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Abstract BACKGROUND: Primary Mediastinal B-Cell Lymphoma (PMBL) is a rare form of B-cell non-Hodgkin lymphoma (Lones/Cairo et al, JCO 2000). We have previously reported a significant decrease in EFS among pediatric and adolescent patients with PMBL compared with other stage III non-PMBL diffuse large B-cell lymphoma (DLBCL) patients following FAB/LMB 96 therapy, suggesting that new therapeutic targeted agents are needed (Gerrard/Cairo et al, Blood 2013). Activation of the B-cell receptor (BCR) signaling pathway has now emerged as a central oncogenic pathway that promotes growth and survival in both normal and malignant B-cells. The cascade of signaling pathways downstream of the BCR includes BTK, MAPK, NF-κB and AKT. PMBL has a constitutively activated NF-kB pathway (Rosenwald et al, JEM 2003). Ibrutinib is a selective and covalent BTK inhibitor that inhibits chronic active BCR signaling and downstream signaling including the NF-kB pathway (Herman et al, Blood 2014) and is an active agent in ABC-DLBCL, which also has an activated NF-kB pathway (Griner et al, PNAS 2014). Preclinical studies of ibrutinib in CLL and MCL suggested that the inhibitory effects on cell proliferation were seen in the range of 1.0uM to 25.0uM (Herman et al, Blood 2011; Cinar et al, Leuk. Res 2013). Despite these relatively high IC50 values in vitro, ibrutinib has been highly effective in the treatment of patients with refractory CLL and MCL (Byrd et al, NEJM 2013 and Wang et al, NEJM 2013). Ibrutinib was approved by the FDA (IMBRUVICA, USPI) for patients with MCL in November 2013 or CLL in February 2014, who have received at least one prior therapy. However, the antitumor activity against PMBL of ibrutinib alone and in combination with other agents is currently unknown. OBJECTIVES: We hypothesize that ibrutinib in combination with other agents may be a future targeted agent in the treatment of PMBL. Therefore, we investigated the effect of ibrutinib alone and in combination with dexamethasone, rituximab and carfilzomib on cell proliferation and apoptosis in a PMBL cell line. METHODS: The Karpas-1106P PMBL cell line (DSMZ, Germany) was treated with ibrutinib alone (0-10uM, generously provided by Janssen R&D LLC) and in combination with dexamethasone (1uM), rituximab (20ug/ml) and carfilzomib (5nM) for 5 days treatment. The MTS cell proliferation assay (Promega) and western blot analysis were performed. Significant differences were determined by Student's t -test.The IC50 values were determined with CompuSyn software (Chou and Martin, ComboSyn, 2005). RESULTS: We observed a significant down-regulation of phosphorylated BTK after 5 days with ibrutinib treatment in Karpas-1106P cell line with 1uM ibrutinib (0.178 ± 1.63, p<0.0001) and the expression of total BTK protein was also significantly decreased with 1uM ibrutinib following 5 days of treatment (0.803±0.190, p<0.005) compared to control (1.000±0.00). We also observed a significant dose-dependent decrease in cell proliferation (0-10uM, p<0.0001) in ibrutinib-treated Karpas-1106P PMBL cell line. In combination with dexamethasone, the ibrutinib IC50 values for inhibition of cell proliferation were significantly decreased from 0.71uM ± 0.172 (ibrutinib alone) to 0.04uM ± 0.007 (p<0.005) with 1.0uM dexamethasone combination following 5 days of treatment. Second, in combination with rituximab experiment, the ibrutinib IC50 values was significantly decreased from 0.845uM ± 0.289 (ibrutinib alone) to 0.37uM ± 0.056 (p<0.05) with 20ug/ml rituximab following 5 days of treatment. Lastly, the ibrutinib IC50 values were significantly decreased from 0.72uM ± 0.185 (ibrutinib alone) to 0.002uM ± 0.001 (p<0.005) with 5nM carfilzomib combination following 5 days of treatment. CONCLUSIONS: Ibrutinib alone and in combination with dexamethasone, rituximab and carfilzomib significantly inhibited cell proliferation in the Karpas-1106P PMBL cell line. Ibrutinib's potential as an adjuvant agent in combination treatment in patients with PMBL is supported by these experiments. Future studies will focus on the in vivo effects of ibrutinib alone and in combination with dexamethasone and carfilzomib in a NOD/SCID PMBL xenograft mouse model. Disclosures Galardy: Mission Therapeutics: Research Funding.

Abstract Background We have previously reported on the significant, but heterogeneous baseline MPN symptom burden among an international sample of MPN patients (including essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)) utilizing the MPN Symptom Assessment Form (MPN-SAF) and the derivative Total Symptom Score (MPN-SAF TSS). Recent clinical trials have sought to determine optimal MPN symptom response criteria, such as absolute 10 point improvement in MPN SAF TSS for ET/PV (ELN Criteria, Barosi et. al. Blood 2013) and 50% reduction in MPN-SAF TSS for MF (IWG-MRT, Tefferi et. al. Blood 2013). We sought to determine the role of improvement in MPN-SAF TSS quartiles as potential thresholds to assess symptomatic response to therapy. Methods Utilizing prospectively gathered MPN-SAF TSS (Emanuel et. al. JCO 2012) in patients we assessed potential thresholds of response by evaluating quartile thresholds for severity of symptom burden. The MPN-SAF TSS was scored as the average of 10 symptoms (individual symptoms scores of 0-10, with a total score of 0 (best) to 100 (worst)). MPN-SAF TSS quartiles were identified by the percentage of scores between 0-24% (quartile 1 (Q1)), 25-49% (quartile 2 (Q2)), 50-74% (quartile 3 (Q3)), 75-100% (quartile 4 (Q4)). Results MPN-SAF TSS Quartiles: MPN-SAF TSS quartiles were identified among 1858 MPN patients (ET N=775, PV N=654, and MF N=423). Overall MPN-SAF TSS scores of 0 - 7 were designated as Q1, 8 - 17 as Q2, 18 - 31 as Q3, and ≥ 32 was as Q4. MPN-SAF TSS scores were significantly different between clusters (p<0.001). Associations Between Quartiles and Demographic/ Disease Factors: As quartiles increased, the proportion of PV and ET patients diminished and MF increased (Table 1, p<0.001). Cytopenias and transfusion dependence increased in prevalence in the higher quartiles (p<0.001). A history of prior thrombosis was also significantly more prevalent in the quartiles with highest symptom burden (p<0.001). The prevalence of women was significantly higher among the more symptomatic quartiles females 48.9% Q1, 49.4% Q2, 58.4% Q3, and 60.1% Q4; p<0.001). Associations Between Individual Symptoms and MPN-SAF TSS Quartiles: All individual symptoms measured in the MPN-SAF TSS were significantly worse in quartiles as they increased (p<0.0001). Evaluation of Prognostic Scoring and MPN-SAF TSS Quartiles: Comparison of each patients individual risk score (IPSET, PV, DIPSS for MF) and worsening symptom quartile showed the highest correlation with MF patients (DIPSS) (Table 1). However, ET and PV risk scores were not surrogates for symptom burden by quartile. Conclusions Distribution of MPN patient symptomatic burden by MPN-SAF TSS quartiles provides an easy-to-calculate method to cluster and analyze MPN patients of similar burden. Although MF patients are most prevalent in the most severe quartile of MPN symptomatology it is notable that Q4 has many patients with PV and ET. Future prospective efforts are ongoing to assess the potential of using changes in quartile (i.e. improving from Q3 to Q1) as potential symptomatic response thresholds. Disclosures: Etienne: novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Pfizer: Membership on an entity’s Board of Directors or advisory committees; Ariad: Membership on an entity’s Board of Directors or advisory committees. Roy:Novartis, BMS: Honoraria. Harrison:Gilead: Honoraria, Membership on an entity’s Board of Directors or advisory committees; S Bio: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Shire: Speakers Bureau; Celgene: Honoraria; YM Bioscience: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Vannucchi:Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Birgegard:Vifor Pharma: Honoraria.

Abstract Introduction Fedratinib (SAR302503), a JAK2-selective inhibitor, has demonstrated clinical improvements in splenomegaly and constitutional symptoms in patients with MF in Phase I/II trials (J Clin Oncol 2011;29:789. Haematologica 2013;98:S1113). The aim of this primary analysis was to determine the effect of fedratinib on key MF symptom burden and global assessment of HRQoL in the JAKARTA trial (NCT01437787). Methods JAKARTA is a double-blind, placebo-controlled, international, 3-arm, Phase III study, in which patients ≥18 years of age with intermediate- or high-risk MF, platelet count ≥50 × 109/L, and splenomegaly were randomized (1:1:1) to receive placebo or fedratinib at a dose of 400 or 500 mg, orally, once daily, in consecutive 4-week cycles. Total symptom score (TSS), a key efficacy end point (TSS: averaged daily total score of 6 item measures over 1 week: night sweats, pruritus, abdominal discomfort, early satiety, pain under ribs on left side, and bone or muscle pain), was assessed through a daily electronic eDiary using the modified Myelofibrosis Symptom Assessment Form (MFSAF; Cancer 2011;117:4869. Blood 2011;118:401), with symptom response defined as a ≥50% reduction in TSS at the end of Cycle 6 (EOC6). HRQoL was assessed using the EuroQOL (EQ)-5D instrument that was completed at baseline and EOC6. Patient performance was assessed using the Eastern Cooperative Oncology Group Performance Scale (ECOG PS). Spleen volume was measured by MRI or CT at baseline and EOC6. Results In JAKARTA, a total of 289 patients were randomized: median age 65 years; 59% male; 63% primary MF; 48% high-risk MF; 67% JAK2V617F positive; 16% platelet count <100 × 109/L. The symptom evaluable population comprised 261 patients (placebo [n=82]; 400 mg [n=89]; 500 mg [n=90]). The mean (SD) baseline TSS was 14.6 (11.9), 17.6, (13.5), and 16.9 (11.9) in the placebo, 400 mg, and 500 mg groups, respectively. At Week 24 (EOC6), the proportion of patients with a symptom response was significantly higher (p<0.0001) in the 400 and 500 mg groups versus placebo (Table). Symptom responses with fedratinib were also higher than placebo in the subgroup of patients with baseline platelets <100 × 109/L (Table). For individual symptoms, the greatest improvements were seen for night sweats and early satiety (Table). Baseline HRQoL (EQ-5D, mean [SD]) was similar in the three groups (placebo: 62.5 [21.2]; 400 mg: 61.3 [22.2]; 500 mg: 60.1 [20.1]). Fedratinib treatment led to improvements in HRQoL from baseline to Week 24, whereas placebo treatment led to slight worsening of HRQoL (Table). At Week 24, the degree of improvement in TSS was greatest in patients with ≥35% reduction in spleen volume from baseline (Figure). Mean TSS improvement was correlated with improvement in HRQoL (TSS reductions were greater in EQ-5D improvers versus non-improvers), and ECOG PS (TSS reductions were greater in patients with ECOG PS 1 or 2 score improvement versus those with ECOG PS worsening). Conclusions Fedratinib treatment over 24 weeks led to significant improvements in MF symptoms versus placebo. Patients treated with fedratinib also experienced substantial improvements in HRQoL versus placebo. Symptom improvements were associated with spleen responses. This study was sponsored by Sanofi. Disclosures: Mesa: Incyte, Genentech, Lilly, MS Pharma, Gilead: Research Funding. Cortes:Incyte, Sanofi: Consultancy; Incyte, Sanofi: Research Funding. Cervantes:Novartis: Speakers Bureau; Novartis and Sanofi: Membership on an entity’s Board of Directors or advisory committees. Jourdan:Sanofi: Honoraria. Vannucchi:Novartis: Membership on an entity’s Board of Directors or advisory committees. Drummond:TargeGen, Novartis: Speakers Bureau; Sanofi, Novartis, Celgene: Honoraria; Sanofi, Novartis, Celgene: Consultancy. Passamonti:Novartis, Celgene, Incyte, Sanofi, Roche: Honoraria. Neumann:Sanofi: Employment. Joulain:Sanofi: Employment. Iqbal:Sanofi: Employment. Harrison:Novartis: Research Funding; Novartis, Sanofi, YM Bioscience, Celgene, SBio, Gilead: Honoraria; Novartis, Sanofi, Shire: Speakers Bureau; Novartis, Sanofi, YM Bioscience, SBio, Gilead: Membership on an entity’s Board of Directors or advisory committees.

Abstract Background: Philadelphia chromosome negative myeloproliferative neoplasms (MPN) include myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET). Pertinent to these disorders is the high persistence, prevalence, and severity of fatigue. Overall, excessive fatigue compared to age and gender matched controls occurs in greater than 95% of MPN patients (Blood. 2011;118(2):401-8). Physiologic etiologies of fatigue in these patients include cytokine dysregulation and impaired hematopoiesis, however to date no one has investigated the impact that cofounding medical illnesses have on MPN fatigue burden. Methods: A 70-item internet-based survey was developed by a team of MPN investigators, patient advocates from MPN Forum, and hosted by the Mayo Clinic Survey Research Center. The survey was promoted online via multiple MPN-related webpages including the MPN Forum, MPN Net, MPN Research Foundation, and MPN Voice during late February to March of 2014. Surveyed data included disease demographics such as splenomegaly, thrombosis, hemorrhage transfusions, medications, and phlebotomies. The MPN-SAF (including the MPN 10) was utilized including the 10-item brief fatigue inventory was used to assess disease burden (Blood. 2011 Jul 14;118(2):401-8). Comorbid conditions were assessed, including hypothyroidism, anemias, sleep disturbances, obesity, and heart and lung disorders. Data: Demographics. Overall 1788 MPN patients participated in the survey. Of these, 1676 consented to participate and provided additional data (i.e., completed at least 10 questions). Of these, 555 (33%) patients had ET, 651 (39.0%) had PV, and 417 (25.0%) had MF. Among MF patients, 44.1% had primary MF, 29.7% had post-PV MF, and 26.2% had post-ET MF. Respondents were 68% female with a mean age of 59. Overall brief fatigue inventory score had a mean of 4.4 (range 0-10). MPN-10 score average was 28.4 (range 0-83). Medical Comorbidities. Overall, many patients endorsed having comorbid medical diseases that could contribute to overall fatigue (Table1). Overall 20.2% of patients endorsed having low thyroid function, with 10% indicating they obtained this diagnosis in the last six months. Twenty three percent endorsed having a new sleep disturbance in the last six months. On average, patients tended to have an average to above average BMI (mean =26.3, median = 25.0). However, many patients also experienced a high rate of unintended weight loss (11.8% with >11lb weight loss in the last 6 months). Cytopenias were also frequently encountered, with 14.7% of participants having required previous transfusions. Among these, 46% required transfusions in the last 6 months. Thrombosis (18.3%), hemorrhage (14.7%), and anemia (48.0%) were relatively common. In the last six months, 11.1% of patients required iron supplementation and 2.2% required erythropoietin injections. Many patients also endorsed the use of medications that could contribute to overall fatigue. Correlations. Items significantly correlated with worsened fatigue score (BFI greater than or equal to four) included female gender (<0.001), age (p=0.0047), lower education level (<0.001) and lower BMI (<0.001). Current use of alcohol and tobacco was also significantly associated with greater burden of fatigue (<0.001 and 0.0025, respectively). Items not significantly associated with fatigue included DIPSS (MF only), IPSET (ET only) or PV risk scoring. Conclusions Overall patients with MPN experience an exclusive pattern of disabling fatigue. Many fatigue-related medications and medical comorbidities may contribute to the debilitating fatigue seen among MPN patients, although no specific comorbidities could account for the high prevalence of fatigue. Rates of comorbid disease burden varied widely compared to the general population. For some diseases including diabetes, rates among MPN populations were less than the general population (National Diabetes Statistics Report, 2014), however the rates of other comorbidities, such as hypothyroidism, were higher (J Clin Endocrinol Metab 2002;87:489–99). Similar to our previous studies, females tended to suffer from a higher mean fatigue burden than males (Geyer ASH 2014). Clinical and research-related determination of fatigue should take into account cofounding comorbid medical conditions that can contribute to overall fatigue burden. Disclosures Harrison: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau; Shire: Speakers Bureau; CTI: Consultancy; YM Bioscience: Consultancy; Gilead: Consultancy; SBio: Consultancy. Mesa:Incyte: Research Funding; Novartis: Consultancy; Gilead: Research Funding; Genentech: Research Funding; Promedior: Research Funding; Ns Pharma: Research Funding; Celgene: Research Funding; Lilly: Research Funding; Cti: Research Funding.

Abstract Background Polycythemia vera (PV) is a clonal myeloproliferative disorder characterized by erythrocytosis, splenomegaly and a frequently burdensome symptom profile. Despite current guidelines of aspirin, phlebotomy, and selective cytoreduction, many patients have inadequately controlled PV-related symptoms and/or disease features. We performed a comparison of PV symptom burden/disease feature phenotypes to understand unmet needs in current medical management. Methods Data was collected prospectively amongst an international cohort of PV patients including symptom burden, demographics, and disease features. Subgroups were identified who had previously failed hydroxyurea (PV-HU), required ongoing phlebotomy (PV-P), had palpable splenomegaly (PV-S), or had all 3 features (PV-HUPS). Control groups were derived from the remaining PV patients lacking the specified subgroup trait; patients in whom the trait status was unknown were excluded from each respective control group. All participants completed the MPN specific symptom burden questionnaire (MPN-SAF TSS (MPN-10 – Table 1)) and had no prior history of splenectomy. Surveyed symptoms on the MPN-10 included the patient's perceptions of common MPN-related symptoms and overall quality of life (QOL) on a 0 (absent) to 10 (worst imaginable) scale. PV risk scores were calculated using the 2013 criteria (Leukemia 2013). Comparison of symptoms between groups employed t-tests. Results Patient Demographics and Disease Features Between Phenotypic Groups A total of 1334 PV patients completed the MPN-10, and were assigned to categories of PV-HU (499 [37%]), PV-P (646 [48%]), PV-S (369, [28%]), and PV-HUPS (148 [12%]). The demographics between these groups were similar (comparable age (median range 60-63), PV risk scores (mean risk range: Low 16.4-23.7%; Intermediate 31.4%-36.6%; High 42.8%-47%). Mean hemoglobin was similar among PV subgroups (range 14.4-14.9); PV-HUPS had a higher mean WBC count (20.3 g/dL vs. 8.8-11.8 g/dL) and platelet count (703.5 x 10(9)/L vs. 327.5-462.8 x 10(9)/L), and disease duration (11.5 years vs. 6.4-8.8 years). Prior thrombosis was most common in PV-S patients (28.5% vs. 21.8-25.2%) and prior hemorrhage was most common in PV-HUPS patients (23.8% vs. 13.7-15.8%). Symptom Burden The MPN-10 scores of each problematic PV phenotype (HU, P, S, HUPS) were compared to the remainder of the PV cohort lacking the trait (PV-control; Table 1). Both individual symptom scores and TSS were highest for PV-HUPS patients (mean TSS 32.5 vs. 27.7-29.2). All problematic PV subgroups demonstrated significant differences for individual symptoms and TSS compared to PV-control. Comparing "problematic" subgroup responses, PV-HU patients described more inactivity whereas PV-S patients described more early satiety and pruritus. No statistical differences were noted in PV-HU, PV-P and PV-HUPS patient responses to MPN-10 items of "fever" and "weight loss". Discussion PV patients who have either failed HU, are undergoing phlebotomy and/or have splenomegaly exhibit moderate to severe symptomatology and demonstrate unmet medical need for management. As evidenced in this study, considerable overlap in symptomatology exists in PV-HU, PV-P, PV-S and PV-HUPS. Current randomized trials of JAK inhibitors have demonstrated benefits in a PV-HUPS phenotype. This data suggests that PV patients with any evidence of inadequate control (PV-HU, P, or S) have similarly unmet needs and may be candidates for clinical trials, intensification of medical therapy or perhaps JAK inhibitor therapy. Disclosures Kiladjian: Shire Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Zweegman:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees, Research Funding. Besses:Shire Pharmaceuticals: honoraria for educational lectures Other. Birgegard:Shire Pharmaceuticals: Consultancy, Honoraria, Research Funding. Etienne:Novartis, BMS, Pfizer, Ariad: Honoraria. Roy:Merck: Peg-Interferon provided for academic clinical trial in CML Other. te Boekhorst:Novartis: Consultancy. Griesshammer:Novartis: Honoraria; Shire: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; Roche: Honoraria. Mesa:Incyte Corporation, CTI, NPS Pharma, Inc., Gilead Science Inc., Celgene: Research Funding.

Secretory carcinoma is a special-type breast carcinoma underpinned by a recurrent t(12;15)(p13;q25) translocation resulting in ETV6-NTRK3 gene fusion. Immunohistochemistry (IHC) using a pan-TRK antibody has been recently shown to help identify NTRK rearrangements in other tumor types. The purpose of this study was to assess the diagnostic utility of pan-TRK IHC in secretory carcinoma of the breast. Pan-TRK IHC was performed using a rabbit monoclonal antibody on whole sections of 24 breast secretory carcinomas and tissue microarray sections of other breast carcinoma types (n=203) and histologic mimics (n=15). Cases were assessed for staining intensity and localization. The 24 patients with secretory carcinoma had a median age of 44 years and a median tumor size of 1.0 cm. ETV6 fluorescence in situ hybridization was positive in all cases tested (n=20). Twenty-three cases (95.8%) showed staining with pan-TRK, which was exclusively nuclear in 19, primarily nuclear with weak cytoplasmic staining in 3, and primarily cytoplasmic with focal nuclear staining in 1. The nuclear staining was diffuse in 17 and at least focally strong in 17. The only pan-TRK negative case was a core biopsy with limited tumor. Among the 203 nonsecretory carcinomas, 21 (10.3%) showed focal, weak nuclear staining in <5% of tumor cells and 1 (0.5%) showed focal membranous staining. All histologic mimics were negative. In conclusion, diffuse and/or at least focally strong nuclear pan-TRK staining is a sensitive and specific marker for secretory carcinoma of the breast.

Significance Statement The lack of rapidly progressive murine models reflecting the more severe end of the spectrum of autosomal recessive polycystic kidney disease (ARPKD) inhibits progress to understanding ARPKD pathogenesis. Defects in primary cilia have been implicated in polycystic kidney disease, but their potential role is poorly understood. The authors generated and characterized new mouse and rat models of ARPKD and autosomal dominant polycystic kidney disease (ADPKD) and investigated the interaction between causative genes for these two conditions. Their digenic models demonstrated a synergistic interaction that better reflects the early-onset disease characteristic of ARPKD. Analysis of mRNA expression in the models highlighted different disrupted pathways, but with a commonality of dysregulated mechanisms associated with primary cilia. These models may improve understanding of ARPKD and preclinical testing for this disease. Background Autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic kidney disease (ADPKD) are genetically distinct, with ADPKD usually caused by the genes PKD1 or PKD2 (encoding polycystin-1 and polycystin-2, respectively) and ARPKD caused by PKHD1 (encoding fibrocystin/polyductin [FPC]). Primary cilia have been considered central to PKD pathogenesis due to protein localization and common cystic phenotypes in syndromic ciliopathies, but their relevance is questioned in the simple PKDs. ARPKD’s mild phenotype in murine models versus in humans has hampered investigating its pathogenesis. Methods To study the interaction between Pkhd1 and Pkd1 , including dosage effects on the phenotype, we generated digenic mouse and rat models and characterized and compared digenic, monogenic, and wild-type phenotypes. Results The genetic interaction was synergistic in both species, with digenic animals exhibiting phenotypes of rapidly progressive PKD and early lethality resembling classic ARPKD. Genetic interaction between Pkhd1 and Pkd1 depended on dosage in the digenic murine models, with no significant enhancement of the monogenic phenotype until a threshold of reduced expression at the second locus was breached. Pkhd1 loss did not alter expression, maturation, or localization of the ADPKD polycystin proteins, with no interaction detected between the ARPKD FPC protein and polycystins. RNA-seq analysis in the digenic and monogenic mouse models highlighted the ciliary compartment as a common dysregulated target, with enhanced ciliary expression and length changes in the digenic models. Conclusions These data indicate that FPC and the polycystins work independently, with separate disease-causing thresholds; however, a combined protein threshold triggers the synergistic, cystogenic response because of enhanced dysregulation of primary cilia. These insights into pathogenesis highlight possible common therapeutic targets.

AbstractPurpose/Objective(s)Bladder and prostate are unfavorable sites for rhabdomyosarcoma (B/P‐RMS), and represent a challenging location for radiotherapy.Materials/MethodsNineteen patients with B/P‐RMS were enrolled on a prospective registry protocol (2008‐2017) and treated with chemotherapy, proton beam therapy (PBT), and surgical resection (n = 8; 42%). Emphasis was given to treatment technique, disease‐related outcomes, and toxicity associated with PBT.ResultsThe majority of patients had bladder RMS (74%) of embryonal histology (95%), Group III (68%), and intermediate‐risk disease by Children's Oncology Group (COG) risk stratification (89%). Seven patients (37%) had primary tumors >5 cm in size. All patients were treated according to COG protocols. With a median follow‐up of 66.2 months, 5‐year overall survival (OS) and progression‐free survival (PFS) were 76%. Four patients (21%) experienced disease relapse, all presenting with local failure. The 5‐year local control (LC) rate was 76%. Tumor size predicted LC, with 5‐year LC for patients with >5 cm tumors being 43% versus 100% for those with ≤5 cm tumors (P = .006). Univariate analysis demonstrated an effect of tumor size on OS (tumor >5 cm, hazard ratio [HR] 17.7, P = .049) and PFS (HR 17.7, P = .049). Acute grade 2 toxicity was observed in two patients (11%, transient proctitis). Late grade 2+ toxicity was observed in three patients (16%; n = 1 grade 2 skeletal deformity; n = 3 transient grade 2 urinary incontinence; one patient experienced both).ConclusionsPBT for B/P‐RMS affords promising disease‐related outcomes with an acceptable toxicity profile. Higher local failure rates were observed for larger tumors, supporting dose‐escalation components of ongoing RMS clinical trials.

Abstract Background: Smoking has been associated with colorectal cancer (CRC) risk; but limited evidence has shown the association between smoking and molecular subtypes of CRC. Methods: We analyzed 9,422 CRC cases and 9,950 controls from 10 observational studies. Multinomial logistic regression analysis was performed to assess the association between sex-study-specific quartiles of pack years of smoking and risk of CRC molecular subtypes, using non-smokers as reference group, adjusting for age, sex, and study. Known oncogenic mutations in four somatic colorectal tumor markers were assessed individually and in combination, including BRAF mutations, KRAS mutations, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status. Case-only analysis was also performed to estimate heterogeneity in risk of molecular subtypes of CRC. Results: Compared with controls, higher pack years of smoking were statistically significantly associated with increased CRC risk when stratified, individually, by all four markers, and the associations got stronger with higher quartiles pack years (p-trend&lt;0.001). Associations between smoking and CRC risk also differed significantly among molecular subtypes. Compared to nonsmokers, the risk of BRAFmut CRC was 83% higher for smokers within the highest quartile of pack-years (OR=1.83; 95% CI: 1.50, 2.25), and 29% higher for BRAFwt CRC (OR=1.29; 95% CI: 1.17, 1.43; Ratio of ORs (ROR)=1.45; 95% CI: 1.18, 1.17; p=3.45x10-4). Similarly, heavy pack-years of smoking was associated with almost two times higher risk of CIMP-high CRC (OR=1.93; 95% CI: 1.60, 2.31), but only 33% higher risk of CIMP-low/negative CRC (OR=1.33; 95% CI: 1.19, 1.48; ROR=1.49; 95% CI: 1.24, 1.79; p=1.72x10-5). The association between smoking and CRC was also stronger in MSI-high tumors (ORMSI-H=1.65; 95% CI: 1.36, 2.00; ORMSI-L/MSS=1.37; 95% CI: 1.23, 1.52; ROR=1.22; 95% CI: 1.00, 1.48; p=0.046). In contrast, the association between smoking and CRC risk was stronger for KRASwt (OR=1.43; 95% CI: 1.27, 1.60), than KRASmut tumors (OR=1.18; 95% CI: 1.02, 1.37; ROR=0.83; 95% CI: 0.71, 0.97; p =0.016). When combining tumor markers, smoking was found to be significantly associated with higher risk of colorectal tumors from the serrated pathway. Conclusion: In this largest study with a total of 19,372 subjects, we found that heavier pack years of smoking was associated with increased risk of all CRC molecular subtypes. Smokers with heavier pack-years of smoking had particularly higher risk of CRC subtypes with BRAF mutation and CIMP-high, suggesting smoking may be particularly involved in the development of these subtypes of colorectal tumor. Citation Format: Xiaoliang Wang, Efrat Amitay, Barbara L. Banbury, Hermann Brenner, Daniel D. Buchanan, Peter T. Campbell, Jenny Chang-Claude, Steven J. Gallinger, Graham G. Giles, Tabitha A. Harrison, John L. Hopper, Mark A. Jenkins, Yi Lin, Reiko Nishihara, Polly A. Newcomb, Shuji Ogino, Lori C. Sakoda, Robert E. Schoen, Martha L. Slattery, Steven N. Thibodeau, Bethany Van Guelpen, Michael O. Woods, Li Hsu, Michael Hoffmeister, Ulrike Peters. Smoking is associated with risks of molecular subtypes of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 630.