MRI Features for Identifying MYCN-amplified RB1 Wild-type Retinoblastoma.

Background MYCN-amplified RB1 wild-type (MYCNARB1+/+) retinoblastoma is a rare but clinically important subtype of retinoblastoma due to its aggressive character and relative resistance to typical therapeutic approaches. Because biopsy is not indicated in retinoblastoma, specific MRI features might be valuable to identify children with this genetic subtype. Purpose To define the MRI phenotype of MYCNARB1+/+ retinoblastoma and evaluate the ability of qualitative MRI features to help identify this specific genetic subtype. Materials and Methods In this retrospective, multicenter, case-control study, MRI scans in children with MYCNARB1+/+ retinoblastoma and age-matched children with RB1-/- subtype retinoblastoma were included (case-control ratio, 1:4; scans acquired from June 2001 to February 2021; scans collected from May 2018 to October 2021). Patients with histopathologically confirmed unilateral retinoblastoma, genetic testing (RB1/MYCN status), and MRI scans were included. Associations between radiologist-scored imaging features and diagnosis were assessed with the Fisher exact test or Fisher-Freeman-Halton test, and Bonferroni-corrected P values were calculated. Results A total of 110 patients from 10 retinoblastoma referral centers were included: 22 children with MYCNARB1+/+ retinoblastoma and 88 control children with RB1-/- retinoblastoma. Children in the MYCNARB1+/+ group had a median age of 7.0 months (IQR, 5.0-9.0 months) (13 boys), while children in the RB1-/- group had a median age of 9.0 months (IQR, 4.6-13.4 months) (46 boys). MYCNARB1+/+ retinoblastomas were typically peripherally located (in 10 of 17 children; specificity, 97%; P < .001) and exhibited plaque or pleomorphic shape (in 20 of 22 children; specificity, 51%; P = .011) with irregular margins (in 16 of 22 children; specificity, 70%; P = .008) and extensive retina folding with vitreous enclosure (specificity, 94%; P < .001). MYCNARB1+/+ retinoblastomas showed peritumoral hemorrhage (in 17 of 21 children; specificity, 88%; P < .001), subretinal hemorrhage with a fluid-fluid level (in eight of 22 children; specificity, 95%; P = .005), and strong anterior chamber enhancement (in 13 of 21 children; specificity, 80%; P = .008). Conclusion MYCNARB1+/+ retinoblastomas show distinct MRI features that could enable early identification of these tumors. This may improve patient selection for tailored treatment in the future. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Rollins in this issue.

Clinical challenges in interpreting multiple pathogenic mutations in single patients.

BACKGROUND: In the past two decades, genetic testing for cancer risk assessment has entered mainstream clinical practice due to the availability of low-cost panels of multiple cancer-associated genes. However, the clinical value of multiple-gene panels for cancer susceptibility is not well established, especially in cases where panel testing identifies more than one pathogenic variant. The risk for specific malignancies as a result of a mutated gene is complex and likely influenced by superimposed modifier variants and/or environmental effects. Recent data suggests that the combination of multiple pathogenic variants may be fewer than reported by chance, suggesting that some mutation combinations may be detrimental. Management of patients with "incidentally" discovered mutations can be particularly challenging, especially when established guidelines call for radical procedures (e.g. total gastrectomy in CDH1) in patients and families without a classic clinical history concerning for that cancer predisposition syndrome. CASE PRESENTATION: We present two cases, one of an individual and one of a family, with multiple pathogenic mutations detected by multi-gene panel testing to highlight challenges practitioners face in counseling patients about pathogenic variants and determining preventive and therapeutic interventions. CONCLUSIONS: Ongoing investigation is needed to improve our understanding of inherited susceptibility to disease in general and cancer predisposition syndromes, as this information has the potential to lead to the development of more precise and patient-specific counseling and surveillance strategies. The real-world adoption of new or improved technologies into clinical practice frequently requires medical decision-making in the absence of established understanding of gene-gene interactions. In the meantime, practitioners must be prepared to apply a rationale based on currently available knowledge to clinical decision-making. Current practice is evolving to rely heavily on clinical concordance with personal and family history in making specific therapeutic decisions.

Screening Children at Risk for Retinoblastoma: Consensus Report from the American Association of Ophthalmic Oncologists and Pathologists.

PURPOSE: To provide a set of surveillance guidelines for children at risk for development of retinoblastoma. DESIGN: Consensus panel. PARTICIPANTS: Expert panel of ophthalmic oncologists, pathologists, and geneticists. METHODS: A group of members of the American Association of Ophthalmic Oncologists and Pathologists (AAOOP) with support of the American Association for Pediatric Ophthalmology and Strabismus and the American Academy of Pediatrics (AAP) was convened. The panel included representative ophthalmic oncologists, pathologists, and geneticists from retinoblastoma referral centers located in various geographic regions who met and discussed screening approaches for retinoblastoma. A patient "at risk" was defined as a person with a family history of retinoblastoma in a parent, sibling, or first- or second-degree relative. MAIN OUTCOME MEASURES: Screening recommendations for children at risk for retinoblastoma. RESULTS: Consensus statement from the panel: (1) Dedicated ophthalmic screening is recommended for all children at risk for retinoblastoma above the population risk. (2) Frequency of examinations is adjusted on the basis of expected risk for RB1 mutation. (3) Genetic counseling and testing clarify the risk for retinoblastoma in children with a family history of the disease. (4) Examination schedules are stratified on the basis of high-, intermediate-, and low-risk children. (5) Children at high risk for retinoblastoma require more frequent screening, which may preferentially be examinations under anesthesia. CONCLUSIONS: Risk stratification including genetic testing and counseling serves as the basis for screening of children at elevated risk for development of retinoblastoma.

Vision Loss from Choroidal and Pituitary Metastases Secondary to Renal Cell Carcinoma: A Case Report.

A 62-year-old male with a history of metastatic clear cell renal cell carcinoma (ccRCC) presented with decreased vision to 20/50 in the left eye. Fundus examination revealed an elevated, amelanotic mass lesion in the superotemporal macula, without involvement of the central macula by subretinal fluid or tumour. Given incongruity between the fundus findings and the degree of visual impairment, visual field testing was obtained, revealing a bitemporal hemianopia. Magnetic resonance imaging demonstrated optic chiasm compression by a pituitary mass, which had previously been overlooked on computed tomography imaging. Biopsy confirmed metastatic ccRCC to the pituitary, which presented simultaneously with the presumed choroidal metastasis.

Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors.

PURPOSE: To evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in malignant iris melanomas and benign iris lesions. DESIGN: Cross-sectional observational clinical study. PARTICIPANTS: Patients with iris lesions and healthy volunteers. METHODS: Eyes were imaged using OCTA systems operating at 1050- and 840-nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanoma patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. MAIN OUTCOME MEASURES: OCT and OCTA images, qualitative evaluation of iris and tumor vasculature, and quantitative vessel density. RESULTS: One eye each of 8 normal volunteers and 9 patients with iris melanomas or benign iris lesions, including freckles, nevi, and an iris pigment epithelial (IPE) cyst, were imaged. The normal iris has radially oriented vessels within the stroma on OCTA. Penetration of flow signal in normal iris depended on iris color, with best penetration seen in light to moderately pigmented irides. Iris melanomas demonstrated tortuous and disorganized intratumoral vasculature. In 2 eyes with nevi there was no increased vascularity; in another, fine vascular loops were noted near an area of ectropion uveae. Iris freckles and the IPE cyst did not have intrinsic vascularity. The vessel density was significantly higher within iris melanomas (34.5%±9.8%, P < 0.05) than in benign iris nevi (8.0%±1.4%) or normal irides (8.0%±1.2%). Tumor regression after radiation therapy for melanomas was associated with decreased vessel density. OCTA at 1050 nm provided better visualization of tumor vasculature and penetration through thicker tumors than at 840 nm. But in very thick tumors and highly pigmented lesions even 1050-nm OCTA could not visualize their full thickness. Interpretable OCTA images were obtained in 82% of participants in whom imaging was attempted. CONCLUSIONS: This is the first demonstration of OCTA in iris tumors. OCTA may provide a dye-free, no-injection, cost-effective method for monitoring a variety of tumors, including iris melanocytic lesions, for growth and vascularity. This could be helpful in evaluating tumors for malignant transformation and response to treatment. Penetration of the OCT beam remains a limitation for highly pigmented tumors, as does the inability to image the entire iris in a single field.

CLINICOPATHOLOGIC CORRELATION OF RETINAL ANGIOMATOUS PROLIFERATION TREATED WITH RANIBIZUMAB.

PURPOSE: To describe histopathologic features of an eye with retinal angiomatous proliferation (RAP) secondary to age-related macular degeneration treated with serial ranibizumab injections and to correlate these findings with spectral domain optical coherence tomography. METHODS: Histopathologic features from serial sections through the globe of a 93-year-old man with age-related macular degeneration were studied and compared with spectral domain optical coherence tomography images obtained 7 weeks before his death. RESULTS: The pathologic correlate of ranibizumab-treated RAP was a circumscribed, branching paucicellular vascular complex extending from the inner plexiform layer to Bruch membrane. The histopathologic findings corresponded to an area of hyperreflectivity on spectral domain optical coherence tomography imaging, substantiating the reported tomographic appearance of RAP lesions. A frank anastomosis with choroidal or retinal vasculature was not seen in this treated RAP lesion. There was a lack of retinal pigment epithelium underlying the lesion in an area of retinal pigment epithelium detachment. The elastic portion of Bruch membrane appeared intact. Treatment with ranibizumab over an extended period of time may have been associated with a loss of cellularity of the RAP lesion. CONCLUSION: In a patient with ARMD extensively treated with ranibizumab, color fundus photography, fluorescein angiography and SD-OCT images of RAP correlated histopathologically with a paucicellular intraretinal vascular complex.

Panretinal handheld OCT angiography for pediatric retinal imaging.

Comprehensive visualization of retina morphology is essential in the diagnosis and management of retinal diseases in pediatric populations. Conventional imaging techniques often face challenges in effectively capturing the peripheral retina, primarily due to the limitations in current optical designs, which lack the necessary field of view to characterize the far periphery. To address this gap, our study introduces a novel ultra-widefield optical coherence tomography angiography (OCTA) system. This system, specifically tailored for pediatric applications, incorporates an ultrahigh-speed 800 kHz swept-source laser. The system's innovative design achieves a 140° field of view while maintaining excellent optical performance. Over the last 15 months, we have conducted 379 eye examinations on 96 babies using this system. It demonstrates marked efficacy in the diagnosis of retinopathy of prematurity, providing detailed and comprehensive peripheral retinal angiography. The capabilities of the ultra-widefield handheld OCTA system in enhancing the clarity and thoroughness of retina vascularization assessments have significantly improved the precision of diagnoses and the customization of treatment strategies. Our findings underscore the system's potential to advance pediatric ophthalmology and broaden the scope of retinal imaging.

Detection of neoplastic-immune hybrid cells with metastatic properties in uveal melanoma.

BACKGROUND: Uveal melanoma is the most common non-cutaneous melanoma and is an intraocular malignancy affecting nearly 7,000 individuals per year worldwide. Of these, approximately 50% will progress to metastatic disease for which there are currently no effective curative therapies. Despite advances in molecular profiling and metastatic stratification of uveal melanoma tumors, little is known regarding their underlying biology of metastasis. Our group has identified a disseminated neoplastic cell population characterized by co-expression of immune and melanoma proteins, circulating hybrid cells (hybrids), in patients with uveal melanoma. Compared to circulating tumor cells, which lack expression of immune proteins, hybrids are detected at an increased prevalence in peripheral blood and can be used as a non-invasive biomarker to predict metastatic progression. METHODS: To ascertain mechanisms underlying enhanced hybrid cell dissemination we identified hybrid cells within primary uveal melanoma tumors using single cell RNA sequencing (n = 8) and evaluated their gene expression and predicted ligand-receptor interactions in relation to other melanoma and immune cells within the primary tumor. We then verified expression of upregulated hybrid pathways within patient-matched tumor and peripheral blood hybrids (n = 4) using cyclic immunofluorescence and quantified their protein expression relative to other non-hybrid tumor and disseminated tumor cells. RESULTS: Among the top upregulated genes and pathways in hybrid cells were those involved in enhanced cell motility and cytoskeletal rearrangement, immune evasion, and altered cellular metabolism. In patient-matched tumor and peripheral blood, we verified gene expression by examining concordant protein expression for each pathway category: TMSB10 (cell motility), CD74 (immune evasion) and GPX1 (metabolism). Both TMSB10 and GPX1 were expressed on significantly higher numbers of disseminated hybrid cells compared to circulating tumor cells, and CD74 and GPX1 were expressed on more disseminated hybrids than tumor-resident hybrids. Lastly, we identified that hybrid cells express ligand-receptor signaling pathways implicated in promoting metastasis including GAS6-AXL, CXCL12-CXCR4, LGALS9-P4HB and IGF1-IGFR1. CONCLUSION: These findings highlight the importance of TMSB10, GPX1 and CD74 for successful hybrid cell dissemination and survival in circulation. Our results contribute to the understanding of uveal melanoma tumor progression and interactions between tumor cells and immune cells in the tumor microenvironment that may promote metastasis.

15-Gene Expression Profile and PRAME as Integrated Prognostic Test for Uveal Melanoma: First Report of Collaborative Ocular Oncology Group Study No. 2 (COOG2.1).

PURPOSEValidated and accurate prognostic testing is critical for precision medicine in uveal melanoma (UM). Our aims were to (1) prospectively validate an integrated prognostic classifier combining a 15-gene expression profile (15-GEP) and PRAME RNA expression and (2) identify clinical variables that enhance the prognostic accuracy of the 15-GEP/PRAME classifier.MATERIALS AND METHODSThis study included 1,577 patients with UM of the choroid and/or ciliary body who were enrolled in the Collaborative Ocular Oncology Group Study Number 2 (COOG2) and prospectively monitored across 26 North American centers. Test results for 15-GEP (class 1 or class 2) and PRAME expression status (negative or positive) were available for all patients. The primary end point was metastasis-free survival (MFS).RESULTS15-GEP was class 1 in 1,082 (68.6%) and class 2 in 495 (31.4%) patients. PRAME status was negative in 1,106 (70.1%) and positive in 471 (29.9%) patients. Five-year MFS was 95.6% (95% CI, 93.9 to 97.4) for class 1/PRAME(-), 80.6% (95% CI, 73.9 to 87.9) for class 1/PRAME(+), 58.3% (95% CI, 51.1 to 66.4) for class 2/PRAME(-), and 44.8% (95% CI, 37.9 to 52.8) for class 2/PRAME(+). By multivariable Cox proportional hazards analysis, 15-GEP was the most important independent predictor of MFS (hazard ratio [HR], 5.95 [95% CI, 4.43 to 7.99]; P < .001), followed by PRAME status (HR, 1.82 [95% CI, 1.42 to 2.33]; P < .001). The only clinical variable demonstrating additional prognostic value was tumor diameter.CONCLUSIONIn the largest prospective multicenter prognostic biomarker study performed to date in UM to our knowledge, the COOG2 study validated the superior prognostic accuracy of the integrated 15-GEP/PRAME classifier over 15-GEP alone and clinical prognostic variables. Tumor diameter was found to be the only clinical variable to provide additional prognostic information. This prognostic classifier provides an advanced resource for risk-adjusted metastatic surveillance and adjuvant trial stratification in patients with UM.

Differentiating MYCN-amplified RB1 wild-type retinoblastoma from biallelic RB1 mutant retinoblastoma using MR-based radiomics: a retrospective multicenter case-control study.

MYCN-amplified RB1 wild-type (MYCNampRB1+/+) retinoblastoma is a rare and aggressive subtype, often resistant to standard therapies. Identifying unique MRI features is crucial for diagnosing this subtype, as biopsy is not recommended. This study aimed to differentiate MYCNampRB1+/+ from the most prevalent RB1-/- retinoblastoma using pretreatment MRI and radiomics. Ninety-eight unilateral retinoblastoma patients (19 MYCN cases and 79 matched controls) were included. Tumors on T2-weighted MR images were manually delineated and validated by experienced radiologists. Radiomics analysis extracted 120 features per tumor. Several combinations of feature selection methods, oversampling techniques and machine learning (ML) classifiers were evaluated in a repeated fivefold cross-validation machine learning pipeline to yield the best-performing prediction model for MYCN. The best model used univariate feature selection, data oversampling (duplicating MYCN cases), and logistic regression classifier, achieving a mean AUC of 0.78 (SD 0.12). SHAP analysis highlighted lower sphericity, higher flatness, and greater gray-level heterogeneity as predictive for MYCNampRB1+/+ status, yielding an AUC of 0.81 (SD 0.11). This study shows the potential of MRI-based radiomics to distinguish MYCNampRB1+/+ and RB1-/- retinoblastoma subtypes.

Increased Number and Severity of Open Globe Injuries during COVID-19 Stay-at-home Orders.

PURPOSE: To evaluate the occurrence and outcome of open globe injury during state-mandated COVID-19 stay-at-home orders compared to historical averages at a tertiary medical center in Portland, Oregon. METHODS: Open globe injury between January 1, 2015 and December 31, 2020 was identified using relevant procedure codes. The number of injuries, mechanism of trauma, and short-term outcomes of globes repaired during the study period of March 23, 2020 to July 6, 2020 when stay-at-home orders were in effect were compared to a cohort from the same 15-week time frame in 2015-2019. We also evaluated injuries occurring throughout 2020 as compared to the prior 5 years. RESULTS: 263 consecutive open globe injuries were identified between January 2015 and December 2020. While Oregon's stay-at-home orders were in effect, we observed a significant increase in the number of open globe injuries treated compared to the prior 5 years (p = .004). Twenty-four cases identified during the study period represent a 2-fold increase over the 2015-2019 average of 11.8 globe repairs during the same 15-week time period. Visual acuity < 20/200 at 6 months (p = .008) and secondary enucleation (p < .001) were more frequent during stay-at-home orders, and severity of injury as calculated by the Ocular Trauma Scores (OTS) was higher. Time-to-repair was similar between the two cohorts. CONCLUSION: At our center, there was an increased number and severity of open globe injury during the period of mandatory COVID-19 stay-at-home orders. Visual acuity outcomes and risk for secondary enucleation were poorer compared to the reference cohort.Abbreviations: Ocular Trauma Score (OTS), Open globe injury (OGI), Emergency department (ED), Oregon Health and Science University (OHSU).

Psychometric Results of a New Patient-Reported Outcome Measure for Uveal Melanoma Post-Brachytherapy Treatment: The PROM-UM.

The objective of this study was to evaluate the psychometric properties of a new patient-reported outcome instrument intended for use with patients who have undergone brachytherapy for uveal melanoma (PROM-UM). Classical test theory and item response theory were used to evaluate the performance of individual items and domains. A convenience sample of 439 participants who had undergone brachytherapy for uveal melanoma from one of three North American ocular oncology treatment centers were included in this cross-sectional study. Exploratory factor analysis identified three domains which were labelled "Symptom Impairment", "Worry", and "Discomfort". The acceptability of the instrument was supported by little missing data (range = 0.00-1.14%) and low maximum endorsement (range = 0.00-1.82%). Item-total (range = 0.68-0.85) and inter-item (range = 0.74-0.80) correlations indicated acceptable reliability. Discrimination and difficulty were assessed using item response theory. Items in all three domains indicated moderate to very high discrimination (range = 1.00-4.10). Two items in the Symptom Impairment domain were too difficult to measure. Response ranges in the other two domains demonstrated acceptable difficulty. These results from the study indicate that this new patient-reported outcome instrument can be used with patients treated with brachytherapy for uveal melanoma. Providers could use this instrument to help inform post-treatment management.

PSEUDOPANUVEITIS AS A HARBINGER FOR SYSTEMIC LEUKEMIA RECURRENCE.

PURPOSE: To describe a patient with a history of pre-B-cell acute lymphoblastic leukemia in remission, who developed recurrent alternating intraocular leukemia manifesting with pseudohypopyon, uveal mass, and serous retinal detachment. In multiple instances, this constellation of ocular findings preceded systemic leukemia recurrence. METHOD: Case report. RESULTS: A 29-year-old man with a history of pre-B-cell acute lymphoblastic leukemia, in remission after a hematopoietic stem cell transplant, presented with pseudohypopyon, uveal lesions, and serous retinal detachment of the right eye. Comprehensive workup for infectious and inflammatory etiologies was unremarkable, and a bone marrow biopsy revealed systemic recurrence of leukemia. One year later, while again in remission, the patient developed a pseudohypopyon, uveal mass, and serous retinal detachment of the other eye. Repeat bone marrow biopsy showed impending leukemia relapse, which occurred 1 month later. Orbital radiation resulted in complete ocular resolution. CONCLUSION: The constellation of pseudohypopyon, serous retinal detachment, and uveal mass (pseudopanuveitis) should be recognized as a harbinger for systemic pre-B ALL recurrence.

Analysis of uveal melanoma scRNA sequencing data identifies neoplastic-immune hybrid cells that exhibit metastatic potential.

Uveal melanoma (UM) is the most common non-cutaneous melanoma and is an intraocular malignancy that affects nearly 7,000 individuals per year worldwide. Of these, nearly 50% will progress to metastatic disease for which there are currently no effective therapies. Despite advances in the molecular profiling and metastatic stratification of class 1 and 2 UM tumors, little is known regarding the underlying biology of UM metastasis. Our group has identified a disseminated tumor cell population characterized by co-expression of immune and melanoma proteins, (circulating hybrid cells (CHCs), in patients with UM. Compared to circulating tumor cells, CHCs are detected at an increased prevalence in peripheral blood and can be used as a non-invasive biomarker to predict metastatic progression. To identify mechanisms underlying enhanced hybrid cell dissemination we sought to identify hybrid cells within a primary UM single cell RNA-seq dataset. Using rigorous doublet discrimination approaches, we identified UM hybrids and evaluated their gene expression, predicted ligand-receptor status, and cell-cell communication state in relation to other melanoma and immune cells within the primary tumor. We identified several genes and pathways upregulated in hybrid cells, including those involved in enhancing cell motility and cytoskeleton rearrangement, evading immune detection, and altering cellular metabolism. In addition, we identified that hybrid cells express ligand-receptor signaling pathways implicated in promoting cancer metastasis including IGF1-IGFR1, GAS6-AXL, LGALS9-P4HB, APP-CD74 and CXCL12-CXCR4. These results contribute to our understanding of tumor progression and interactions between tumor cells and immune cells in the UM microenvironment that may promote metastasis.

Panretinal Optical Coherence Tomography.

We introduce a new concept of panoramic retinal (panretinal) optical coherence tomography (OCT) imaging system with a 140° field of view (FOV). To achieve this unprecedented FOV, a contact imaging approach was used which enabled faster, more efficient, and quantitative retinal imaging with measurement of axial eye length. The utilization of the handheld panretinal OCT imaging system could allow earlier recognition of peripheral retinal disease and prevent permanent vision loss. In addition, adequate visualization of the peripheral retina has a great potential for better understanding disease mechanisms regarding the periphery. To the best of our knowledge, the panretinal OCT imaging system presented in this manuscript has the widest FOV among all the retina OCT imaging systems and offers significant values in both clinical ophthalmology and basic vision science.

A Multicenter Analysis of Nucleic Acid Quantification Using Aqueous Humor Liquid Biopsy in Retinoblastoma: Implications for Clinical Testing.

Purpose: Retinoblastoma (RB) is most often diagnosed with clinical features and not diagnosed with tumor biopsy. This study describes tumor-derived analyte concentrations from aqueous humor (AH) liquid biopsy and its use in clinical assays. Design: Case series study. Participants: Sixty-two RB eyes from 55 children and 14 control eyes from 12 children from 4 medical centers. Methods: This study included 128 RB AH samples including: diagnostic (DX) samples, samples from eyes undergoing treatment (TX), samples after completing treatment (END), and during bevacizumab injection for radiation therapy after completing RB treatment (BEV). Fourteen-control AH were analyzed for unprocessed analytes (double-stranded DNA [dsDNA], single-stranded DNA [ssDNA], micro-RNA [miRNA], RNA, and protein) with Qubit fluorescence assays. Double-stranded DNA from 2 RB AH samples underwent low-pass whole-genome sequencing to detect somatic copy number alterations. Logistic regression was used to predict disease burden given analyte concentrations. Main Outcome Measures: Unprocessed analyte (dsDNA, ssDNA, miRNA, RNA and protein) concentrations. Results: Results revealed dsDNA, ssDNA, miRNA, and proteins, but not RNA, were quantifiable in most samples (up to 98%) with Qubit fluorescence assays. Median dsDNA concentration was significantly higher in DX (3.08 ng/µl) compared to TX (0.18 ng/µl; P < 0.0001) at an order of 17 times greater and 20 times greater than END samples (0.15 ng/µl; P = 0.001). Using logistic regression, nucleic acid concentrations were useful in predicting higher versus lower RB disease burden. Retinoblastoma somatic copy number alterations were identified in a TX, but not in a BEV sample, indicating the correlation with RB activity. Conclusions: Aqueous humor liquid biopsy in RB is a high-yield source of dsDNA, ssDNA, miRNA, and protein. Diagnostic samples are most useful for RB 1 gene mutational analyses. Genomic analysis may be more informative of tumor activity status than quantification alone and can be performed even with smaller analyte concentrations obtained from TX samples. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

Detection of neoplastic-immune hybrid cells with metastatic properties in uveal melanoma.

Background: Uveal melanoma is the most common non-cutaneous melanoma and is an intraocular malignancy affecting nearly 7,000 individuals per year worldwide. Of these, approximately 50% will progress to metastatic disease for which there are currently no effective therapies. Despite advances in molecular profiling and metastatic stratification of uveal melanoma tumors, little is known regarding their underlying biology of metastasis. Our group has identified a disseminated neoplastic cell population characterized by co-expression of immune and melanoma proteins, circulating hybrid cells (hybrids), in patients with uveal melanoma. Compared to circulating tumor cells, which lack expression of immune proteins, hybrids are detected at an increased prevalence in peripheral blood and can be used as a non-invasive biomarker to predict metastatic progression. Methods: To ascertain mechanisms underlying enhanced hybrid cell dissemination we identified hybrid cells within primary uveal melanoma tumors using single cell RNA sequencing and evaluated their gene expression and predicted ligand-receptor interactions in relation to other melanoma and immune cells within the primary tumor. We then verified expression of upregulated hybrid pathways within patient-matched tumor and peripheral blood hybrids using cyclic immunofluorescence and quantified their protein expression relative to other non-hybrid tumor and disseminated tumor cells. Results: Among the top upregulated genes and pathways in hybrid cells were those involved in enhanced cell motility and cytoskeletal rearrangement, immune evasion, and altered cellular metabolism. In patient-matched tumor and peripheral blood, we verified gene expression by examining concordant protein expression for each pathway category: TMSB10 (cell motility), CD74 (immune evasion) and GPX1 (metabolism). Both TMSB10 and GPX1 were expressed on significantly higher numbers of disseminated hybrid cells compared to circulating tumor cells, and CD74 and GPX1 were expressed on more disseminated hybrids than tumor-resident hybrids. Lastly, we identified that hybrid cells express ligand-receptor signaling pathways implicated in promoting metastasis including GAS6-AXL, CXCL12-CXCR4, LGALS9-P4HB and IGF1-IGFR1. Conclusion: These findings highlight the importance of TMSB10, GPX1 and CD74 for successful hybrid cell dissemination and survival in circulation. Our results contribute to the understanding of uveal melanoma tumor progression and interactions between tumor cells and immune cells in the tumor microenvironment that may promote metastasis.

Treatment of Aggressive Retinal Astrocytic Hamartoma with Oral Mechanistic Target of Rapamycin Inhibition.

PURPOSE: To describe the clinical course and outcomes of aggressive retinal astrocytic hamartoma (RAH) treated with oral mechanistic target of rapamycin inhibitors (mTORis). DESIGN: A retrospective clinical case series. PARTICIPANTS: Five patients with genetically confirmed tuberous sclerosis complex and visually significant RAH due to tumor growth or exudation. METHODS: In this retrospective clinical case series, a review of electronic medical records was performed to determine baseline and follow-up ophthalmic examination characteristics, along with ancillary imaging findings, in patients receiving off-label treatment with either oral sirolimus or everolimus for symptomatic RAH. MAIN OUTCOME MEASURES: Visual acuity, change in tumor size, degree of exudation, and adverse effects of the mTORis were evaluated. RESULTS: The 5 patients in this series ranged in age from 8 months to 54 years. Four were treated with sirolimus, and 1 received everolimus. In all the cases, the tumor height was stable or decreased after the treatment (median follow-up duration, 39 months; range, 11-73 months). Exudation improved after the treatment in all the cases. In an 8-month-old infant, frequent upper respiratory tract infections prompted the cessation of treatment. In 1 patient, the mTORi was temporarily withheld because of elevated liver enzyme levels. No other significant adverse effects were noted. CONCLUSIONS: Sirolimus and everolimus should be considered in the management of vision-threatening RAH, particularly in the setting of exudative and rapidly growing tumors. Four of the 5 patients in this series tolerated the oral mTORi and continued with the therapy. There were no serious complications.