Angiomyolipomatous Lesions of the Nasal Cavity (Sinonasal Angioleiomyoma with Adipocytic Differentiation): A Multi-Institutional Immunohistochemical and Molecular Study.

PURPOSE: Mesenchymal neoplasms composed of vascular, smooth muscle, and adipocytic components are uncommon in the nasal cavity. While angioleiomyoma (AL) is a smooth muscle tumor in the Head & Neck WHO classification, it is considered of pericytic origin in the Skin as well as Soft Tissue and Bone classifications. For nasal AL with an adipocytic component, the terms AL with adipocytic differentiation and angiomyolipoma (AML) have been applied, among others. AML is a type of perivascular epithelioid cell tumor (PEComa), most often arising in the kidney, sometimes associated with the tuberous sclerosis complex (TSC). It is uncertain whether nasal cavity AML and AL are best considered hamartomas or neoplasms, as their genetics are largely unexplored. METHODS: We performed a multi-institutional retrospective study of nasal cavity mesenchymal lesions. Patient demographics, clinical histories, and histologic and immunohistochemical findings were collected. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tissue and analyzed by SNP-based chromosomal microarray, targeted RNA fusion sequencing, and whole-exome sequencing. RESULTS: Fifteen lesions (3-42 mm) were identified, predominantly in male (87%) patients with a median age of 60. Patients typically presented with obstructive symptoms, and none had a history of TSC. One AL was a recurrence from six years prior; 11 cases showed no recurrence (median 4.7 years, range: 0.88-12.4). Morphologically, 11 AML contained 30-80% smooth muscle, 10-25% vasculature, and 2-60% adipose tissue, while four AL contained 70-80% smooth muscle and 20-30% vasculature. Other histologic observations included ulceration, thrombosis, inflammation, myxoid change, senescent nuclei, and extramedullary hematopoiesis; no well-developed epithelioid cell morphology was identified. Immunohistochemically, all cases were positive for smooth muscle markers (actin, desmin, and/or caldesmon) and negative for melanocytic markers. Molecular analysis revealed loss of 3p and 11q in a single AML. No other known pathogenic copy number or molecular alterations were seen, including in TSC1/2, TFE3, or NOTCH2. CONCLUSION: Nasal cavity AML lacks morphologic, immunophenotypic, and genetic features of PEComa family AML. The significant histologic overlap between nasal AML and AL without distinguishing molecular features in either entity suggests "sinonasal angioleiomyoma with adipocytic differentiation" may be the most appropriate terminology for hybrid vascular and smooth muscle lesions containing adipocytic components.

Comparative Analysis of MYB Expression by Immunohistochemistry and RNA Sequencing in Clinical Gene Fusion Detection in Adenoid Cystic Carcinoma.

PURPOSE: MYB has been shown to play a central role in oncogenesis in a majority of adenoid cystic carcinomas (ACC). Testing for MYB expression via immunohistochemistry (IHC) or testing for the MYB gene fusion by next-generation sequencing (NGS) have become useful tools for the diagnosis of ACC. In addition, detection of MYB expression may have implications for patient management. METHODS: A cohort of 35 ACC cases was identified from the archival pathology files of the Massachusetts General Hospital. Cases were tested for MYB expression using a panel of 4 different commercially available MYB antibodies and scored using a modified Allred system. RNA-based NGS for MYB gene fusion detection was also performed. RESULTS: Among 4 different MYB antibodies, the sensitivity for MYB detection ranged from 26 to 97%. When a 30% threshold for determination of MYB immunohistochemical positivity was used, the AB_10900735 IHC clone showed the maximum sensitivity (97%). RNA sequencing revealed 19 (54%) cases positive for MYB fusions, and expression analysis derived from the sequencing data confirmed a significant association between MYB expression and fusion status (p = 0.036). Although less sensitive, the AB_778878 MYB clone showed a significant positive association between IHC staining and MYB RNA expression (R2 = 0.15, p = 0.023). CONCLUSION: The detection of MYB expression using immunohistochemistry varies significantly depending on the antibody used. Comparison with MYB fusion and transcription levels, as determined by NGS, reveals that MYB has a complex relationship between genetic alterations, transcript levels, and protein abundance.

Angiomyolipomatous Lesions of the Nasal Cavity (Sinonasal Angioleiomyoma with Adipocytic Differentiation): A Multi-Institutional Immunohistochemical and Molecular Study.

Purpose: Mesenchymal neoplasms composed of vascular, smooth muscle, and adipocytic components are uncommon in the nasal cavity. While angioleiomyoma (AL) is a smooth muscle tumor in the Head & Neck WHO classification, it is considered of pericytic origin in the Skin as well as Soft Tissue and Bone classifications. For nasal AL with an adipocytic component, the terms AL with adipocytic differentiation and angiomyolipoma (AML) have been applied, among others. AML is a type of perivascular epithelioid cell tumor (PEComa), most often arising in the kidney, sometimes associated with the tuberous sclerosis complex (TSC). It is uncertain whether nasal cavity AML and AL are best considered hamartomas or neoplasms, as their genetics are largely unexplored. Methods: We performed a multi-institutional retrospective study of nasal cavity mesenchymal lesions. Patient demographics, clinical histories, and histologic and immunohistochemical findings were collected. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tissue and analyzed by SNP-based chromosomal microarray, targeted RNA fusion sequencing, and whole-exome sequencing. Results: Fifteen lesions (3 to 42 mm) were identified predominantly in male (87%) patients with a median age of 60. Patients typically presented with obstructive symptoms, and none had a history of TSC. One AL was a recurrence from six years prior; 11 cases showed no recurrence (median 4.7 years, range: 0.88-12.4). Morphologically, 11 AMLs contained 30-80% smooth muscle, 10-25% vasculature, and 2-60% adipose tissue, while four ALs contained 70-80% smooth muscle and 20-30% vasculature. Other histologic observations included surface ulceration, vascular thrombosis, chronic inflammation, and myxoid change; no well-developed epithelioid cell morphology was identified. Immunohistochemically, all cases were positive for smooth muscle markers (actin and/or desmin) and negative for melanocytic markers. Molecular analysis revealed loss of 3p and 11q in a single AML. No other known pathogenic copy number or molecular alterations were seen, including in TSC1/2, TFE3, or NOTCH2. Conclusion: Nasal cavity AML lacks morphologic, immunophenotypic, and genetic features of PEComa family AMLs. The significant histologic overlap between nasal AML and AL without distinguishing molecular features in either entity suggests "sinonasal angioleiomyoma with adipocytic differentiation" may be the most appropriate terminology for hybrid vascular and smooth muscle lesions containing adipocytic components.

Detection of RAS p.Q61R by Immunohistochemistry in Practice: A Clinicopathologic Study of 217 Thyroid Nodules with Molecular Correlates.

RAS p.Q61R is the most prevalent hot-spot mutation in RAS and RAS-like mutated thyroid nodules. A few studies evaluated RAS p.Q61R by immunohistochemistry (RASQ61R-IHC). We performed a retrospective study of an institutional cohort of 150 patients with 217 thyroid lesions tested for RASQ61R-IHC, including clinical, cytologic and molecular data. RASQ61R-IHC was performed on 217 nodules (18% positive, 80% negative, and 2% equivocal). RAS p.Q61R was identified in 76% (n = 42), followed by RAS p.Q61K (15%; n = 8), and RAS p.G13R (5%; n = 3). NRAS p.Q61R isoform was the most common (44%; n = 15), followed by NRAS p.Q61K (17%; n = 6), KRAS p.Q61R (12%; n = 4), HRAS p.Q61R (12%; n = 4), HRAS p.Q61K (6%; n = 2), HRAS p.G13R (6%; n = 2), and NRAS p.G13R (3%; n = 1). RASQ61R-IHC was positive in 47% of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP; 17/36), 22% of follicular thyroid carcinomas (FTC; 5/23), 10% of follicular thyroid adenomas (FTA; 4/40), and 8% of papillary thyroid carcinomas (PTC; 9/112). Of PTC studied (n = 112), invasive encapsulated follicular variant (IEFVPTC; n = 16) was the only subtype with positive RASQ61R-IHC (56%; 9/16). Overall, 31% of RAS-mutated nodules were carcinomas (17/54); and of the carcinomas, 94% (16/17) were low-risk per American Thyroid Associated (ATA) criteria, with only a single case (6%; 1/17) considered ATA high-risk. No RAS-mutated tumors recurred, and none showed local or distant metastasis (with a follow-up of 0-10 months). We found that most RAS-mutated tumors are low-grade neoplasms. RASQ61R-IHC is a quick, cost-effective, and reliable way to detect RAS p.Q61R in follicular-patterned thyroid neoplasia and, when malignant, guide surveillance.

FGFR Alterations in Thyroid Carcinoma: A Novel Class of Primary Drivers with Significant Therapeutic Implications and Secondary Molecular Events Potentially Mediating Resistance in Thyroid Malignancy.

Background: Diagnostic classification of thyroid malignancy is primarily accomplished through examination of histomorphological features and may be substantiated and clarified by molecular data. Individual molecular drivers show relatively robust and specific associations with histological subtypes of thyroid malignancy, including BRAF sequence variants and kinase gene fusions in papillary thyroid carcinoma, predominantly RAS variants in follicular-patterned neoplasia, and additional "late" mutations affecting TERT promoter, TP53, and the PI3K/AKT/PTEN pathway in high-grade malignancies. Given the oncogenic role of FGFR, particularly FGFR1-3, the goal of this study was to explore the role of FGFR in thyroid carcinoma biology. Methods: We completed a multicenter retrospective observational study for thyroid carcinomas with pathogenic alterations in the FGFR gene family. We performed this study by querying the molecular data accumulated for thyroid carcinomas from each center. Results: Overall, 5030 sequenced thyroid malignancies were reviewed, yielding 17 tumors with FGFR alterations, including 11 where FGFR was the primary molecular driver and 6 where FGFR was a secondary pathogenic alteration, with a subset for which there was available clinical follow-up data. Of the 11 carcinomas with an FGFR driver, 9 were gene fusions involving FGFR2:VCL (4 tumors), TG::FGFR1 (3 tumors), FGFR2::CIT, and FGFR2::SHTN1, and the remaining 2 were driven by FGFR1 amplification. In the 6 tumors where a canonical driver of thyroid neoplasia was present (5 cases) or no clear primary driver was detected (1 case), sequencing detected secondary FGFR2 p.W290C, p.Y375C, and p.N549K, as well as FGFR1 p.N546K in the respective tyrosine kinase domains, some at subclonal variant allele frequencies. Conclusions: This study presents the first description of a collection of thyroid carcinomas grouped by primary driver alterations in FGFR, as well as a cohort of thyroid tumors with secondary alterations that potentially lead to tumor progression or resistance to targeted therapy. Given the availability of small molecular inhibitors targeting oncogenic FGFR, this study emphasizes the significant implications for patients from identification of FGFR alterations as they are currently under-recognized in the literature and, most importantly, have potential novel treatment options.

Utility of an anchored multiplex polymerase chain reaction-based fusion assay for diagnosis of soft tissue tumors in cytology.

BACKGROUND: Fine-needle aspiration specimens from soft tissue tumors are complicated by lack of tissue architecture and limited material for ancillary testing. There are little data on the feasibility of next-generation sequencing techniques for fusion detection on soft tissue cytology specimens. This study explored the role of an anchored multiplex polymerase chain reaction (PCR)-based gene fusion assay in aiding the diagnosis of mesenchymal neoplasms on cytology samples. METHODS: The laboratory information system was queried for cytology specimens that had undergone testing by anchored multiplex PCR. After exclusion of epithelial and hematolymphoid neoplasms, clinical and pathologic information was collected on the remaining cases. RESULTS: There were 1609 cytology specimens tested with anchored multiplex PCR. Of these, 48 (3%) were cytology specimens from mesenchymal tumors. Anchored multiplex PCR was positive for a reportable fusion transcript in 14 of 48 cases (29%); there was no fusion detected in 32 cases (67%), and there was insufficient tissue for analysis in two cases (4%). The detectable fusion partners included ALK (n = 4), STAT6 (n = 4), EWSR1 (n = 3), and one each of SS18, YAP1, and PHF1. Of the cases in which a fusion partner was detected, eight of 14 were disease-defining on cytology preparation, and six of 14 provided molecular confirmation of a metastatic focus of a previously diagnosed tumor. CONCLUSIONS: The anchored, multiplex PCR-based gene fusion assay is a powerful orthogonal tool in helping diagnose mesenchymal neoplasms on cytology specimens. The material obtained for cytologic analysis yields sufficient quality/quantity of tissue in the majority of cases tested.

Blood-based screening for HPV-associated cancers.

Background: HPV-associated oropharyngeal cancer (HPV+OPSCC) is the most common HPV-associated cancer in the United States yet unlike cervical cancer lacks a screening test. HPV+OPSCCs are presumed to start developing 10-15 years prior to clinical diagnosis. Circulating tumor HPV DNA (ctHPVDNA) is a sensitive and specific biomarker for HPV+OPSCC. Taken together, blood-based screening for HPV+OPSCC may be feasible years prior to diagnosis. Methods: We developed an HPV whole genome sequencing assay, HPV-DeepSeek, with 99% sensitivity and specificity at clinical diagnosis. 28 plasma samples from HPV+OPSCC patients collected 1.3-10.8 years prior to diagnosis along with 1:1 age and gender-matched controls were run on HPV-DeepSeek and an HPV serology assay. Results: 22/28 (79%) of cases and 0/28 controls screened positive for HPV+OPSCC with 100% detection within four years of diagnosis and a maximum lead time of 7.8 years. We next applied a machine learning model classifying 27/28 cases (96%) with 100% detection within 10 years. Plasma-based PIK3CA gene mutations, viral genome integration events and HPV serology were used to orthogonally validate cancer detection with 68% (19/28) of the cohort having multiple cancer signals detected. Molecular fingerprinting of HPV genomes was performed across patients demonstrating that each viral genome was unique, ruling out contamination. In patients with tumor blocks from diagnosis (15/28), molecular fingerprinting was performed within patients confirming the same viral genome across time. Conclusions: We demonstrate accurate blood-based detection of HPV-associated cancers with lead times up to 10 years before clinical cancer diagnosis and in doing so, highlight the enormous potential of ctDNA-based cancer screening.

Outlier Expression of Isoforms by Targeted or Total RNA Sequencing Identifies Clinically Significant Genomic Variants in Hematolymphoid Tumors.

Recognition of aberrant gene isoforms due to DNA events can impact risk stratification and molecular classification of hematolymphoid tumors. In myelodysplastic syndromes, KMT2A partial tandem duplication (PTD) was one of the top adverse predictors in the International Prognostic Scoring System-Molecular study. In B-cell acute lymphoblastic leukemia (B-ALL), ERG isoforms have been proposed as markers of favorable-risk DUX4 rearrangements, whereas deletion-mediated IKZF1 isoforms are associated with adverse prognosis and have been extended to the high-risk IKZF1plus signature defined by codeletions, including PAX5. In this limited study, outlier expression of isoforms as markers of IKZF1 intragenic or 3' deletions, DUX4 rearrangements, or PAX5 intragenic deletions were 92.3% (48/52), 90% (9/10), or 100% (9/9) sensitive, respectively, and 98.7% (368/373), 100% (35/35), or 97.1% (102/105) specific, respectively, by targeted RNA sequencing, and 84.0% (21/25), 85.7% (6/7), or 81.8% (9/11) sensitive, respectively, and 98.2% (109/111), 98.4% (127/129), or 98.7% (78/79) specific, respectively, by total RNA sequencing. Comprehensive split-read analysis identified expressed DNA breakpoints, cryptic splice sites associated with IKZF1 3' deletions, PTD of IKZF1 exon 5 spanning N159Y in B-ALL with mutated IKZF1 N159Y, and truncated KMT2A-PTD isoforms. Outlier isoforms were also effective targeted RNA markers for PAX5 intragenic amplifications (B-ALL), KMT2A-PTD (myeloid malignant cancers), and rare NOTCH1 intragenic deletions (T-cell acute lymphoblastic leukemia). These findings support the use of outlier isoform analysis as a robust strategy for detecting clinically significant DNA events.

Prognostic biomarkers for survival in mucosal melanoma.

Mucosal melanoma (MM) is a rare subtype of melanoma with an aggressive clinical course. In cutaneous melanoma (CM), the absence of pigmentation and presence of NRAS/KRAS mutations are biomarkers indicating an aggressive clinical course with shorter overall survival. Similar data for MM are missing. We present the real-world outcome data in a cohort of genotyped MM patients and assessed the prognostic relevance of pigmentation- and NRAS/KRAS mutation status. We correlated pathological reports and clinical data with overall survival of patients with MM. Furthermore, we performed clinically integrated molecular genotyping and analyzed real world treatment regimens for covariates associated with clinical outcome. We identified 39 patients with available clinical and molecular data. Patients with amelanotic MM had a significantly shorter overall survival (p = .003). In addition, the presence of a NRAS or KRAS mutation was significantly associated with poor overall survival (NRAS or KRAS p = .024). Currently, it is unknown if the same prognostic relevance for the lack of pigmentation and RAS mutations in CM, exists in MM. Here we analyzed a cohort of MM for outcome measures and determined that two known prognostic biomarkers for CM are in fact novel prognosticators for MM.

Effectors Enabling Adaptation to Mitochondrial Complex I Loss in Hürthle Cell Carcinoma.

Oncocytic (Hürthle cell) carcinoma of the thyroid (HCC) is genetically characterized by complex I mitochondrial DNA mutations and widespread chromosomal losses. Here, we utilize RNA sequencing and metabolomics to identify candidate molecular effectors activated by these genetic drivers. We find glutathione biosynthesis, amino acid metabolism, mitochondrial unfolded protein response, and lipid peroxide scavenging to be increased in HCC. A CRISPR-Cas9 knockout screen in a new HCC model reveals which pathways are key for fitness, and highlights loss of GPX4, a defense against lipid peroxides and ferroptosis, as a strong liability. Rescuing complex I redox activity with the yeast NADH dehydrogenase (NDI1) in HCC cells diminishes ferroptosis sensitivity, while inhibiting complex I in normal thyroid cells augments ferroptosis induction. Our work demonstrates unmitigated lipid peroxide stress to be an HCC vulnerability that is mechanistically coupled to the genetic loss of mitochondrial complex I activity. SIGNIFICANCE: HCC harbors abundant mitochondria, mitochondrial DNA mutations, and chromosomal losses. Using a CRISPR-Cas9 screen inspired by transcriptomic and metabolomic profiling, we identify molecular effectors essential for cell fitness. We uncover lipid peroxide stress as a vulnerability coupled to mitochondrial complex I loss in HCC. See related article by Frank et al., p. 1884. This article is highlighted in the In This Issue feature, p. 1749.

A Comprehensive Study on the Diagnosis and Management of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features.

Background: Since the noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs) was introduced in 2016, most retrospective studies have included cases diagnosed as encapsulated follicular variant of papillary thyroid carcinoma. We investigate a cohort diagnosed with NIFTP at resection. Methods: Retrospective institutional cohort of NIFTP from 2016 to 2022, including clinical, cytological, and molecular data for 319 cases (6.6% of thyroid surgeries, 183 cases as NIFTP-only). Results: The patient cohort had unifocal or multifocal thyroid nodules. Female:male ratio was 2.7:1, mean age was 52 years and median NIFTP size was 2.1 cm. NIFTP was associated with multiple nodules in 23% patients (n = 73) and 12% of NIFTP were multifocal (n = 39). Fine needle aspiration (FNA) of NIFTP (n = 255) were designated as nondiagnostic = 5%, benign = 13%, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) = 49%, follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) = 17%, suspicious for malignancy = 12%, or malignant = 4%. Molecular alterations were identified in 93% (n = 114), RAS or RAS-like. Thyroid Imaging Reporting and Data System (TI-RADS) score 4 was recorded in 50% of NIFTP, followed by scores 3 and 5 (26% and 20%, respectively). We also investigated the factors associated with extent of surgery. In our NIFTP-only group (n = 183), 66% were identified after hemithyroidectomy (HT) and 34% after total thyroidectomy (TT). On univariate analysis, TT patients demonstrated higher Bethesda category by FNA, more often had aberrant preoperative thyroid function, and/or underwent an FNA of additional nodule(s). With multivariable regression, Bethesda V NIFTP, in the presence of other nodules being evaluated by FNA and aberrant preoperative thyroid function, independently predicts TT. Bethesda II NIFTP correlated significantly with HT. Fifty-two patients (28%) with NIFTP-only had at least one postoperative surveillance ultrasound. In the NIFTP-only cohort, no HT patients had completion thyroidectomy or received postoperative radioactive iodine. No recurrence or metastases were recorded with median follow-up of 35 months (6-76 months; n = 120). Conclusions: Given this large cohort of NIFTP, including a large subset of isolated NIFTP-only, some with >6 years of follow-up and no tumor recurrences, consensus practical guidelines are needed for adequate postoperative management. Given the American Thyroid Association (ATA) provides guidelines for management of low-risk malignancies, guidance regarding that for borderline/biologically uncertain tumors, including NIFTP, is a reasonable next step.

Molecular Evidence for Olfactory Neuroblastoma as a Tumor of Malignant Globose Basal Cells.

Olfactory neuroblastoma (ONB, esthesioneuroblastoma) is a sinonasal cancer with an underdeveloped diagnostic toolkit, and is the subject of many incidents of tumor misclassification throughout the literature. Despite its name, connections between the cancer and normal cells of the olfactory epithelium have not been systematically explored and markers of olfactory epithelial cell types are not deployed in clinical practice. Here, we utilize an integrated human-mouse single-cell atlas of the nasal mucosa, including the olfactory epithelium, to identify transcriptomic programs that link ONB to a specific population of stem/progenitor cells known as olfactory epithelial globose basal cells (GBCs). Expression of a GBC transcription factor NEUROD1 distinguishes both low- and high-grade ONB from sinonasal undifferentiated carcinoma, a potential histologic mimic with a distinctly unfavorable prognosis. Furthermore, we identify a reproducible subpopulation of highly proliferative ONB cells expressing the GBC stemness marker EZH2, suggesting that EZH2 inhibition may play a role in the targeted treatment of ONB. Finally, we study the cellular states comprising ONB parenchyma using single-cell transcriptomics and identify evidence of a conserved GBC transcriptional regulatory circuit that governs divergent neuronal-versus-sustentacular differentiation. These results link ONB to a specific cell type for the first time and identify conserved developmental pathways within ONB that inform diagnostic, prognostic, and mechanistic investigation.

Special Considerations in the Molecular Diagnostics of Pediatric Neoplasms.

Pediatric neoplasms have unique demands, including triaging of small biopsies for multiple testing modalities, and a pediatric cancer genome that is notably different from the adult cancer genome. Pediatric cancers are more likely to be driven by gene fusions and typically have a lower tumor mutational burden. Clinically relevant unique molecular targets exist within pediatric cancers, with important implications for diagnosis, prognosis, and treatment selection. Hence, assays and interpretation workflows must be designed thoughtfully to support molecular tumor profiling for children with cancer, including accommodation of small samples, detection of gene fusions, and consideration of potential germline associations.

Undifferentiated Embryonal Sarcoma of the Liver With Rhabdoid Morphology Mimicking Carcinoma: Expanding the Morphologic Spectrum or a Distinct Variant?

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare aggressive neoplasm that occurs predominantly in children. Like mesenchymal hamartoma of the liver (MHL), UESL harbors recurrent rearrangements involving 19q13.3 and 19q13.4, a region of the genome that contains a primate-specific cluster of micro-RNAs. Here, we present a case of a high-grade neoplasm that arose in the left hepatic lobe of a 5-year-old male and gave rise to widespread lymph node, visceral, and soft tissue metastases. The tumor was composed of sheets, tubules, and papillae of epithelioid cells with rhabdoid morphology. INI1 and BRG1 expression were retained. Tumor cells diffusely expressed epithelial markers, including multiple keratins. While the morphologic and immunophenotypic features were suggestive of poorly differentiated carcinoma with rhabdoid features, the tumor was found to harbor the t(11;19)(q13;q13.3) translocation characteristic of UESL, as well as a TP53 mutation. Given the clinical presentation, imaging, clinical course, the tumor was classified as UESL with unusual, carcinoma-like histopathologic features. In the context of an unclassified high-grade hepatic tumor in a young child, molecular or cytogenetic testing for chromosome 19q13 alterations should be considered.

Intraductal carcinoma of the salivary gland with NCOA4-RET: expanding the morphologic spectrum and an algorithmic diagnostic approach.

After the publication of the 2017 World Health Organization Classification of Head and Neck Tumours, there has been increasing interest in the classification of newly categorized intraductal carcinomas. Intraductal carcinoma (IC) is an indolent tumor, typically arising in the parotid gland, with an intact myoepithelial layer and a cystic, papillary, often cribriform architecture. Early studies of IC identified a heterogeneous group of molecular alterations driving neoplasia, and recent studies have defined three primary morphological/immunohistochemical variants, subsequently linking these morphologic variants with defined molecular signatures. Although studies to date have pointed toward distinct molecular alterations after histological classification, this study used a novel approach, focusing primarily on six cases of IC with NCOA4-RET gene rearrangement as determined by next-generation sequencing and describing the spectrum of clinicopathologic findings within that molecularly-defined group, among them a unique association between the NCOA4-RET fusion and hybrid variant IC and the first case of IC arising in association with a pleomorphic adenoma. RET-rearranged IC show histological and immunohistochemical overlap with the more widely recognized secretory carcinoma, including low-grade morphology, a lumen-forming or microcystic growth pattern, and co-expression of S100, SOX10, and mammaglobin, findings undoubtedly leading to misdiagnosis. Typically regarded to have ETV6-NTRK3 fusions, secretory carcinomas may alternatively arise with RET fusions as well. Adding our cohort of six NCOA4-RET fusion-positive IC compared with four cases of secretory carcinoma with ETV6-RET fusions and a single case of fusion-negative IC with salivary duct carcinoma-like genetics, we propose a diagnostic algorithm that integrates histological elements, including atypia and invasiveness, and the likelihood of specific molecular alterations to increase diagnostic accuracy in what can be a very subtle diagnosis with important clinical implications.

Identification of EWSR1-NFATC2 fusion in simple bone cysts.

AIMS: Simple bone cysts are benign intramedullary tumours primarily involving the long bones in skeletally immature individuals. Several mechanisms have been proposed for their pathogenesis. Although the diagnosis is typically straightforward, the interpretation can be problematic, because of superimposed fracture causing them to resemble aneurysmal bone cysts and other tumours. EWSR1-NFATC2 or FUS-NFATC2 fusions, which are characteristic of a subset of aggressive round cell sarcomas, have been recently detected in simple bone cysts. The aim of this study was to examine the clinicopathological and molecular features in a series of simple bone cysts. METHODS AND RESULTS: Using RNA-based next-generation sequencing and/or fluorescence in-situ hybridisation, we investigated the presence of EWSR1 or FUS rearrangements in nine simple bone cysts. The patients were five females and four males, aged 3-23 years (median, 14 years); the tumours ranged from 19 mm to 160 mm (median, 46 mm) in size, and involved the femur (n = 3), humerus (n = 2), fibula (n = 2), tibia (n = 1), and iliac wing (n =1). We identified three cases with EWSR1-NFATC2 fusion (showing identical breakpoints to those in EWSR1-NFATC2 sarcomas) and one additional case with FUS rearrangement. Unlike in EWSR1-NFATC2 sarcomas, immunohistochemical expression of NKX3.1 and NKX2.2 was absent in two simple bone cysts tested. CONCLUSIONS: More than 40% of simple bone cysts harbour genetic alterations confirming that they are neoplastic, investigation of EWSR1 and/or FUS rearrangement may help to distinguish simple bone cysts from mimics, and NFATC2 rearrangement is not pathognomonic of malignancy.

Clinical sensitivity and interpretation of PCR and serological COVID-19 diagnostics for patients presenting to the hospital.

The diagnosis of COVID-19 requires integration of clinical and laboratory data. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic assays play a central role in diagnosis and have fixed technical performance metrics. Interpretation becomes challenging because the clinical sensitivity changes as the virus clears and the immune response emerges. Our goal was to examine the clinical sensitivity of two most common SARS-CoV-2 diagnostic test modalities, polymerase chain reaction (PCR) and serology, over the disease course to provide insight into their clinical interpretation in patients presenting to the hospital. We conducted a single-center, retrospective study. To derive clinical sensitivity of PCR, we identified 209 PCR-positive SARS-CoV-2 patients with multiple PCR test results (624 total PCR tests) and calculated daily sensitivity from date of symptom onset or first positive test. Clinical sensitivity of PCR decreased with days post symptom onset with >90% clinical sensitivity during the first 5 days after symptom onset, 70%-71% from Days 9 to 11, and 30% at Day 21. To calculate daily clinical sensitivity by serology, we utilized 157 PCR-positive patients with a total of 197 specimens tested by enzyme-linked immunosorbent assay for IgM, IgG, and IgA anti-SARS-CoV-2 antibodies. In contrast to PCR, serological sensitivity increased with days post symptom onset with >50% of patients seropositive by at least one antibody isotype after Day 7, >80% after Day 12, and 100% by Day 21. Taken together, PCR and serology are complimentary modalities that require time-dependent interpretation. Superimposition of sensitivities over time indicate that serology can function as a reliable diagnostic aid indicating recent or prior infection.

Pan-sarcoma genomic analysis of KMT2A rearrangements reveals distinct subtypes defined by YAP1-KMT2A-YAP1 and VIM-KMT2A fusions.

Sarcomas are driven by diverse pathogenic mechanisms, including gene rearrangements in a subset of cases. Rare soft tissue sarcomas containing KMT2A fusions have recently been reported, characterized by a predilection for young adults, sclerosing epithelioid fibrosarcoma-like morphology, and an often aggressive course. Nonetheless, clinicopathologic and molecular descriptions of KMT2A-rearranged sarcomas remain limited. In this study, we identified by targeted next-generation RNA sequencing an index patient with KMT2A fusion-positive soft tissue sarcoma. In addition, we systematically searched for KMT2A structural variants in a comprehensive genomic profiling database of 14,680 sarcomas interrogated by targeted next-generation DNA and/or RNA sequencing. We characterized the clinicopathologic and molecular features of KMT2A fusion-positive sarcomas, including KMT2A breakpoints, rearrangement partners, and concurrent genetic alterations. Collectively, we identified a cohort of 34 sarcomas with KMT2A fusions (0.2%), and YAP1 was the predominant partner (n = 16 [47%]). Notably, a complex rearrangement with YAP1 consistent with YAP1-KMT2A-YAP1 fusion was detected in most cases, with preservation of KMT2A CxxC-binding domain in the YAP1-KMT2A-YAP1 fusion and concurrent deletions of corresponding exons in KMT2A. The tumors often affected younger adults (age 20-66 [median 40] years) and histologically showed variably monomorphic epithelioid-to-spindle shaped cells embedded in a dense collagenous stroma. Ultrastructural evidence of fibroblastic differentiation was noted in one tumor examined. Our cohort also included two sarcomas with VIM-KMT2A fusions, each harboring concurrent mutations in CTNNB1, SMARCB1, and ARID1A and characterized histologically by sheets of spindle-to-round blue cells. The remaining 16 KMT2A-rearranged sarcomas in our cohort exhibited diverse histologic subtypes, each with unique novel fusion partners. In summary, KMT2A-fusion-positive sarcomas most commonly exhibit sclerosing epithelioid fibrosarcoma-like morphology and complex YAP1-KMT2A-YAP1 fusions. Cases also include rare spindle-to-round cell sarcomas with VIM-KMT2A fusions and tumors of diverse histologic subtypes with unique KMT2A fusions to non-YAP1 non-VIM partners.

Genetic Variation in the Platelet Endothelial Aggregation Receptor 1 Gene Results in Endothelial Dysfunction.

Platelet Endothelial Aggregation Receptor 1 (PEAR1) is a newly identified membrane protein reported to be involved in multiple vascular and thrombotic processes. While most studies to date have focused on the effects of this receptor in platelets, PEAR1 is located in multiple tissues including the endothelium, where it is most highly expressed. Our first objective was to evaluate the role of PEAR1 in endothelial function by examining flow-mediated dilation of the brachial artery in 641 participants from the Heredity and Phenotype Intervention Heart Study. Our second objective was to further define the impact of PEAR1 on cardiovascular disease computationally through meta-analysis of 75,000 microarrays, yielding insights regarding PEAR1 function, and predictions of phenotypes and diseases affected by PEAR1 dysregulation. Based on the results of this meta-analysis we examined whether genetic variation in PEAR1 influences endothelial function using an ex vivo assay of endothelial cell migration. We observed a significant association between rs12041331 and flow-mediated dilation in participants of the Heredity and Phenotype Intervention Heart Study (P = 0.02). Meta-analysis results revealed that PEAR1 expression is highly correlated with several genes (e.g. ANG2, ACVRL1, ENG) and phenotypes (e.g. endothelial cell migration, angiogenesis) that are integral to endothelial function. Functional validation of these results revealed that PEAR1 rs12041331 is significantly associated with endothelial migration (P = 0.04). Our results suggest for the first time that genetic variation of PEAR1 is a significant determinant of endothelial function through pathways implicated in cardiovascular disease.