Indolent Phenotype Research Articles

Molecular Profiling and the Impact of Treatment on Outcomes in Adenoid Cystic Carcinoma Type I and II.

Adenoid cystic carcinoma (ACC) is an uncommon salivary gland cancer with no approved therapies available to treat advanced, incurable disease. Recent molecular profiling efforts have identified two important subtypes: the more aggressive ACC-I is characterized by Notch pathway alterations and MYC amplification whereas ACC-II demonstrates a more indolent phenotype and TP63 overexpression. This retrospective observational cohort study involved de-identified samples from 438 patients with ACC with tumor samples sent for commercially-available molecular profiling (Caris Life Sciences). Next-generation whole-exome and whole-transcriptomic sequencing was performed on primary and metastatic samples. Immunostaining for PD-L1 and RNA deconvolution (quanTIseq) was used to explore the tumor immune microenvironment (TME). Real-world clinical and survival outcome metrics were extracted from insurance claims data. MYC expression was 1.61-fold higher (39.8 vs. 24.7; P < 0.0001) among NOTCH1-mutant ACC-I tumors, whereas MYB/L1 fusion rates were similar among ACC-I/II. The median B-cell fraction in the TME was higher among ACC-II (7.1% vs. 5.8%; P < 0.01), although infiltrating T cells subsets were low among either ACC subgroup (both <1%). When pooling systemic treatment categories, ACC-I patients had worse outcomes with available therapies (HR, 3.06; 95% confidence interval, 1.65-5.68; P < 0.01), with no significant difference in overall survival between ACC-I/II based on chemotherapy or VEGFR tyrosine kinase inhibitor exposure in smaller subsets. We confirmed the previously reported associations with MYC and TP63 in the prognostically relevant subgroups of ACC-I and -II, respectively, and report immunologic differences among these subtypes. Survival outcomes are comparatively worse in ACC-I regardless of treatment type.

Clinicopathological and treatment response characteristics of updated rhabdomyosarcoma histomolecular subtypes: An Asian population-based study.

New histomolecular subtypes of rhabdomyosarcoma have recently been defined but their corresponding clinical characteristics are not well described. Also, these clinical phenotypes vary greatly by age and ethnicity but have not been profiled in Asian populations. Thus, we sought to determine the landscape of rhabdomyosarcoma subtypes in a national Asian cohort and compare clinical characteristics among age groups and molecular subtypes. We performed a retrospective population-based study of all rhabdomyosarcoma patients in Singapore public hospitals from 2004 to 2014 (n=67), and assigned histomolecular subtypes according to the updated 2020 WHO classification of soft tissue tumors following central pathology review and molecular profiling. Age-specific prevalence followed a tri-modal peak. There were significantly more embryonal and alveolar (p=0.032) and genitourinary (non-bladder/prostate) tumors (p=0.033) among children. Older age was associated with complete resection among spindle cell/sclerosing tumors (p=0.027), with the omission of chemotherapy among embryonal tumors (p=0.001), and with poorer survival among embryonal and alveolar tumors (p=0.026, p=0.022, respectively). Overall survival differed with stage, group, and surgical resection, adjusted for age group (p=0.004, p=0.001, p=0.004, respectively). Spindle-cell/sclerosing tumors showed an indolent phenotype with a significantly lower incidence of nodal metastasis (p=0.002), but two of 15 patients with MYOD1 mutations had a contrastingly aggressive disease. Disease and treatment response profiles of rhabdomyosarcoma subtypes vary significantly between adults and children, especially surgical resectability. In our Asian population, poorer outcomes were observed in adults with embryonal and alveolar tumors, while activating mutations influence the behavior of otherwise favorable spindle cell/sclerosing tumors.

Essential Thrombocythemia in Adolescents and Young Adults: Clinical Aspects, Treatment Options and Unmet Medical Needs.

Current treatment of essential thrombocythemia (ET) should primarily prevent thrombo-hemorrhagic events, without increasing the rate of fibrotic progression or leukemic evolution, and secondarily control microvascular symptoms. Unlike other classic BCR::ABL1-negative myeloproliferative neoplasms, ET is frequently diagnosed in adolescents and young adults (AYA), defined as individuals aged 15 to 39years, in up to 20% of patients. However, since the current risk stratification of this disease is based on models, including that of ELN, IPSET-Thrombosis and its revised version, mainly applied to an older patients' population, international guidelines are needed that specifically consider how to evaluate the prognosis of AYAs with ET. Furthermore, although ET is the most frequent MPN among AYA subjects, there is a lack of specific recommendations on how to treat it in this subgroup of patients, as management decisions are typically extrapolated from those for the elderly. Accordingly, since AYAs with ET represent a unique disease subset defined by attenuated genetic risk, more indolent phenotype, and longer survival than their older counterparts, treatment selection requires special attention to specific issues such as the risk of fibrotic/leukemic transformation, carcinogenicity, and fertility. This review article will provide a comprehensive overview of the diagnosis, prognostic stratification, and possible therapeutic approaches for AYA patients with ET, including antiplatelets/anticoagulants and cytoreductive agents, with a focus on pregnancy management in real-life clinical practice.

Abstract 133: Rewinding the tape of life: somatic profiling in Von Hippel-Lindau (VHL) disease reveals evolutionary contingency and constraints

Abstract Whether cancer evolution follows a deterministic route prescribed by host factors (germline genetics and/or environment) or proceeds along multiple alternative trajectories due to the stochastic nature of evolution is unknown. Patients with VHL disease have a pathogenic germline mutation in VHL (3p25) and tumorigenesis occurs when the wild-type copy of VHL is lost. Patients develop multiple clonally independent tumors including clear cell renal cell carcinoma (ccRCC), pheochromocytoma or paraganglioma (PPGL) and pancreatic neuroendocrine tumors (pNET), offering an opportunity to test repeatability of evolutionary trajectories between and within patients. We performed deep targeted exome sequencing, in 1520 tumors (993 solid ccRCC; 156 cystic ccRCC; 135 mixed solid/cystic ccRCC; 236 extra-renal) from 130 patients with VHL disease to evaluate somatic variants and copy number alterations, ploidy and chromosomal complexity. Tumor phenotype was evaluated from pathology reports and longitudinal growth kinetics from diagnostic MRI data. Analysis of 889 tumor samples is complete and profiling of the full cohort will be presented at the 2023 AACR meeting. Within clonally independent tumors, we performed two tests to assess for evidence of convergence between tumors from the same patient. First, we tested for parallel events in canonical ccRCC drivers. We found significant enrichment of somatic VHL variants occurring in one patient with a germline whole VHL gene deletion encompassing neighboring BRK1. Contiguous BRK1 loss is associated with less aggressive ccRCC phenotype and our findings suggest a specific constraint in this patient. We next assessed for evidence of convergence by measuring the genetic distance of copy number and mutational profiles between and within patients with resampling and permutation. Similar somatic profiles between tumors were only detected in 1/76 patients whose tumors were characterized by infrequent somatic alterations beyond 3p loss indicating little evidence of convergence. Cystic ccRCCs represent an indolent phenotype not associated with metastasis that may progress to solid tumors over time; we found mixed tumors closely resemble somatic profiles of solid tumors whereas cysts were characterized by infrequent copy number gains and low chromosomal complexity. We also identified cysts with specific losses (chr16, chr17, chr19p) mutually exclusive with 3p LOH suggestive of VHL-loss independent cyst formation. In solid ccRCCs, we found chromosomal complexity and loss of specific chromosomal loci (9p and/or 14q) are associated with diameter potentially reconciling the observation linking risk of metastasis to tumor diameter in VHL-related ccRCC. In summary, within the constrained setting of VHL-related ccRCC, evolution is dominated by chance although specific patient and phenotype specific constraints are observed. Citation Format: Scott T. Shepherd, Alex Coulton, Cathy D. Vocke, Chris J. Ricketts, Mark Ball, Fiona Byrne, Yuliia Dovga, Annika Fendler, Barber Taja, Olga O'Neill, Lina Gerontogianni, Gavin Kelly, Laura S. Schmidt, Daniel R. Crooks, Kirstin Choo, Rabindra Gautam, Zoe Blake, Krista Reynolds, Kevin Litchfield, Maria Merino, Marston W. Linehan, Samra Turajlic. Rewinding the tape of life: somatic profiling in Von Hippel-Lindau (VHL) disease reveals evolutionary contingency and constraints [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 133.

Abstract 2289: Comprehensive multiomic analysis reveals different subtypes in neuroendocrine tumors from multiple origins

Abstract Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors with a wide anatomical distribution and different clinical behaviors that share common “neuro” and “endocrine” properties. They are classified in well differentiated G1, G2 and G3 neuroendocrine tumors (NETs), or poorly differentiated neuroendocrine carcinomas (NECs) which are all G3. Some studies have assessed the NET molecular landscape of certain primary sites, but no cross-sites molecular assessment has been performed to date. Thus, we aimed to perform a comprehensive transcriptomic and methylomic characterization of large series of NENs of different anatomical origins in order to identify molecular subgroups, unravel genes and/or pathways involved, and explore their potential clinical relevance. Transcriptomic and methylation data were obtained from tumor samples of 181 and 99 patients with NENs (37.02%G1; 54.7%G2 and 8.29%G3) using Clariom S Human microarrays and EPIC methylation arrays, respectively. Most common primary tumor site was the lung (43.1%), followed by the small intestine (35.4%), large intestine (8.8%), stomach (4.4%), pancreas (1.7%), other localizations (3.9%), and unknown primary (2.8%). Tumors were clustered using transcriptomic and methylation data by NMF and hierarchical clustering algorithms respectively, and differential expression (limma analysis) and gene set enrichment analysis (GSEA) was applied to transcriptomic data clusters NENs were classified into three different clusters. Two of them (C1 and C3) showed an inverse transcriptomic profile, while C2 presented a mixed profile. We identified that C3 had the highest expression levels of neuroendocrine-related genes (somatostatin receptor SSTR5 LFC: 0.77 ; FDR: 1.52x10e-25 ; serotonin receptor HTR1A LFC: 0.79 ; FDR: 1.20X10e-20 ; VIP LFC: 0.64 ; FDR= 1.41x10e-10 etc), in lung primary tumor samples (50%) and methylation cluster 1 (82.14%). On the other hand, C1 was enriched in some important cancer-related pathways ( MYC targets NES -6.37 FDR &amp;lt; 10-3; MTORC1 NES -3.78 FDR &amp;lt; 10-3) and oxidative phosphorylation (NES -4.87 FDR &amp;lt; 10-3) ; and showed a higher proportion of small intestine primary tumors (46.34%), Grade 2 tumors (73.17%) and methylation cluster 2 (75%). NENs of different primary sites can be stratified into two major transcriptomic clusters, with a third cluster having a mixed expression profile. The groups with extreme transcriptomic signatures were enriched in neuroendocrine-related genes or principal cancer pathways. These results suggest a dedifferentiation from a more indolent neuroendocrine phenotype to more aggressive proliferative tumor types that could be driven partially with the methylation profile. Citation Format: Carlos Carretero Puche, Beatriz Soldevilla, Beatriz Gil, Anna La Salvia, Alberto Lens-Pardo, Paula Espinosa, Beatriz Anton-Pascual, Gonzalo Gómez-López, Fátima Al-Shahrour, Rocío García-Carbonero. Comprehensive multiomic analysis reveals different subtypes in neuroendocrine tumors from multiple origins [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2289.

CD24/Siglec-10 “Don't Eat Me” Signal Blockade Is a Potential Immunotherapeutic Target in Mantle-Cell Lymphoma

IntroductionMantle-cell lymphoma (MCL) is a B-cell non-Hodgkin Lymphoma (NHL) characterized by heterogenous behavior, ranging from indolent phenotype to highly aggressive and drug resistant one with dismal prognosis. Drug resistance may be generated by Tumor Microenvironment (TME), owing that Tumor-Associated Macrophages (TAM) are pathologically functional in providing survival signals to MCL cells (Pham, Front Oncol. 2018).Recently, “Don't Eat Me” signal (DEMs) blockade with anti-CD47 monoclonal Antibody (moAb) showed promising activity in pretreated NHL, through increase of phagocytosis by TAM (Advani, NEJM. 2019).CD24 was also demonstrated to be involved in DEMs and, in a preclinical model of solid cancer, blocking the CD24/Siglec-10 interaction provided an improvement of M2-like TAM-mediated phagocytosis in vitro and an increase of survival in vivo (Barkal, Nature. 2019).CD24 can be expressed in some phases of B-cell differentiation and MCL derives from a B-cell precursor with upregulated CD24. To date, there are no functional studies showing an improvement of phagocytosis through CD24/Siglec-10 pathway inhibition in hematologic malignancies and MCL.Here, we present our in vitro results of CD24/Siglec-10 DEMs blockade in MCL subset.MethodsA panel of MCL cell lines (Jeko-1, Granta-519, Mino) has been analyzed for CD24 surface expression by flow cytometry (FC) (clone SN3). Consequently, we performed co-culture experiments with MCL cell lines and macrophages from healthy donors. Briefly, Peripheral Blood Mononucleated Cells (PBMC) were collected from healthy volunteers through density gradient centrifugation technique. CD14+ monocytes were isolated through CD14 Microbeads isolation kit and cultured in plates with 50 ng/ml human GM-CSF for 7-9 days. In order to create M2-like Siglec-10+ TAM, 50 ng/ml human IL-10 and 50 ng/ml human TGF-β 1 were added on days 3-4 of differentiation until use on days 7-9. Siglec-10 expression on TAM was checked by FC (clone 5G6).M2-like macrophages were then collected and co-cultured with CFSE-labelled MCL target cells for 1-2 hours in a serum-free medium. Anti-CD24 moAb (clone SN3) or the appropriate IgG 1 isotype control were added at a concentration of 10 μg/ml. Phagocytosis was then stopped on ice and CD11b-PE staining (anti-CD11b moAb, clone REA713) was performed to identify human macrophages by FC.Phagocytosis was measured as the number of CD11b+/CFSE+ macrophages, quantified as a percentage of the total CD11b+ macrophages. Each phagocytosis reaction was performed in technical triplicate and phagocytosis was normalized to the highest technical replicate per donor in order to consider raw phagocytic level among donor-derived macrophages.ResultsMCL cell lines express surface CD24 by FC, with higher levels in Mino cell line (Figure 1A). Differentiated M2-like macrophages showed an upregulation of Siglec-10 expression after immunosuppressive stimuli, which is fundamental owing that Siglec-10 is the ligand of CD24 (Figure 1B).As pertains to the phagocytic assay, we documented an improvement of phagocytosis when M2-like macrophages and MCL cell lines were co-cultured together with anti-CD24 moAb (Figure 2 and Figure 3A). Furthermore, it is worth mentioning that phagocytosis seemed to be much higher in MCL cell lines with higher surface levels of CD24 (e.g., Mino), presenting increased number of CD11b+/CFSE+ M2-like TAM by FC (Figure 3B).ConclusionsMCL was found to be sensitive to CD24/Siglec-10 DEMs blockade when co-cultured with M2-like macrophages in vitro. We can argue that most of the observed increase of phagocytosis after the addition of anti-CD24 moAb may be secondary to loss of CD24 signalling rather than Fc-mediated opsonization, as already documented in previous analysis about solid cancer (Barkal, Nature. 2019). We can therefore hypothesize that the blockade of this DEMs pathway can improve phagocytosis in a non-opsonization manner in NHL as well.Furthermore, CD24 surface density seemed to be positively correlated to the intensity of phagocytic activity, suggesting that MCL subtypes expressing higher CD24 levels are much more dependent on this DEMs pathway than others with low CD24 density.Overall, CD24 turned out to be a potential immunotherapeutic target in MCL, aiming at improving innate immune system through DEMs blockade. In vivo studies are needed to confirm the activity we documented in vitro in this NHL subset. [Display omitted] DisclosuresGambacorti-Passerini: Bristol-Myers Squibb: Consultancy; Pfizer: Honoraria, Research Funding.

Cleavage of the Perlecan-Semaphorin 3A-Plexin A1-Neuropilin-1 (PSPN) Complex by Matrix Metalloproteinase 7/Matrilysin Triggers Prostate Cancer Cell Dyscohesion and Migration.

The Perlecan-Semaphorin 3A-Plexin A1-Neuropilin-1 (PSPN) Complex at the cell surface of prostate cancer (PCa) cells influences cell–cell cohesion and dyscohesion. We investigated matrix metalloproteinase-7/matrilysin (MMP-7)’s ability to digest components of the PSPN Complex in bone metastatic PCa cells using in silico analyses and in vitro experiments. Results demonstrated that in addition to the heparan sulfate proteoglycan, perlecan, all components of the PSPN Complex were degraded by MMP-7. To investigate the functional consequences of PSPN Complex cleavage, we developed a preformed microtumor model to examine initiation of cell dispersion after MMP-7 digestion. We found that while perlecan fully decorated with glycosaminoglycan limited dispersion of PCa microtumors, MMP-7 initiated rapid dyscohesion and migration even with perlecan present. Additionally, we found that a bioactive peptide (PLN4) found in perlecan domain IV in a region subject to digestion by MMP-7 further enhanced cell dispersion along with MMP-7. We found that digestion of the PSPN Complex with MMP-7 destabilized cell–cell junctions in microtumors evidenced by loss of co-registration of E-cadherin and F-actin. We conclude that MMP-7 plays a key functional role in PCa cell transition from a cohesive, indolent phenotype to a dyscohesive, migratory phenotype favoring production of circulating tumor cells and metastasis to bone.

A subcentimeter duodenal neuroendocrine neoplasm with a liver metastasis upgraded to G3: a case report

BackgroundAlthough duodenal neuroendocrine neoplasms (DuNENs) usually have indolent phenotypes, some DuNENs exhibit aggressive clinical manifestations. Tumor size > 1 cm, lymph node metastasis, and high grade have been associated with poor prognosis. However, preoperative risk evaluation is often difficult, because Ki-67 index on biopsy is frequently underestimated due to the intratumor heterogeneity. Here, we present a case of a subcentimeter DuNEN with a low Ki-67 index on endoscopic biopsy, who developed lymph node metastasis and high-grade liver metastasis.Case presentationThe patient was a 52-year-old female who presented an epigastric pain. Esophagogastroduodenoscopy revealed a duodenal submucosal lesion with a size of 8 mm. The endoscopic biopsy showed DuNEN with a Ki-67 index of 3.3% (G2 categorized by the World Health Organization 2019 classification). We performed an open partial duodenectomy with adjacent lymph node dissection. Pathological examination of the resected specimens revealed a Ki-67 index of 13.5% (G2) in the “hot spot” and lymph node metastasis. A hepatic low-density area detected on preoperative contrast-enhanced computed tomography appeared to be a liver metastasis on postoperative gadoxetic acid-enhanced magnetic resonance imaging. Subsequently, we performed a laparoscopic partial hepatectomy. Pathological examination of the liver specimen showed a metastatic neuroendocrine tumor with a Ki-67 index of 27.5% (NET-G3). The patient has been alive for 14 months since the hepatectomy.ConclusionsThis case shows the possibility of high malignant potential of DuNEN even if the primary lesion is < 1 cm and has a low Ki-67 index on biopsy.

Neuropathy with IgM Gammopathy: Incidence, Characteristics and Management, a Rory Morrison W.M.U.K Registry Analysis

Neuropathy with IgM Gammopathy: Incidence, Characteristics and Management, a Rory Morrison W.M.U.K Registry Analysis

Outcomes of Active Surveillance Versus Initial Treatment for Nodular Lymphocyte Predominant Hodgkin Lymphoma: A National Cancer Database (NCDB) Analysis of 2,480 Patients

Introduction Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) is a unique and clinically distinct subtype of Hodgkin lymphoma (HL), comprising approximately 5% of all HL cases with an annual incidence of about 1-2 cases per million. Compared with classical HL (cHL), NLPHL is more likely to present with limited stage and a more indolent clinical course. Despite these favorable traits, systemic chemoimmunotherapies and/or radiation are often used for initial treatment. Deaths directly from NLPHL are uncommon, with mortality in these patients often attributable to treatment-related toxicities or transformation to aggressive non-Hodgkin B-cell lymphomas. There is emerging evidence that NLPHL can be treated more conservatively. Active Surveillance (AS), a strategy by which initial treatment is deferred in favor of close observation, has been evaluated in single-institution retrospective studies spanning decades. Borchmannet alreported comparable overall survival (OS) for patients managed with AS versus upfront treatment (Blood, 2019). While encouraging, additional contemporary data are needed to determine if AS is a safe option for NLPHL patients, given advances in supportive care, addition of anti-CD20 therapies, improved radiation delivery, and better diagnostic methods. This retrospective National Cancer Database (NCDB) study evaluates the effect of initial treatment modality on overall survival in a contemporary population of patients with NLPHL to determine if initial AS has comparable OS when compared with initial treatment. Methods The National Cancer Database (NCDB) is a nationwide oncology outcomes database for more than 1500 accredited cancer programs in the United States. The NCDB was queried for all patients with the diagnosis of NLPHL, defined by histology code 9659. Filters for inclusion included year of diagnosis from 2010 to 2015, B-cell/pre-B/B-precursor histologic subtype, known treatment status, and with survival data available. Demographic, socioeconomic, treatment modality, and clinical factors such as stage and Charlson-Deyo comorbidity indices were summarized. Chi-square tests were used to correlate factors with treatment status. Kaplan-Meier methods were used to estimate overall survival, and log rank test was used to compare OS between patient groups. Cox proportional hazard model was used to associate patient characteristics with OS, and backwards elimination was used to identify the final Cox model, starting from all factors in univariate analysis. Results A total of 2,480 patients with NLPHL diagnosed between 2010 and 2015 were included. Of these, 553 patients were older than 60 years (22.3%), 1,616 were male (65%), and 2,110 had a Charlson-Deyo score of 0 (85%) while 370 had a score of ≥1 (15%). 1,627 had Stage I-II disease (65.6%) while 731 had Stage III-IV disease (29.5%). Overall, 2,330 patients were alive (94%) and 150 were deceased (6%), with a median follow-up of 36.8 months (range 0.1 to 94.3 months). Initial management options included: treatment (radiation, chemo/immunotherapy, and/or surgery), no treatment (e.g. palliative care only), or AS. 2,309 patients (93.1%) were initially treated (IT), 103 (4.15%) received no treatment (NT) and 68 patients (2.74%) underwent AS. OS by treatment strategy is shown in Figure 1. In univariate analysis, there was no OS difference between IT vs AS (HR 0.71; 95% CI 0.31-1.61, P=0.41) or NT vs. AS (HR 2.03; 95% CI 0.75-5.51; P= 0.16), but there was a significant difference between NT and IT (HR 2.87; 95% CI 1.56-5.32, P=0.0008). In the final Cox multivariate analysis, there was no significant difference between three treatment groups (overall P=0.10). Age &amp;gt;60, male gender, those with government insurance, Charlson-Deyo score ≥1, and Stage IV were all associated with decreased OS (Table 1). Conclusion In this large NCDB outcomes analysis of 2,480 NLPHL patients, those selected for AS had no difference in overall survival compared to patients who were initially treated. This lends support to emerging evidence that AS is a viable option for a subset newly diagnosed NLPHL patients, as is routine for indolent non-Hodgkin Lymphoma. Future study is needed to identify clinical features associated with a more indolent NLPHL phenotype that may be amendable to less intense initial management. Disclosures Hill: Karyopharm:Consultancy, Honoraria, Research Funding;Takeda:Research Funding;Celgene:Consultancy, Honoraria, Research Funding;BMS:Consultancy, Honoraria, Research Funding;Novartis:Consultancy, Honoraria;Kite, a Gilead Company:Consultancy, Honoraria, Research Funding;AstraZenica:Consultancy, Honoraria, Research Funding;Beigene:Consultancy, Honoraria, Research Funding;Pharmacyclics:Consultancy, Honoraria, Research Funding;Abbvie:Consultancy, Honoraria, Research Funding;Genentech:Consultancy, Honoraria, Research Funding.

A 30-Year Long-Term Experience in Appendix Neuroendocrine Neoplasms-Granting a Positive Outcome.

Neuroendocrine neoplasms (NENs) are the most common tumor of the appendix and have an excellent prognosis. Appendiceal tumors diagnosed between 1989 and 2019 were reviewed, and clinical data were collected from patient files. Part of the series was immuno-profiled for markers related to cell cycle proliferation and/or senescence-type, apoptotic, and metastatic potential. Appendix NENs were detected in 74 patients, with 0.47% of incidence per appendectomy. The median age of the patients was 21.5 years, with two age peaks of incidence at 17.0 and 55.2 years. The median tumors size was 5.8 mm, and most were smaller than 10 mm. Lymphovascular and perineural invasion, as well as necrosis, was associated with larger tumor size. G1 tumors composed 96.0% of the cohort. The presence of moderate/strong p16 and the absent/low Bcl-2 expression was frequently observed and associated with a smaller size. This study represents one of the largest cohorts and with a long follow-up. For tumors smaller than 10 mm appendicectomy was sufficient as a curative procedure, as revealed by the good outcome. This series presented a 100% disease-free survival. The indolent phenotype of appendix NENs is supported by the expression of markers that point towards a strong inhibition of cell replication and growth inhibition.

Persistent asymptomatic or mild symptomatic hyperCKemia due to mutations in ANO5: the mildest end of the anoctaminopathies spectrum.

The ANO5 gene encodes for anoctamin-5, a chloride channel involved in muscle cell membrane repair. Recessive mutations in ANO5 are associated with muscular diseases termed anoctaminopathies, which are characterized by proximal or distal weakness, or isolated hyperCKemia. We present the largest series of patients with asymptomatic/paucisymptomatic anoctaminopathy reported so far, highlighting their clinical and radiological characteristics. Twenty subjects were recruited retrospectively from the Neuromuscular Disorders Units database of two national reference centers. All had a confirmed genetic diagnosis (mean age of diagnosis was 48years) established between 2015 and 2019. Clinical and complementary data were evaluated through clinical records. None of the patients complained about weakness or showed abnormal muscular balance. Among paucisymptomatic patients, the main complaints or findings were generalized myalgia, exercise intolerance and calf hypertrophy, occasionally associated with calf pain. All patients showed persistent hyperCKemia, ranging from mild-moderate to severe. Muscle biopsy revealed inflammatory changes in three cases. Muscle magnetic resonance imaging revealed typical signs (preferential involvement of adductor and gastrocnemius muscles) in all but one patient. In two cases, abnormal findings were detectable only in STIR sequences (not in T1). Three patients showed radiological progression despite remaining asymptomatic. Twelve different mutations in ANO5 were detected, of which seven are novel. Recessive mutations in ANO5 are a frequent cause of undiagnosed asymptomatic/paucisymptomatic hyperCKemia. Patients with an apparent indolent phenotype may show muscle involvement in complementary tests (muscle biopsy and imaging), which may progress over time. Awareness of anoctaminopathy as the cause of nonspecific muscular complaints or of isolated hyperCKemia is essential to correctly diagnose affected patients.

Splanchnic vein thromboses associated with myeloproliferative neoplasms: An international, retrospective study on 518 cases.

Myeloproliferative Neoplasms (MPN) course can be complicated by thrombosis involving unusual sites as the splanchnic veins (SVT). Their management is challenging, given their composite vascular risk. We performed a retrospective, cohort study in the framework of the International Working Group for MPN Research and Treatment (IWG-MRT), and AIRC-Gruppo Italiano Malattie Mieloproliferative (AGIMM). A total of 518 MPN-SVT cases were collected and compared with 1628 unselected, control MPN population, matched for disease subtype. Those with MPN-SVT were younger (median 44 years) and enriched in females compared to controls; PV (37.1%) and ET (34.4%) were the most frequent diagnoses. JAK2V617F mutation was highly prevalent (90.2%), and 38.6% of cases had an additional hypercoagulable disorder. SVT recurrence rate was 1.6 per 100 patient-years. Vitamin K-antagonists (VKA) halved the incidence of recurrence (OR 0.48), unlike cytoreduction (OR 0.96), and were not associated with overall or gastrointestinal bleeding in multivariable analysis. Esophageal varices were the only independent predictor for major bleeding (OR 17.4). Among MPN-SVT, risk of subsequent vascular events was skewed towards venous thromboses compared to controls. However, MPN-SVT clinical course was overall benign: SVT were enriched in PMF with lower IPSS, resulting in significantly longer survival than controls; survival was not affected in PV and slightly reduced in ET. MPN-U with SVT (n = 55) showed a particularly indolent phenotype, with no signs of disease evolution. In the to-date largest, contemporary cohort of MPN-SVT, VKA were confirmed effective in preventing recurrence, unlike cytoreduction, and safe; the major risk factor for bleeding was esophageal varices that therefore represent a major therapeutic target.

IBS23.01 Radiotherapy of OMD in Daily Clinical Practice

IBS23.01 Radiotherapy of OMD in Daily Clinical Practice

Clinical Antibody Mediated Rejection of Lung is Not One Disease, but Includes Distinct Obstructive, Restrictive and Indolent Phenotypes

Purpose Chronic lung allograft dysfunction (CLAD) is the major determinant of mortality in lung transplant (LTX) recipients after 1 year. CLAD is strongly associated with de-novo HLA donor specific antibodies (DSA), but can present as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). The term clinical antibody mediated rejection (AMR) is often used to refer to any patient with possible or probable AMR by ISHLT criteria, but this group may include more than one disease. Methods Hierarchical cluster analysis of LTX recipients treated for Clinical AMR 2008-18 at a single center, grouped by radiological opacities and change of FEV1/FVC. P-values adjusted for multi-comparisons (Bonferroni). Results Of 118 patients, by ISHLT criteria, none had definite AMR, 18% probable, 56% possible and 26% were unclassifiable. AMR grade was not correlated with specific clinical features, outcome or treatment response. Cluster analysis identified 3 clinical phenotypes: acute obstruction, restriction and indolent (O: R: I). Rates of possible and probable AMR were similar in each group. Clusters differed in the patterns of FEV1 (figure 1), FVC and ratio (p Conclusion The current criteria for AMR do not describe one disease. We identified 3 main phenotypes with distinct clinical features, outcomes and treatment responses. Clinically validated acute phenotypes are needed.

Abstract PD4-10: 18F-fluoroestradiol (FES) and 18F-fluorodeoxyglucose (FDG) PET imaging in staging extent of disease in metastatic lobular breast cancer

Abstract Background: The histology and pattern of spread in lobular breast cancer has presented challenges in estimating extent of disease and identifying treatment options. 18F-FES is an estrogen analogue PET imaging tracer which measures tumor ER expression at multiple tumor sites simultaneously and predicts response to endocrine therapy. We analyzed FES-PET and FDG-PET SUV uptake in patients with metastatic lobular and ductal carcinoma to identify sites of tumor and responsiveness to therapy. Methods: We retrospectively reviewed FES and FDG SUV uptake between ER+ lobular (n = 36) and ductal (n= 173, including 6 men) metastatic breast cancer patients enrolled in various institutional studies. Up to 3 lesions in each patient were evaluated by FES SUVmax and/or FDG SUVmax for a total of 475 lesions in FES images and 462 lesions in FDG images. Classification into three categories (low FDG, high FDG/high FES, and high FDG/low FES) was generated using recursive portioning with 5-fold internal cross validation. Using a Pearson Chi-squared test, we compared degree of uptake in FES and FDG between lobular and ductal carcinomas. We used linear mixed effects model to assess association of FES SULmean3 (Lean body mass adjusted SUV) and FDG SULmean3 with histology. Overall survival (OS), from time of FES-PET scan to death, and progression free survival (PFS) was evaluated between classification groups in both histologies using Kaplan-Meier curves and Cox model. Results: In patients with metastatic breast cancer, 72 patients had low FDG, 96 had high FES/high FDG, and 41 with high FES/low FDG. Lobular lesions tended to have a higher proportion of patients in the risk group with lower FDG (42% vs 33%) and a lower proportion in the risk group with high FDG/low FES (11% vs 21%) but the difference was not statistically significant (p = 0.32). Mean (range) FES SULmean3 and FDG SULmax3 respectively for ductal was 1.38 (0.10, 6.7) and 3.17 (0.88, 12.26) and for lobular was 1.42 (0.34, 3.43) and 3.13 (1.04, 13.87). There was no significant difference between in FES SULmean3 and FDG SULmax3 between histologies. Following FES-PET imaging, patients with lobular carcinomas and low FDG demonstrated a higher median survival time (7.7 years) compared to high FDG/low FES (4.3 years) and high FDG/high FES (2.6 years). Similarly, patients with ductal carcinomas and low FDG had an improved median survival time (5.6 years) compared to both high FDG/high FES (2.9 years) and high FDG/low FES (2.5 years). However, the interaction between histology and the FDG/FES classifications was not significant (p = 0.86). Across a variety of tumor sites, lobular histology can be detected by both FES and FDG with no difference between the imaging modalities. Conclusions: In the metastatic setting, quantitative FES and FDG can be used to discriminate indolent and aggressive phenotypes in both lobular and ductal breast cancer. A greater proportion of lobular carcinoma lesions had higher FES/lower FDG and would be anticipated to be more sensitive to endocrine therapy. Further prospective trials are needed to confirm the utility of FES to stage extent of disease in metastatic breast cancer. Citation Format: Manohar PM, Peterson LM, Wu V, Jenkins IC, Novakova-Jiresova A, Specht JM, Link JM, Krohn KA, Kinahan PE, Mankoff DA, Linden HM. 18F-fluoroestradiol (FES) and 18F-fluorodeoxyglucose (FDG) PET imaging in staging extent of disease in metastatic lobular breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD4-10.

Combined genetic and epigenetic alterations of the TERT promoter affect clinical and biological behavior of bladder cancer.

In urothelial bladder cancer (UBC), risk stratification remains an important unmet need. Limitless self‐renewal, governed by TERT expression and telomerase activation, is crucial for cancer progression. Thus, telomerase activation through the interplay of mutations (TERTpMut) and epigenetic alterations in the TERT promoter may provide further insight into UBC behavior. Here, we investigated the combined effect of TERTpMut and the TERT Hypermethylated Oncological Region (THOR) status on telomerase activation and patient outcome in a UBC international cohort (n = 237). We verified that TERTpMut were frequent (76.8%) and present in all stages and grades of UBC. Hypermethylation of THOR was associated with higher TERT expression and higher‐risk disease in nonmuscle invasive bladder cancers (NMIBC). TERTpMut alone predicted disease recurrence (HR: 3.18, 95%CI 1.84 to 5.51, p < 0.0001) but not progression in NMIBC. Combined THORhigh/TERTpMut increased the risk of disease recurrence (HR 5.12, p < 0.0001) and progression (HR 3.92, p = 0.025). Increased THOR hypermethylation doubled the risk of stage progression of both TERTpwt and TERTpMut NMIBC. These results highlight that both mechanisms are common and coexist in bladder cancer and while TERTpMut is an early event in bladder carcinogenesis THOR hypermethylation is a dynamic process that contributes to disease progression. While the absence of alterations comprises an extremely indolent phenotype, the combined genetic and epigenetic alterations of TERT bring additional prognostic value in NMIBC and provide a novel insight into telomere biology in cancer.

Mutations and Copy Number Changes Predict Progression from Smoldering Myeloma to Symptomatic Myeloma in the Era of Novel IMWG Criteria

Mutations and Copy Number Changes Predict Progression from Smoldering Myeloma to Symptomatic Myeloma in the Era of Novel IMWG Criteria

Analysis of regulator of G-protein signalling 2 (RGS2) expression and function during prostate cancer progression

Prostate cancer (PC) represents the second highest cancer-related mortality among men and the call for biomarkers for early discrimination between aggressive and indolent forms is essential. Downregulation of Regulator of G-protein signaling 2 (RGS2) has been shown in PC, however the underlying mechanism has not been described. Aberrant RGS2 expression has also been reported for other carcinomas in association to both positive and negative prognosis. In this study, we assessed RGS2 expression during PC progression in terms of regulation and impact on tumour phenotype and evaluated its prognostic value. Our experimental data suggest that the RGS2 downregulation seen in early PC is caused by hypoxia. In line with the common indolent phenotype of a primary PC, knockdown of RGS2 induced epithelial features and impaired metastatic properties. However, increased STAT3, TWIST1 and decreased E-cadherin expression suggest priming for EMT. Additionally, improved tumour cell survival and increased BCL-2 expression linked decreased RGS2 levels to fundamental tumour advantages. In contrast, high RGS2 levels in advanced PC were correlated to poor patient survival and a positive metastatic status. This study describes novel roles for RGS2 during PC progression and suggests a prognostic potential discriminating between indolent and metastatic forms of PC.

Abstract LB-345: Unique molecular identifiers of indolent versus aggressive phenotyping in non-Hodgkin lymphoma: Spotlight on SMZL

Abstract Splenic marginal zone lymphoma (SMZL) is an indolent, non-Hodgkin's lymphoma that lacks clear genotypic classification. Approximately 30% of all SMZL cases will become aggressive or undergo transformation to a more lethal lymphoma. Hence, the main purpose of this study was to broadly characterize the molecular profiles of SMZL cases, compared with healthy B-cell controls and other B-cell lymphomas (BCLs), in an effort to delineate the variable malignant presentations. We aimed to identify a unique indolent and aggressive gene expression signature among SMZL cases in order to potentially provide prognostic value. We conducted a meta-analysis of previously published gene expression data to identify genes most dysregulated in SMZL. We aimed to delineate the “indolent phenotype” and the “aggressive phenotype” by comparing SMZL to more aggressive BCLs as well as healthy B-cell controls, in order to extract a prognostic gene expression profile specific to SMZL. Markers potentially demonstrating an “aggressive” signature were those significantly up or down regulated in SMZL samples when compared to BCLs and healthy controls. The most upregulated genes in SMZL included PPBP, CXCL6, HBB, KAZN, NTN4, SLC40A1, MAFB, ATP1B1, and C1QB, while the most downregulated genes were RASSF6, RGS13, ELL3, LHFPL2, and SYB. Pathways impacted include immune defense (inclusive of leukocyte chemotaxis), motility (inclusive of lamellipodium assembly), cell proliferation, and many other mechanisms. Contrarily, 19 key markers of potential oncogenic indolency (i.e. down regulated compared with other, aggressive B-cell lymphomas, but upregulated compared with healthy B-cells) were also identified: ABI3BP, GPNMB, LUM, CCL19, ADAMDEC1, GJA1, MGP, SERPINF1, COL6A3, C3, RARRES1, FN1, CCL18, PRRX1, RGS5, CHI3L1, COL5A2, LOXL1, and ANKRD29. Additionally, a transcription factor, ZC3H7B, known to play a role in BCL6 repression as a result of a fusion with BCOR, is uniquely down regulated in SMZL compared with normal B controls while being up regulated when compared to similar BCLs. This exclusive expression of ZC3H7B represents a unique marker for SMZL identification compared to other BCLs. The aforementioned gene expression profile provides SMZL identification potential, and more importantly, these unique gene signatures potentially identify markers of indolent progression due to their differential expression from more aggressive B-cell lymphoma counterparts. Further investigations into the translatability of these gene expressions and their resultant impacted pathways will be evaluated for diagnostic and prognostic significance using immunohistochemistry, and hypothesized targets will be evaluated in vitro. Ultimately, we expect that the unique gene expression profile identified in this study will provide translatable results to assist with patient staging in SMZL. Citation Format: Jacob E. Robinson, Christine E. Cutucache. Unique molecular identifiers of indolent versus aggressive phenotyping in non-Hodgkin lymphoma: Spotlight on SMZL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-345.