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The differential diagnosis of malignant spindle cell neoplasms in the breast most frequently rests between malignant phyllodes tumor (MPT) and metaplastic carcinoma (MBC). Diagnosis of MPT can be challenging due to diffuse stromal overgrowth, keratin (CK) and/or p63 immunopositivity, and absent CD34 expression, which can mimic MBC, especially in core biopsies. Distinction of MPT from MBC has clinical implications, with differences in surgical approach, chemotherapy, and radiation. In this study, we evaluated MPT (78 tumors, 64 patients) for stromal CK, p63, and CD34 expression and profiled a subset (n=31) by targeted next-generation DNA sequencing (NGS), with comparison to MBC (n=44). Most MPT (71%) were CK+ and/or p63+, including 32% CK+ (25/77 focal) and 65% p63+ (32/66 focal, 10/66 patchy, 1/66 diffuse). Thirty-percent of MPT expressed both CK and p63 (20/66), compared to 95% of MBC (40/42, p<0.001). CK and/or p63 were positive in CD34+ and CD34- MPT. Recurrent genetic aberrations in MPT involved TERT, TP53, MED12, CDKN2A, chromatin modifiers, growth factor receptors/ligands, and PI-3K and MAPK pathway genes. Only MED12 (39%, 12/31) and SETD2 (13%, 4/31) were exclusively mutated in MPT and not MBC (p<0.001 and p=0.044, respectively), whereas PIK3R1 mutations were only found in MBC (35%, 13/35, p<0.001). Comparative literature review additionally identified ARID1B, EGFR, FLNA, NRAS, PDGFRB, RAD50, and RARA alterations enriched or exclusively in MPT versus MBC. MED12 was mutated in MPT with diffuse stromal overgrowth (53%, 9/17), CD34- MPT (41%, 7/17), and CK+ and/or p63+ MPT (39%, 9/23), including 36% of CD34- MPT with CK and/or p63 expression. Overall, MED12 mutation and/or CD34 expression were observed in 68% (21/31) MPT, including 61% (14/23) of CK+ and/or p63+ tumors. Our results emphasize the prevalence of CK and p63 expression in MPT and demonstrate diagnostic utility of NGS, especially in MPT with confounding factors that can mimic MBC.
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In this case report, dual-energy CT was critical in the diagnosis of acute mesenteric ischemia by differentiating normal contrast-enhanced bowel and hemorrhagic necrosis. Iodine map showed a segment of small bowel with minimal contrast enhancement, and virtual non-contrast imaging revealed hyperattenuating bowel. This finding changed management for the patient and prevented complications from impending bowel perforation. Histopathological analysis confirmed hemorrhagic necrosis of the bowel segment. In cases of suspected bowel ischemia, dual-energy CT can distinguish bowel wall hemorrhage from contrast enhancement and allow for accurate diagnosis.
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Yodo , Isquemia Mesentérica , Medios de Contraste , Hemorragia Gastrointestinal , Humanos , Intestino Delgado , Isquemia , Isquemia Mesentérica/diagnóstico por imagen , Necrosis/complicaciones , Necrosis/patología , Tomografía Computarizada por Rayos X/métodosRESUMEN
BACKGROUND: BRCA1-associated protein (BAP1) is a tumor suppressor whose loss is associated with various malignancies. The primary cilium is an organelle involved in signal transduction and cell cycle progression. Primary cilia have been shown to be absent in melanoma but retained to some extent in melanocytic nevi, and the severity of dysplasia influences the degree of cilia loss. Additionally, studies have revealed roles for BAP1 in centrosome and mitotic spindle formation. Because the primary cilium is nucleated on the mother centriole, we examined the connection between the presence of primary cilia and the formation of centrosomes in BAP1-inactivated melanocytic tumors (BIMTs). METHODS: We evaluated the cilia and centrosomes in 11 BIMTs and five conventional melanocytic nevi using immunofluorescence staining of acetylated alpha-tubulin and gamma-tubulin. RESULTS: We found that, compared to nevi, BIMTs show loss of primary cilia and amplification of centrosomes. Occasional nevi also showed increased centrioles; however, these foci of amplification were more likely to be ciliated than those in BIMTs. CONCLUSIONS: Although centrosome amplification does not absolutely correlate with loss of primary cilia in melanocytic neoplasms, absence of BAP1 exacerbates the phenotype. Moreover, aberrant centrosome and cilia formation are likely critical in the pathogenesis of other BAP1-inactivated tumors.
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Centrosoma/patología , Cilios/patología , Melanoma/patología , Neoplasias Cutáneas/patología , Proteínas Supresoras de Tumor/genética , Ubiquitina Tiolesterasa/genética , Adolescente , Adulto , Anciano , Femenino , Silenciador del Gen , Humanos , Masculino , Melanoma/genética , Persona de Mediana Edad , Nevo Pigmentado/genética , Nevo Pigmentado/patología , Neoplasias Cutáneas/genética , Adulto JovenRESUMEN
While years of investigation have elucidated many aspects of embryonic stem cell (ESC) regulation, the contributions of post-transcriptional and translational mechanisms to the pluripotency network remain largely unexplored. In particular, little is known in ESCs about the function of RNA binding proteins (RBPs), the protein agents of post-transcriptional regulation. We performed an unbiased RNAi screen of RBPs in an ESC differentiation assay and identified two related genes, NF45 (Ilf2) and NF90/NF110 (Ilf3), whose knockdown promoted differentiation to an epiblast-like state. Characterization of NF45 KO, NF90 + NF110 KO, and NF110 KO ESCs showed that loss of NF45 or NF90 + NF110 impaired ESC proliferation and led to dysregulated differentiation down embryonic lineages. Additionally, we found that NF45 and NF90/NF110 physically interact and influence the expression of each other at different levels of regulation. Globally across the transcriptome, NF45 KO ESCs and NF90 + NF110 KO ESCs show similar expression changes. Moreover, NF90 + NF110 RNA immunoprecipitation (RIP)-seq in ESCs suggested that NF90/NF110 directly regulate proliferation, differentiation, and RNA-processing genes. Our data support a model in which NF45, NF90, and NF110 operate in feedback loops that enable them, through both overlapping and independent targets, to help balance the push and pull of pluripotency and differentiation cues.
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Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Proteína del Factor Nuclear 45/metabolismo , Proteínas del Factor Nuclear 90/metabolismo , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Ratones , Proteína del Factor Nuclear 45/antagonistas & inhibidores , Proteína del Factor Nuclear 45/genética , Proteínas del Factor Nuclear 90/antagonistas & inhibidores , Proteínas del Factor Nuclear 90/genética , Unión Proteica , Interferencia de ARNRESUMEN
Introduction: Fluorescence in situ hybridization (FISH) is an essential ancillary study used to identify clinically aggressive subsets of large B-cell lymphomas that have MYC, BCL2, or BCL6 rearrangements. Small-volume biopsies such as fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB) are increasingly used to diagnose lymphoma and obtain material for ancillary studies such as FISH. However, the performance of FISH in small biopsies has not been thoroughly evaluated or compared to surgical biopsies. Methods: We describe the results of MYC, BCL2, and BCL6 FISH in a series of 222 biopsy specimens, including FNAB with cell blocks, CNBs, and surgical excisional or incisional biopsies from 208 unique patients aggregated from 6 academic medical centers. A subset of patients had FNAB followed by a surgical biopsy (either CNB or excisional biopsy) obtained from the same or contiguous anatomic site as part of the same clinical workup; FISH results were compared for these paired specimens. Results: FISH had a low hybridization failure rate of around 1% across all specimen types. FISH identified concurrent MYC and BCL2 rearrangements in 20 of 197 (10%) specimens and concurrent MYC and BCL6 rearrangements in 3 of 182 (1.6%) specimens. The paired FNAB and surgical biopsy specimens did not show any discrepancies for MYC or BCL2 FISH; of the 17 patients with 34 paired cytology and surgical specimens, only 2 of the 49 FISH probes compared (4% of all comparisons) showed any discrepancy and both were at the BCL6 locus. One discrepancy was due to necrosis of the CNB specimen causing a false negative BCL6 FISH result when compared to the FNAB cell block that demonstrated a BCL6 rearrangement. Discussion: FISH showed a similar hybridization failure rate in all biopsy types. Ultimately, MYC, BCL2, or BCL6 FISH showed 96% concordance when compared across paired cytology and surgical specimens, suggesting FNAB with cell block is equivalent to other biopsy alternatives for evaluation of DLBCL or HGBCL FISH testing.
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While mature cystic teratomas are relatively common ovarian neoplasms typically comprising of multiple embryologic cell types, a specific monodermal subtype involving thyroid tissue, struma ovarii, can rarely be seen. This case reviews typical imaging characteristics with MRI and ultrasound of struma ovarii and details possible complications from these masses with intraoperative and histologic correlation.
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Quiste Dermoide , Neoplasias Ováricas , Estruma Ovárico , Teratoma , Humanos , Neoplasias Ováricas/complicaciones , Neoplasias Ováricas/diagnóstico por imagen , Neoplasias Ováricas/cirugía , Estruma Ovárico/patología , Estruma Ovárico/cirugía , Teratoma/complicaciones , Teratoma/diagnóstico por imagen , Teratoma/cirugíaRESUMEN
Mutations in the transcriptional regulator Mecp2 cause the severe X-linked neurodevelopmental disorder Rett syndrome (RTT). In this study, we investigate genes that function downstream of MeCP2 in cerebral cortex circuitry, and identify upregulation of Irak1, a central component of the NF-κB pathway. We show that overexpression of Irak1 mimics the reduced dendritic complexity of Mecp2-null cortical callosal projection neurons (CPN), and that NF-κB signalling is upregulated in the cortex with Mecp2 loss-of-function. Strikingly, we find that genetically reducing NF-κB signalling in Mecp2-null mice not only ameliorates CPN dendritic complexity but also substantially extends their normally shortened lifespan, indicating broader roles for NF-κB signalling in RTT pathogenesis. These results provide new insight into both the fundamental neurobiology of RTT, and potential therapeutic strategies via NF-κB pathway modulation.
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Regulación de la Expresión Génica/fisiología , Proteína 2 de Unión a Metil-CpG/metabolismo , FN-kappa B/metabolismo , Síndrome de Rett/metabolismo , Transducción de Señal/fisiología , Animales , Femenino , Quinasas Asociadas a Receptores de Interleucina-1/genética , Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Masculino , Proteína 2 de Unión a Metil-CpG/genética , Ratones , Ratones Noqueados , FN-kappa B/genética , Síndrome de Rett/genéticaRESUMEN
Establishment, maintenance, and exit from pluripotency require precise coordination of a cell's molecular machinery. Substantial headway has been made in deciphering many aspects of this elaborate system, particularly with respect to epigenetics, transcription, and noncoding RNAs. Less attention has been paid to posttranscriptional regulatory processes such as alternative splicing, RNA processing and modification, nuclear export, regulation of transcript stability, and translation. Here, we introduce the RNA binding proteins that enable the posttranscriptional regulation of gene expression, summarizing current and ongoing research on their roles at different regulatory points and discussing how they help script the fate of pluripotent stem cells.
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Células Madre Pluripotentes/metabolismo , Proteínas de Unión al ARN/metabolismo , Empalme Alternativo , Animales , Humanos , Poliadenilación , Biosíntesis de Proteínas , Estabilidad del ARNRESUMEN
Ectopic expression of specific factors such as Oct4, Sox2, and Klf4 (OSK) is sufficient to reprogram somatic cells into induced pluripotent stem cells (iPSCs). In this study, we examine the paths taken by cells during the reprogramming process by following the transcriptional activation of two pluripotent miRNA clusters (mir-290 and mir-302) in individual cells in vivo and in vitro with knockin reporters. During embryonic development and embryonic stem cell differentiation, all cells sequentially expressed mir-290 and mir-302. In contrast, during OSK-induced reprogramming, cells activated the miRNA loci in a stochastic, nonordered manner. However, the addition of Sall4 to the OSK cocktail led to a consistent reverse sequence of locus activation (mir-302 then mir-290) and increased reprogramming efficiency. These results demonstrate that cells can follow multiple paths during the late stages of reprogramming, and that the trajectory of any individual cell is strongly influenced by the combination of factors introduced.
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Reprogramación Celular/fisiología , MicroARNs/metabolismo , Animales , Reprogramación Celular/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Femenino , Factor 4 Similar a Kruppel , Masculino , Ratones , MicroARNs/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Tuberous sclerosis complex is a disease caused by mutations in two tumor-suppressor genes, TSC1 and TSC2. The TSC1 protein, also known as hamartin, has a critical role in controlling mTOR signalling. TSC1 does not bear apparent sequence homology with other proteins. Here we show that the N-terminal half of yeast TSC1 forms a protease-resistant domain, which is evolutionarily conserved. The crystal structure of this yeast TSC1 core domain shows that it contains a pseudo-HEAT repeat fold with its C-terminal end capped by a helical subdomain. This allows us to model the three-dimensional structure of the human TSC1 N-terminal domain (TSC1-NTD), which anchors essentially all pathogenic TSC1 missense mutations found in tuberous sclerosis patients. Interestingly, most pathogenic mutations map inside of the folded TSC1-NTD structure, whereas most non-pathogenic variants are on the structural surface. This indicates that the disruption of the TSC1-NTD globular structure is a major cause of tuberous sclerosis.