and survival of patients with PDAC, addressing potential inherent biases. Methods: A retrospective cohort study for the years 2000-2011 was conducted using the patient database of the Mayo Clinic Specialized Programs of Research Excellence (SPORE) in Pancreatic Cancer. 1,360 PDAC patients (59% male; mean age 67) with diabetes were studied; overall survival was the primary outcome. Initiation and duration of metformin use was carefully abstracted from medical records. Patients were categorized into 5 groups based on metformin initiation: (A) Never used, n = 908 (reference group); (B) Metformin started >1 year prior to PDAC diagnosis, n = 84; (C) Metformin started within 1 year prior to PDAC diagnosis, n = 212; (D) Metformin started <30 days post-PDAC diagnosis, n = 104; (E) Metformin started >30 days post PDAC diagnosis, n = 34. Hazard ratios (HR) and 95% confidence intervals (C.I.) for survival differences between groups were computed using Cox proportional hazards models, adjusting for age, sex, disease stage, body mass index, and diagnosis year group. Results: Median survival of patients in Groups B-E was 292 days compared to 308 for Group A; this was not significantly different. However, among 413 resectable patients, metformin users appeared to survive longer than non-users (782 vs. 612 days, p = 0.07). Survival in each group was 308, 245, 249, 243 and 818 days, respectively. Because Group E had already survived >30 days, a bias existed. With Group E excluded, there was no survival difference among the other 4 groups (p = 0.18). Compared to Group A, HR and 95% C.I. for metformin use were 1.08 (0.85-1.37), 0.99 (0.85-1.17), 1.04 (0.83-1.31) and 0.49 (0.33-0.74), for Group B-E, respectively. Conclusions: Our thorough analysis suggests that metformin use does not improve survival of patients with PDAC. The benefit of metformin was observed only in patients who started metformin post-PDAC diagnosis; however, there is an inherent survival bias in this group of patients. Studies of medication exposure and cancer survival warrant very careful and detailed data collection. Researchers should exercise caution when initiating clinical trials based on retrospective epidemiologic studies. Citation Format: Roongruedee Chaiteerakij, David B. Zhen, Patrick A. Burch, Kari G. Chaffee, William R. Bamlet, Ann L. Oberg, Lewis R. Roberts, Gloria M. Petersen. Metformin use does not increase survival of pancreatic cancer patients: A cautionary lesson. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-183. doi:10.1158/1538-7445.AM2015-LB-183

Abstract Introduction Chronic lymphocytic leukemia (CLL) is a B-cell malignancy that is known to have a familial component to disease risk. Although 31 loci have been found to be associated with CLL risk, the functional variant(s) driving these associations is mostly unknown. Here we set out to identify rare, highly-penetrant, cosegregating, susceptibility variants within the known GWAS discovered loci using whole exome sequencing (WES) data in CLL families from the Mayo Clinic family study of B-cell malignancies. Methods We performed WES on germ line DNA of 93 CLL families with two or more members with CLL, using Agilent capture kits and Illumina HiSeq2000. Bioinformatics analyses leveraged the following software packages: Novoalign, Picard, The Genome Analysis Toolkit (GATK), and the Biological Reference Repository (bioR). Quality control filters were implemented; subjects with mis-specified relationships were removed, as were variants with <75% call rate, <8X coverage, and those identified as sequencing artifacts. Each GWAS locus was defined by +/- 1Mb of the top GWAS hit within the locus. Linkage disequilibrium (LD) was calculated among the single nucleotide variants (SNVs) located within each locus. Potentially functional SNVs were identified based on: a) uncommon in public databases (< 5%), b) cosegregating in at least two CLL families, c) being highly conserved and in coding regions, and d) functional prediction status of deleterious (SIFT Score), damaging (PolyPhen Score), and a moderate, or high variant impact (SNP Effect). Results In our 93 CLL families, we sequenced 443 individuals: 160 with CLL, 73 with monoclonal B cell lymphocytosis (MBL), and 210 relatives that were not diagnosed with CLL or MBL at the time of sequencing. Median age of CLL diagnosis was 59 years (range 34-87), and 56% were male. Among the MBL individuals and relatives, the median age at recruitment was 55 years (range 18-93), and 40% were male. A total of 317,666 SNVs passed our sequencing quality control filters of which 10,731 were within +/- 1 Mb of known GWAS hits from 31 loci. Of these SNVs, 91% were in coding regions, 18% were reported to have high or moderate impact, 6% were estimated to be damaging and 6% were predicted to be deleterious. From these SNVs, we identified 76 putatively functional variants distributed across 25 GWAS loci that were cosegregating in the individuals with CLL or MBL in multiple CLL pedigrees. These SNVs were all located in coding regions with high or moderate impact and were predicted to be damaging and deleterious. Of these 76 variants, 56 had a frequency of <0.005 in 1000 Genomes’ European population while the remaining 20 had a frequency of 1%. Conclusions Through WES, we identified a number of rare, penetrant and potentially predisposing SNVs located within 25 of the 31 CLL GWAS-discovered loci. These segregating variants provide a list for future validation and functional studies. Citation Format: Sara Beiggi, Daniel R. O'Brien, Sara J. Achenbach, Kari G. Chaffee, Timothy G. Call, Neil E. Kay, Tait D. Shanafelt, Julie Cunningham, James R. Cerhan, Celine M. Vachon, Susan L. Slager. Cosegregating variants in chronic lymphocytic leukemia (CLL) families that are located in loci discovered by genome wide association studies (GWAS). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2764. doi:10.1158/1538-7445.AM2015-2764

Although ibrutinib and idelalisib are profound treatment advances, they will dramatically increase individual out-of-pocket and societal costs of caring for patients with CLL.

BACKGROUND Although hypogammaglobulinemia is a well recognized complication in patients with chronic lymphocytic leukemia (CLL), its prevalence at the time of CLL diagnosis, and association with novel prognostic markers and clinical outcome is not well understood. METHODS All patients at the Mayo Clinic between January 1999 and July 2013 who had newly diagnosed CLL and had a baseline assessment of serum immunoglobulin G (IgG) were included. The relation between hypogammaglobulinemia at diagnosis and the novel prognostic parameters time to first treatment (TFT) and overall survival (OS) were evaluated. RESULTS Of 1485 patients who met the eligibility criteria, 382 (26%) had hypogammaglobulinemia (median IgG, 624 mg/dL), whereas the remaining 1103 patients (74%) had normal serum IgG levels (median IgG, 1040 mg/dL). Patients who had hypogammaglobulinemia at diagnosis were more likely to have advanced Rai stage (III‐IV; P = .001) and higher expression of CD49d ( P < .001) compared with patients who had normal IgG levels. Although the median TFT for patients who had hypogammaglobulinemia was shorter compared with that for patients who had normal IgG levels (3.8 years vs 7.4 years; P < .001), on multivariable analysis, there was no difference in OS between these 2 groups (12.8 years vs 11.3 years, respectively; P = .73). Of 1103 patients who had CLL with normal IgG levels at diagnosis and who did not receive CLL therapy, the risk of acquired hypogammaglobulinemia was 11% at 5 years and 23% at 10 years. CONCLUSIONS Hypogammaglobulinemia is present in 25% of patients with newly diagnosed CLL. Approximately 25% of patients who have CLL with normal IgG levels at diagnosis will subsequently develop hypogammaglobulinemia on long‐term follow‐up. The presence of hypogammaglobulinemia does not appear to impact overall survival. Cancer 2015;121:2883–2891. © 2015 American Cancer Society .

Although transformation to Hodgkin lymphoma (HL) is a recognized complication in patients with chronic lymphocytic leukemia (CLL), its incidence, clinical characteristics and outcomes are not well defined. We used the Mayo Clinic CLL and Lymphoma Databases to identify CLL patients who developed biopsy‐proven HL (CLL/HL) on follow‐up, as well as cases of de novo HL (i.e., without prior CLL). Among 3887 CLL patients seen at Mayo Clinic from January 1995 through August 2011, 26 (0.7%) developed HL. In a nested cohort of 2,465 newly diagnosed CLL patients followed prospectively, the incidence of HL was 0.05%/year (10 year risk = 0.5%). The median overall survival (OS) from date of HL diagnosis in patients with CLL/HL was 3.9 years compared to not reached for de novo HL patients ( n = 709) seen during the same time interval ( P < 0.001). The shorter OS of CLL/HL patients persisted after adjusting for differences in age and Ann Arbor stage of disease. The International Prognostic score (IPS) developed for de novo HL stratified prognosis among CLL/HL patients with median survival of not reached, 6.2, 2.4, and 0.3 years ( P = 0.006) for those with IPS scores of ≤2, 3, 4, and ≥5, respectively. In summary, approximately 1 of every 200 CLL patients will develop HL within 10 years. Survival after HL diagnosis in patients with CLL is shorter than de novo HL patients. The IPS for de novo HL may be useful for stratifying survival in CLL/HL patients. Am. J. Hematol. 90:334–338, 2015. © 2015 Wiley Periodicals, Inc.

Key Points Deep sequencing identifies a significant reservoir of subclonal mutations affecting key genes in CLL pathogenesis. Convergent evolution of genetic lesions in tumor subclonal populations is recurrently found in CLL.