Lehman, Julia S.

Abstract One of the greatest barriers to curative treatment of neuroblastoma is its frequent metastatic outgrowth prior to diagnosis, especially in cases driven by amplification of the MYCN oncogene. However, only a limited number of regulatory proteins that contribute to this complex MYCN-mediated process have been elucidated. Here we show that the growth arrest-specific 7 (GAS7) gene, located at chromosome band 17p13.1, is preferentially deleted in high-risk MYCN-driven neuroblastoma. GAS7 expression was also suppressed in MYCN-amplified neuroblastoma lacking 17p deletion. GAS7 deficiency led to accelerated metastasis in both zebrafish and mammalian models of neuroblastoma with overexpression or amplification of MYCN. Analysis of expression profiles and the ultrastructure of zebrafish neuroblastoma tumors with MYCN overexpression identified that GAS7 deficiency led to (i) downregulation of genes involved in cell–cell interaction, (ii) loss of contact among tumor cells as critical determinants of accelerated metastasis, and (iii) increased levels of MYCN protein. These results provide the first genetic evidence that GAS7 depletion is a critical early step in the cascade of events culminating in neuroblastoma metastasis in the context of MYCN overexpression. Significance: Heterozygous deletion or MYCN-mediated repression of GAS7 in neuroblastoma releases an important brake on tumor cell dispersion and migration to distant sites, providing a novel mechanism underlying tumor metastasis in MYCN-driven neuroblastoma. See related commentary by Menard, p. 2815

Abstract Background: The objective of the study was to explore disease pathways activated in the inflammatory foci of skin lesions in cutaneous lupus erythematosus (CLE) and dermatomyositis (DM). Methods: Skin biopsies acquired from active CLE and DM lesions, patient (PC) and also healthy controls (HC) were investigated. Biopsy sections were examined by a pathologist and inflammatory foci were laser micro-dissected, captured and proteins within captured tissue were detected in a hypothesis free manner by mass-spectrometry. Protein pathway analysis was performed by string-db.org platform. Findings of interest were confirmed by immunohistochemistry (IHC).Results: Proteome investigation identified interleukin (IL)-16 to be the only detectable and abundant cytokine differentially expressed in CLE compared to DM. Caspase-3, enzyme that cleaves IL-16 into its active form, was detected in low levels. Significantly higher proportion of IL-16 and Caspase-3 positive cells were identified in CLE lesions in comparison to DM, PC and HC. Interferon-regulated proteins (IRP) were abundant in both CLE and DM. Proteomic results indicate more abundant complement deposition in CLE skin lesions. Conclusions: Using hypothesis free mass-spectrometry investigation of CLE inflammatory infiltrates, we identified that IL-16 is the only detectable and highly abundant cytokine, while IRP was a common feature of both CLE and DM. IHC confirmed high expression of IL-16 and caspase-3 in CLE. Our novel molecular findings indicate that IL-16 detection could be useful in differential diagnostics between the two conditions that can display similar histopathological appearance. Potentially, IL-16 could be of interest as a future therapeutic target for CLE.

AbstractBackgroundThe histopathological diagnosis of MF is challenging, and there is significant overlap with benign inflammatory processes. Clinical features may be relevant in the assessment of skin biopsies.MethodsWe provided photomicrographs to board‐certified dermatopathologists and one hematopathologist with and without accompanying clinical photographs and assessed accuracy and confidence in diagnosing MF.ResultsWe found that access to clinical photographs improved diagnostic accuracy in both MF and non‐MF (distractors); the degree of improvement was significantly higher in the non‐MF/distractor category. Across all categories, diagnostic confidence level was higher when clinical images were available.ConclusionThese findings suggest that clinical images are useful in making an accurate diagnosis of MF, and may be particularly helpful in ruling it out when an inflammatory disorder is clinically suspected.

AbstractBackgroundTo retrospectively review the outcomes of two rare cutaneous diseases, Stevens‐Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), and to question the practice of averaging the mortality rate on the assumption that they are one disease.MethodsA retrospective chart review of all patients diagnosed with SJS and TEN by a dermatologist between January 1, 2000, and January 1, 2020, at our institution was performed. Seventy‐one patients were identified (21 pediatric and 50 adults). Pathology slides from 32 adult patients (64%) were evaluated by a blinded board‐certified dermatopathologist.ResultsOf the adult patients, 31 had SJS, two had SJS‐TEN overlap, and 17 had TEN. All 21 patients in the pediatric group were diagnosed with SJS mainly caused by Mycoplasma. Mortality rates were 6.5% for SJS among adults and 35.3% for TEN. Chemotherapy‐induced TEN is a trigger with 50% mortality.ConclusionsSJS was more common in adults and pediatric cases than TEN (3:1) and had a much better prognosis and outcome. Combining and averaging the mortality rates of TEN and SJS are not advised as SJS is mainly a mucocutaneous disorder with good prognosis versus TEN, a systemic toxicity of multiple organs with deep skin detachment.

e22024 Background: Disease surveillance in high risk melanoma patients using PET/CT is recommended every 6 months, an algorithm that is extremely expensive and often difficult to access. Biomarkers capable of detecting recurrence and low volume metastasis have application in tools to improve the cost effectiveness of surveillance. Towards this long term goal, our aim was to discover melanoma-specific methylated DNA markers (MDMs). Methods: Candidate MDMs were identified by reduced representation bisulfite sequencing of selected age- and sex-balanced snap frozen metastatic melanoma, benign control skin and white blood cells. Sequences were filtered for highest methylation difference, lowest control methylation background ( < 1%), and highest discrimination by variance inflated logistic regression. Using formalin-fixed tissues, the top 32 MDMs were further evaluated in metastatic melanoma from 35 patients, primary melanoma from 26 patients, and 73 control samples (47 benign precursor lesions or normal skin, and 26 healthy buffy coat samples to assess for background DNA in circulation). Candidate markers were blindly assayed by quantitative methylation specific PCR. After normalization by within sample ACTB level, random forest modeling with cross-validation identified marker combinations with greatest predictive accuracy. Results: On receiver operator characteristics analyses of individual marker candidates, areas under the curve (AUCs) ranged from 0.43 to 0.97. Median AUC was 0.835. At 100% specificity, a cross-validated panel of five MDMs (see Table), yielded a sensitivity of 33/35 cases (94.3%; 95% CI, 86.6-100%) for metastatic melanoma and 22/26 cases (84.6%; 95% CI, 70.7-98.5%) for primary melanoma. Furthermore, none of the 5 markers were detected in normal buffy coat samples. Conclusions: A panel of five novel MDMs assayed on tissue and undetectable in normal buffy coat achieves very high discrimination between melanoma and benign control tissues. This panel can be assessed in blood or other bodily fluids for application in melanoma surveillance. [Table: see text]

PURPOSEMore than 80% of patients who undergo sentinel lymph node (SLN) biopsy have no nodal metastasis. Here, we describe a model that combines clinicopathologic and molecular variables to identify patients with thin- and intermediate-thickness melanomas who may forgo the SLN biopsy procedure because of their low risk of nodal metastasis.PATIENTS AND METHODSGenes with functional roles in melanoma metastasis were discovered by analysis of next-generation sequencing data and case-control studies. We then used polymerase chain reaction to quantify gene expression in diagnostic biopsy tissue across a prospectively designed archival cohort of 754 consecutive thin- and intermediate-thickness primary cutaneous melanomas. Outcome of interest was SLN biopsy metastasis within 90 days of melanoma diagnosis. A penalized maximum likelihood estimation algorithm was used to train logistic regression models in a repeated cross-validation scheme to predict the presence of SLN metastasis from molecular, clinical, and histologic variables.RESULTSExpression of genes with roles in epithelial-to-mesenchymal transition (glia-derived nexin, growth differentiation factor 15, integrin-β3, interleukin 8, lysyl oxidase homolog 4, transforming growth factor-β receptor type 1, and tissue-type plasminogen activator) and melanosome function (melanoma antigen recognized by T cells 1) were associated with SLN metastasis. The predictive ability of a model that only considered clinicopathologic or gene expression variables was outperformed by a model that included molecular variables in combination with the clinicopathologic predictors Breslow thickness and patient age (area under the receiver operating characteristic curve, 0.82; 95% CI, 0.78 to 0.86; SLN biopsy reduction rate, 42%; negative predictive value, 96%).CONCLUSIONA combined model that included clinicopathologic and gene expression variables improved the identification of patients with melanoma who may forgo the SLN biopsy procedure because of their low risk of nodal metastasis.