Functional Copy-Number Alterations as Diagnostic and Prognostic Biomarkers in Neuroendocrine Tumors.

Functional copy-number alterations (fCNAs) are DNA copy-number changes with concordant differential gene expression. These are less likely to be bystander genetic lesions and could serve as robust and reproducible tumor biomarkers. To identify candidate fCNAs in neuroendocrine tumors (NETs), we integrated chromosomal microarray (CMA) and RNA-seq differential gene-expression data from 31 pancreatic (pNETs) and 33 small-bowel neuroendocrine tumors (sbNETs). Tumors were resected from 47 early-disease-progression (<24 months) and 17 late-disease-progression (>24 months) patients. Candidate fCNAs that accurately differentiated these groups in this discovery cohort were then replicated using fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded (FFPE) tissues in a larger validation cohort of 60 pNETs and 82 sbNETs (52 early- and 65 late-disease-progression samples). Logistic regression analysis revealed the predictive ability of these biomarkers, as well as the assay-performance metrics of sensitivity, specificity, and area under the curve. Our results indicate that copy-number changes at chromosomal loci 4p16.3, 7q31.2, 9p21.3, 17q12, 18q21.2, and 19q12 may be used as diagnostic and prognostic NET biomarkers. This involves a rapid, cost-effective approach to determine the primary tumor site for patients with metastatic liver NETs and to guide risk-stratified therapeutic decisions.

Mapping the Evolutionary Space of SARS-CoV-2 Variants to Anticipate Emergence of Subvariants Resistant to COVID-19 Therapeutics.

New sublineages of SARS-CoV-2 variants-of-concern (VOCs) continuously emerge with mutations in the spike glycoprotein. In most cases, the sublineage-defining mutations vary between the VOCs. It is unclear whether these differences reflect lineage-specific likelihoods for mutations at each spike position or the stochastic nature of their appearance. Here we show that SARS-CoV-2 lineages have distinct evolutionary spaces (a probabilistic definition of the sequence states that can be occupied by expanding virus subpopulations). This space can be accurately inferred from the patterns of amino acid variability at the whole-protein level. Robust networks of co-variable sites identify the highest-likelihood mutations in new VOC sublineages and predict remarkably well the emergence of subvariants with resistance mutations to COVID-19 therapeutics. Our studies reveal the contribution of low frequency variant patterns at heterologous sites across the protein to accurate prediction of the changes at each position of interest.

The Influence of a Genetic Variant in CCDC78 on LMNA-Associated Skeletal Muscle Disease.

Mutations in the LMNA gene-encoding A-type lamins can cause Limb-Girdle muscular dystrophy Type 1B (LGMD1B). This disease presents with weakness and wasting of the proximal skeletal muscles and has a variable age of onset and disease severity. This variability has been attributed to genetic background differences among individuals; however, such variants have not been well characterized. To identify such variants, we investigated a multigeneration family in which affected individuals are diagnosed with LGMD1B. The primary genetic cause of LGMD1B in this family is a dominant mutation that activates a cryptic splice site, leading to a five-nucleotide deletion in the mature mRNA. This results in a frame shift and a premature stop in translation. Skeletal muscle biopsies from the family members showed dystrophic features of variable severity, with the muscle fibers of some family members possessing cores, regions of sarcomeric disruption, and a paucity of mitochondria, not commonly associated with LGMD1B. Using whole genome sequencing (WGS), we identified 21 DNA sequence variants that segregate with the family members possessing more profound dystrophic features and muscle cores. These include a relatively common variant in coiled-coil domain containing protein 78 (CCDC78). This variant was given priority because another mutation in CCDC78 causes autosomal dominant centronuclear myopathy-4, which causes cores in addition to centrally positioned nuclei. Therefore, we analyzed muscle biopsies from family members and discovered that those with both the LMNA mutation and the CCDC78 variant contain muscle cores that accumulated both CCDC78 and RyR1. Muscle cores containing mislocalized CCDC78 and RyR1 were absent in the less profoundly affected family members possessing only the LMNA mutation. Taken together, our findings suggest that a relatively common variant in CCDC78 can impart profound muscle pathology in combination with a LMNA mutation and accounts for variability in skeletal muscle disease phenotypes.

Prioritization of Fluorescence In Situ Hybridization (FISH) Probes for Differentiating Primary Sites of Neuroendocrine Tumors with Machine Learning.

Determining neuroendocrine tumor (NET) primary sites is pivotal for patient care as pancreatic NETs (pNETs) and small bowel NETs (sbNETs) have distinct treatment approaches. The diagnostic power and prioritization of fluorescence in situ hybridization (FISH) assay biomarkers for establishing primary sites has not been thoroughly investigated using machine learning (ML) techniques. We trained ML models on FISH assay metrics from 85 sbNET and 59 pNET samples for primary site prediction. Exploring multiple methods for imputing missing data, the impute-by-median dataset coupled with a support vector machine model achieved the highest classification accuracy of 93.1% on a held-out test set, with the top importance variables originating from the ERBB2 FISH probe. Due to the greater interpretability of decision tree (DT) models, we fit DT models to ten dataset splits, achieving optimal performance with k-nearest neighbor (KNN) imputed data and a transformation to single categorical biomarker probe variables, with a mean accuracy of 81.4%, on held-out test sets. ERBB2 and MET variables ranked as top-performing features in 9 of 10 DT models and the full dataset model. These findings offer probabilistic guidance for FISH testing, emphasizing the prioritization of the ERBB2, SMAD4, and CDKN2A FISH probes in diagnosing NET primary sites.

Mosaicism in BRPF1-Related Neurodevelopmental Disorder: Report of Two Sisters and Literature Review.

Bromodomain and PHD finger containing 1 (BRPF1)-related neurodevelopmental disorder is characterized by intellectual disability, developmental delay, hypotonia, dysmorphic facial features, ptosis, and blepharophimosis. Both de novo and inherited pathogenic variants have been previously reported in association with this disorder. We report two affected female siblings with a novel variant in BRPF1 c.2420_2433del (p.Q807Lfs∗27) identified through whole-exome sequencing. Their history of mild intellectual disability, speech delay, attention deficient hyperactivity disorder (ADHD), and ptosis align with the features previously reported in the literature. The absence of the BRPF1 variant in parental buccal samples provides evidence of a de novo frameshift pathogenic variant, most likely as a result of parental gonadal mosaicism, which has not been previously reported. The frameshift pathogenic variant reported here lends further support to haploinsufficiency as the underlying mechanism of disease. We review the literature, compare the clinical features seen in our patients with others reported, and explore the possibility of genotype-phenotype correlation based on the location of pathogenic variants in BRPF1. Our study helps to summarize available knowledge and report the first case of a de novo frameshift pathogenic variant in BRPF1 in two siblings with this neurodevelopmental disorder.

CDK4/6-MEK Inhibition in MPNSTs Causes Plasma Cell Infiltration, Sensitization to PD-L1 Blockade, and Tumor Regression.

PURPOSE: Malignant peripheral nerve sheath tumors (MPNST) are lethal, Ras-driven sarcomas that lack effective therapies. We investigated effects of targeting cyclin-dependent kinases 4 and 6 (CDK4/6), MEK, and/or programmed death-ligand 1 (PD-L1) in preclinical MPNST models. EXPERIMENTAL DESIGN: Patient-matched MPNSTs and precursor lesions were examined by FISH, RNA sequencing, IHC, and Connectivity-Map analyses. Antitumor activity of CDK4/6 and MEK inhibitors was measured in MPNST cell lines, patient-derived xenografts (PDX), and de novo mouse MPNSTs, with the latter used to determine anti-PD-L1 response. RESULTS: Patient tumor analyses identified CDK4/6 and MEK as actionable targets for MPNST therapy. Low-dose combinations of CDK4/6 and MEK inhibitors synergistically reactivated the retinoblastoma (RB1) tumor suppressor, induced cell death, and decreased clonogenic survival of MPNST cells. In immune-deficient mice, dual CDK4/6-MEK inhibition slowed tumor growth in 4 of 5 MPNST PDXs. In immunocompetent mice, combination therapy of de novo MPNSTs caused tumor regression, delayed resistant tumor outgrowth, and improved survival relative to monotherapies. Drug-sensitive tumors that regressed contained plasma cells and increased cytotoxic T cells, whereas drug-resistant tumors adopted an immunosuppressive microenvironment with elevated MHC II-low macrophages and increased tumor cell PD-L1 expression. Excitingly, CDK4/6-MEK inhibition sensitized MPNSTs to anti-PD-L1 immune checkpoint blockade (ICB) with some mice showing complete tumor regression. CONCLUSIONS: CDK4/6-MEK inhibition induces a novel plasma cell-associated immune response and extended antitumor activity in MPNSTs, which dramatically enhances anti-PD-L1 therapy. These preclinical findings provide strong rationale for clinical translation of CDK4/6-MEK-ICB targeted therapies in MPNST as they may yield sustained antitumor responses and improved patient outcomes.

CRELD1 variants are associated with bicuspid aortic valve in Turner syndrome.

Turner syndrome (TS) is a chromosomal disorder caused by complete or partial loss of the second sex chromosome and exhibits phenotypic heterogeneity, even after accounting for mosaicism and karyotypic variation. Congenital heart defects (CHD) are found in up to 45 percent of girls with TS and span a phenotypic continuum of obstructive left-sided lesions, with bicuspid aortic valve (BAV) being the most common. Several recent studies have demonstrated a genome-wide impact of X chromosome haploinsufficiency, including global hypomethylation and altered RNA expression. The presence of such broad changes to the TS epigenome and transcriptome led others to hypothesize that X chromosome haploinsufficiency sensitizes the TS genome, and several studies have demonstrated that a second genetic hit can modify disease susceptibility in TS. The objective of this study was to determine whether genetic variants in known heart developmental pathways act synergistically in this setting to increase the risk for CHD, specifically BAV, in TS. We analyzed 208 whole exomes from girls and women with TS and performed gene-based variant enrichment analysis and rare-variant association testing to identify variants associated with BAV in TS. Notably, rare variants in CRELD1 were significantly enriched in individuals with TS who had BAV compared to those with structurally normal hearts. CRELD1 is a protein that functions as a regulator of calcineurin/NFAT signaling, and rare variants in CRELD1 have been associated with both syndromic and non-syndromic CHD. This observation supports the hypothesis that genetic modifiers outside the X chromosome that lie in known heart development pathways may influence CHD risk in TS.

Genome-wide analysis of copy-number variation in humans with cleft lip and/or cleft palate identifies COBLL1, RIC1, and ARHGEF38 as clefting genes.

Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well established that common and rare sequence variants contribute to the formation of CL/P, but the contribution of copy-number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed; however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our cohort of individuals with clefts compared to control subjects, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR-Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.

A comprehensive list of human microdeletion and microduplication syndromes.

OBJECTIVE: The phenotypic spectrum of human microdeletion and microduplication syndromes (MMS) is heterogeneous but often involves intellectual disability, autism spectrum disorders, dysmorphic features and/or multiple congenital anomalies. While the common recurrent copy number variants (CNVs) which underlie these MMS have been well-studied, the expansion of clinical genomic testing has led to the identification of many rare non-recurrent MMS. To date, hundreds of unique MMS have been reported in the medical literature, and no single resource exists which compiles all these MMS in one location. This comprehensive list of MMS will aid further study of CNV disorders as well as serve as a resource for clinical laboratories performing diagnostic CNV testing. DATA DESCRIPTION: Here we provide a comprehensive list of MMS which have been reported in the medical literature to date. This list is sorted by genomic location, and for each MMS, we provide a list of publications for referral, as well as the consensus coordinates, representative region, shortest regions of overlap (SRO), and/or subregions where applicable.

TBX3 and EFNA4 Variant in a Family with Ulnar-Mammary Syndrome and Sagittal Craniosynostosis.

Ulnar-mammary syndrome (UMS) is a rare, autosomal dominant disorder characterized by anomalies affecting the limbs, apocrine glands, dentition, and genital development. This syndrome is caused by haploinsufficiency in the T-Box3 gene (TBX3), with considerable variability in the clinical phenotype being observed even within families. We describe a one-year-old female with unilateral, postaxial polydactyly, and bilateral fifth fingernail duplication. Next-generation sequencing revealed a novel, likely pathogenic, variant predicted to affect the canonical splice site in intron 3 of the TBX3 gene (c.804 + 1G > A, IVS3 + 1G > A). This variant was inherited from the proband's father who was also diagnosed with UMS with the additional clinical finding of congenital, sagittal craniosynostosis. Subsequent whole genome analysis in the proband's father detected a variant in the EFNA4 gene (c.178C > T, p.His60Tyr), which has only been reported to be associated with sagittal craniosynostosis in one patient prior to this report but reported in other cranial suture synostosis. The findings in this family extend the genotypic spectrum of UMS, as well as the phenotypic spectrum of EFNA4-related craniosynostosis.

PRC2 loss drives MPNST metastasis and matrix remodeling.

The histone methyltransferase PRC2 plays a complex role in cancer. Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with frequent loss-of-function mutations in PRC2 that are associated with poor outcome. Here, we identify a critical role for PRC2 loss in driving MPNST metastasis. PRC2-dependent metastatic phenotypes included increased collagen-dependent invasion, upregulation of matrix-remodeling enzymes, and elevated lung metastasis in orthotopic mouse models. Furthermore, clinical sample analysis determined that PRC2 loss correlated with metastatic disease, increased fibrosis, and decreased survival in patients with MPNSTs. These results may have broad implications for PRC2 function across multiple cancers and provide a strong rationale for investigating potential therapies targeting ECM-remodeling enzymes and tumor fibrosis to improve outcomes in patients with MPNSTs.

Additive and Interactive Genetically Contextual Effects of HbA1c on cg19693031 Methylation in Type 2 Diabetes.

Type 2 diabetes mellitus (T2D) has a complex genetic and environmental architecture that underlies its development and clinical presentation. Despite the identification of well over a hundred genetic variants and CpG sites that associate with T2D, a robust biosignature that could be used to prevent or forestall clinical disease has not been developed. Based on the premise that underlying genetic variation influences DNA methylation (DNAm) independently of or in combination with environmental exposures, we assessed the ability of local and distal gene x methylation (GxMeth) interactive effects to improve cg19693031 models for predicting T2D status in an African American cohort. Using genome-wide genetic data from 506 subjects, we identified a total of 1476 GxMeth terms associated with HbA1c values. The GxMeth SNPs map to biological pathways associated with the development and complications of T2D, with genetically contextual differences in methylation observed only in diabetic subjects for two GxMeth SNPs (rs2390998 AG vs. GG, p = 4.63 × 10-11, Δß = 13%, effect size = 0.16 [95% CI = 0.05, 0.32]; rs1074390 AA vs. GG, p = 3.93 × 10-4, Δß = 9%, effect size = 0.38 [95% CI = 0.12, 0.56]. Using a repeated stratified k-fold cross-validation approach, a series of balanced random forest classifiers with random under-sampling were built to evaluate the addition of GxMeth terms to cg19693031 models to discriminate between normoglycemic controls versus T2D subjects. The results were compared to those obtained from models incorporating only the covariates (age, sex and BMI) and the addition of cg19693031. We found a post-pruned classifier incorporating 10 GxMeth SNPs and cg19693031 adjusted for covariates predicted the T2D status, with the AUC, sensitivity, specificity and precision of the positive target class being 0.76, 0.81, 0.70 and 0.63, respectively. Comparatively, the AUC, sensitivity, specificity and precision using the covariates and cg19693031 were only 0.71, 0.74, 0.67 and 0.59, respectively. Collectively, we demonstrate correcting for genetic confounding of cg19693031 improves its ability to detect type 2 diabetes. We conclude that an integrated genetic-epigenetic approach could inform personalized medicine programming for more effective prevention and treatment of T2D.

Intron mutations and early transcription termination in Duchenne and Becker muscular dystrophy.

DMD pathogenic variants for Duchenne and Becker muscular dystrophy are detectable with high sensitivity by standard clinical exome analyses of genomic DNA. However, up to 7% of DMD mutations are deep intronic and analysis of muscle-derived RNA is an important diagnostic step for patients who have negative genomic testing but abnormal dystrophin expression in muscle. In this study, muscle biopsies were evaluated from 19 patients with clinical features of a dystrophinopathy, but negative clinical DMD mutation analysis. Reverse transcription-polymerase chain reaction or high-throughput RNA sequencing methods identified 19 mutations with one of three pathogenic pseudoexon types: deep intronic point mutations, deletions or insertions, and translocations. In association with point mutations creating intronic splice acceptor sites, we observed the first examples of DMD pseudo 3'-terminal exon mutations causing high efficiency transcription termination within introns. This connection between splicing and premature transcription termination is reminiscent of U1 snRNP-mediating telescripting in sustaining RNA polymerase II elongation across large genes, such as DMD. We propose a novel classification of three distinct types of mutations identifiable by muscle RNA analysis, each of which differ in potential treatment approaches. Recognition and appropriate characterization may lead to therapies directed toward full-length dystrophin expression for some patients.

Sporadic hypothalamic hamartoma is a ciliopathy with somatic and bi-allelic contributions.

Hypothalamic hamartoma with gelastic seizures is a well-established cause of drug-resistant epilepsy in early life. The development of novel surgical techniques has permitted the genomic interrogation of hypothalamic hamartoma tissue. This has revealed causative mosaic variants within GLI3, OFD1 and other key regulators of the sonic-hedgehog pathway in a minority of cases. Sonic-hedgehog signalling proteins localize to the cellular organelle primary cilia. We therefore explored the hypothesis that cilia gene variants may underlie hitherto unsolved cases of sporadic hypothalamic hamartoma. We performed high-depth exome sequencing and chromosomal microarray on surgically resected hypothalamic hamartoma tissue and paired leukocyte-derived DNA from 27 patients. We searched for both germline and somatic variants under both dominant and bi-allelic genetic models. In hamartoma-derived DNA of seven patients we identified bi-allelic (one germline, one somatic) variants within one of four cilia genes-DYNC2I1, DYNC2H1, IFT140 or SMO. In eight patients, we identified single somatic variants in the previously established hypothalamic hamartoma disease genes GLI3 or OFD1. Overall, we established a plausible molecular cause for 15/27 (56%) patients. Here, we expand the genetic architecture beyond single variants within dominant disease genes that cause sporadic hypothalamic hamartoma to bi-allelic (one germline/one somatic) variants, implicate three novel cilia genes and reconceptualize the disorder as a ciliopathy.

Data on the utilization of paraneoplastic syndrome autoantibody testing at an academic medical center.

Paraneoplastic syndromes are rare conditions associated with characteristic autoantibodies produced by malignancy, although similar autoantibodies and clinical presentations may occur in the absence of any neoplasm. Testing for paraneoplastic syndromes often involves panels of autoantibody assays. While autoantibody testing may reveal or confirm actionable clinical diagnoses, inappropriate utilization of testing may be low yield and further lead to false positives that may confuse the clinical picture. There is thus opportunity to improve patient care by analyzing patterns of paraneoplastic autoantibody test utilization. The data in this article provides results from detailed retrospective review of patients tested by 7 autoantibody tests or test panels offered by two large reference laboratories in the United States. The data include 1,446 tests performed on 1,338 unique patients at an academic medical center. For all results, detailed chart review revealed main category of presenting symptoms, patient location at time of testing (either inpatient or outpatient), sex, age, whether cancer was present at the time of testing or later detected, and the specific results of the testing. The data are summarized by category of testing and specific autoantibodies.

The emerging role of somatic tumor sequencing in the treatment of urothelial cancer.

The development of rapid genome sequencing has greatly enhanced our understanding of the molecular biology underlying many malignancies. Whole exome sequencing has highlighted the individualistic nature of malignancies on a patient-to-patient basis and begun to revolutionize therapeutic approaches. In recent years, whole genome sequencing of urothelial malignancies has identified a host of somatic mutations which contribute to growth, progression, and metastasis of urothelial carcinoma of the bladder and upper tract urothelial carcinoma. As genetic sequencing continues, additional targets will be identified, allowing development of novel therapeutic agents targeting cancer on a molecular level, with the goal of delivering highly individualized care based on the underlying mutational profile of the patient's malignancy. In this review, we aim to discuss known genetic alterations of urothelial malignancy and the implications these mutations carry in terms of prognostication and development of targeted therapeutic agents. We will focus on RNA-expression profiling and genomic DNA profiling, with a focus on comprehensive whole exome and whole genome sequencing relative to selected urothelial carcinoma-associated genes and circulating tumor DNA analysis.

Sequential genetic testing of living-related donors for inherited renal disease to promote informed choice and enhance safety of living donation.

Living kidney donors (LKDs) with a family history of renal disease are at risk of kidney disease as compared to LKDs without such history suggesting that some LKDs may be pre-symptomatic for monogenic kidney disease. LKDs with related transplant candidates whose kidney disease was considered genetic in origin were selected for genetic testing. In each case, the transplant candidate was first tested to verify the genetic diagnosis. A genetic diagnosis was confirmed in 12 of 24 transplant candidates (ADPKD-PKD1: 6, ALPORT-COL4A3: 2, ALPORT-COL4A5: 1: nephronophthisis-SDCCAG8: 1; CAKUT-HNF1B and ADTKD-MUC1: 1 each) and 2 had variants of unknown significance (VUS) in phenotype-relevant genes. Focused genetic testing was then done in 20 of 34 LKDs. 12 LKDs screened negative for the familial variant and were permitted to donate; seven screened positive and were counseled against donation. One, the heterozygous carrier of a recessive disorder was also cleared. Six of seven LKDs with a family history of ADPKD were under 30 years and in 5, by excluding ADPKD, allowed donation to safely proceed. The inclusion of genetic testing clarified the diagnosis in recipient candidates, improving safety or informed decision-making in LKDs.

RABL6A Promotes Pancreatic Neuroendocrine Tumor Angiogenesis and Progression In Vivo.

Pancreatic neuroendocrine tumors (pNETs) are difficult-to-treat neoplasms whose incidence is rising. Greater understanding of pNET pathogenesis is needed to identify new biomarkers and targets for improved therapy. RABL6A, a novel oncogenic GTPase, is highly expressed in patient pNETs and required for pNET cell proliferation and survival in vitro. Here, we investigated the role of RABL6A in pNET progression in vivo using a well-established model of the disease. RIP-Tag2 (RT2) mice develop functional pNETs (insulinomas) due to SV40 large T-antigen expression in pancreatic islet ß cells. RABL6A loss in RT2 mice significantly delayed pancreatic tumor formation, reduced tumor angiogenesis and mitoses, and extended survival. Those effects correlated with upregulation of anti-angiogenic p19ARF and downregulation of proangiogenic c-Myc in RABL6A-deficient islets and tumors. Our findings demonstrate that RABL6A is a bona fide oncogenic driver of pNET angiogenesis and development in vivo.

Case report of a pseudo-isodicentric chromosome 9 resulting in mosaic trisomy 9.

Due to the variable presentation of mosaic chromosomal abnormalities, cases such as this are needed to define the phenotypic spectrum. It also highlights the importance of chromosome analysis to identify structural abnormalities that result in aneuploidy.

Development and comparison of novel bioluminescent mouse models of pancreatic neuroendocrine neoplasm metastasis.

Pancreatic neuroendocrine neoplasms (pNENs) are slow growing cancers of increasing incidence that lack effective treatments once they become metastatic. Unfortunately, nearly half of pNEN patients present with metastatic liver tumors at diagnosis and current therapies fail to improve overall survival. Pre-clinical models of pNEN metastasis are needed to advance our understanding of the mechanisms driving the metastatic process and for the development of novel, targeted therapeutic interventions. To model metastatic dissemination of tumor cells, human pNEN cell lines (BON1 and Qgp1) stably expressing firefly luciferase (luc) were generated and introduced into NSG immunodeficient mice by intracardiac (IC) or intravenous (IV) injection. The efficiency, kinetics and distribution of tumor growth was evaluated weekly by non-invasive bioluminescent imaging (BLI). Tumors formed in all animals in both the IC and IV models. Bioluminescent Qgp1.luc cells preferentially metastasized to the liver regardless of delivery route, mimicking the predominant site of pNEN metastasis in patients. By comparison, BON1.luc cells most commonly formed lung tumors following either IV or IC administration and colonized a wider variety of tissues than Qgp1.luc cells. These models provide a unique platform for testing candidate metastasis genes and anti-metastatic therapies for pNENs.