Rapid information processing in the central nervous system requires the myelination of axons by oligodendrocytes. The transcription factor Sox2 and its close relative Sox3 redundantly regulate the development of myelin-forming oligodendrocytes, but little is known about the underlying molecular mechanisms. Here, we characterized the expression profile of cultured oligodendroglial cells during early differentiation and identified Bcas1, Enpp6, Zfp488 and Nkx2.2 as major downregulated genes upon Sox2 and Sox3 deletion. An analysis of mice with oligodendrocyte-specific deletion of Sox2 and Sox3 validated all four genes as downstream targets in vivo. Additional functional assays identified regulatory regions in the vicinity of each gene that are responsive to and bind both Sox proteins. Bcas1, Enpp6, Zfp488 and Nkx2.2 therefore likely represent direct target genes and major effectors of Sox2 and Sox3. Considering the preferential expression and role of these genes in premyelinating oligodendrocytes, our findings suggest that Sox2 and Sox3 impact oligodendroglial development at the premyelinating stage with Bcas1, Enpp6, Zfp488 and Nkx2.2 as their major effectors.

Background Round cell sarcomas pose diagnostic challenges due to overlapping histopathological features, necessitating precise immunohistochemical markers for accurate categorization. NKX2.2 has emerged as a sensitive diagnostic tool, particularly in Ewing sarcoma. This study extends this understanding to various round-cell sarcomas, shedding light on the potential diagnostic utility of NKX2.2 beyond its established role. The nuanced exploration of NKX2.2 expression aims to enhance diagnostic strategies, prognostic assessments, and therapeutic developments in the landscape of sarcoma research. Methodology Cases were retrieved from the surgical pathology and consultation files of Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan. Representative hematoxylin and eosin-stained slides of six different types of already confirmed tumors, including lymphoblastic lymphoma, neuroblastoma, rhabdomyosarcoma, synovial sarcoma, Wilms tumor, and Ewing sarcoma, were reviewed by a panel of pathologists. Immunohistochemistry, utilizing a rabbit anti-NKX2.2 monoclonal antibody, was performed on formalin-fixed paraffin-embedded tissue sections. The presence of NKX2.2 was defined as moderate or high nuclear immunoreactivity in at least 5% of cells. Results The histopathological examination revealed characteristic features in each sarcoma subtype, aligning with established diagnostic criteria. In Lymphoblastic lymphoma, T-cell lineage was confirmed through TdT expression, while the atypical finding of focal NKX 2.2 expression hinted at genetic diversity. Neuroblastoma exhibited the expected salt and pepper chromatin pattern, with NKX 2.2 expression raising questions about its prognostic significance. Rhabdomyosarcoma presented primitive cells expressing desmin, and NKX 2.2 focal expression echoed previous subtype-associated studies. Synovial sarcoma displayed both monophasic and biphasic growth patterns and TLE1 expression, with NKX 2.2 variation suggesting tumor heterogeneity. In Wilms tumor, the characteristic WT1 expression was observed, while NKX2.2\'s absence reaffirmed its irrelevance in this context. Ewing sarcoma displayed the anticipated homogenous cell population, strong NKX2.2 expression, and CD99 positivity across various sites. Furthermore, age and gender impact on this range of sarcomas found no significant relation with an expression of NKX2.2. Conclusion In conclusion, the diverse expression profiles of diagnostic markers discovered in this study, particularly the atypical expression of NKX2.2 beyond its established role in Ewing sarcoma, signify a significant advancement. This unique finding accentuates the potential diagnostic importance of NKX2.2 in various sarcomas, presenting a novel dimension to our understanding of these malignancies.

Meningioma is a common brain tumour which has neither a specific detection nor treatment method. The Sonic hedgehog (Shh) cell signaling pathway is a crucial regulatory pathway of mammalian organogenesis and tumorigenesis including meningioma. Shh cell signalling pathway cascade function by main transcription factor Gli1 and which further regulates in its downstream to Pax6 and Nkx2.2. This current study is aimed to explore the regulation of the Sonic hedgehog-Gli1 cell signaling pathway and its potential downstream targets in meningioma samples. A total of 24 surgically resected meningioma samples were used in this current study.Cytological changes were assessed using electron microscopic techniques as well as hematoxylin & eosin and DAPI staining. The expression pattern of Gli1, Nkx2.2 and Pax6 transcription factors were determined by using immunohistochemistry. The mRNA expression was assessed using RT-qPCR assays. Later, the whole transcriptome analysis of samples was performed with the amploseq technique. Results were compared with those obtained in normal human brain tissue (or normal meninges). Compared to the normal human brain tissue, meningioma samples showed crowded nuclei with morphological changes. Transcription factor Nkx2.2 expressed highly in all samples (24/24, 100%). Twenty-one of the 24 meningiomas (88%) showed high Gli1 and Pax6 expression. Whole transcriptome analysis of two meningioma samples also exhibited a very high increase in Gli1 expression signal in meningioma samples as compare to normal control. Hence, we may conclude that the Shh-Gli1 pathway is aberrantly activated in meningioma cells and is canonically upregulating the expression of transcription factors Pax6 and Nkx2.2.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s12291-022-01085-1.

Ewing\'s sarcoma (ES) is a malignant small round cell neuroectodermal tumour primarily affecting children in the first and second decade of life. Since ES is difficult to control, early diagnosis is crucial, and the treatment requires a multimodality approach constituting chemotherapy, surgery and radiotherapy. Here, we present a case of ES of orbit in a 17-year-old female diagnosed in 2021. This case report focuses on the clinicopathological presentation and management principles of this rare manifestation of the disease that unilaterally infiltrated into the extraconal space of the orbit as well as the I/L frontal sinus. The patient underwent chemotherapy and radiation, and she is on follow-up.

In the course of SRY-box transcription factor 6 (SOX6) expression profiling in human embryonic tissue, SOX 6 was found to be highly expressed in the notochord, based on the findings of immunohistochemistry (IHC). Sox6 is also expressed in the neural tube and the distribution of SOX6 is located in the ventral and dorsal zones of the neural tube. In contrast to the findings that SOX6-positive cells were located on the floor plate of the neural tube, OLIG2- and NKX2.2-expressing cells were lacking on the floor plate of the neural tube, and their expression was restricted only to the ventral zone of the neural tube. The expression patterns of SOX9 were similar to those of OLIG2 and NKX2.2 in the neural tube. NKX2.2 and OLIG2 are not expressed in the notochord, but SOX9 and SOX6 are. Because Sox6 is highly expressed in the notochord, the present study investigated whether or not SOX6 is an immunohistochemical marker for the pathologic diagnosis of chordoma, a neoplasm derived from the notochord. IHC revealed that chordoma was strongly positive for SOX6 in two cases of chordoma, one of which occurred in the sacrococcygeal region and another that developed at the base of the skull, suggesting that SOX6 is a useful marker for the histopathologic diagnosis of chordoma.

The homeodomain transcription factor (TF) Nkx2.2 governs crucial cell fate decisions in several developing organs, including the central nervous system (CNS), pancreas, and intestine. How Nkx2.2 regulates unique targets in these different systems to impact their individual transcriptional programs remains unclear. In this issue of Genes & Development Abarinov and colleagues (pp. 490-504) generated and analyzed mice in which the Nkx2.2 SD is mutated and found that the SD is required for normal pancreatic islet differentiation but dispensable for most aspects of neuronal differentiation.

The consolidation of unambiguous cell fate commitment relies on the ability of transcription factors (TFs) to exert tissue-specific regulation of complex genetic networks. However, the mechanisms by which TFs establish such precise control over gene expression have remained elusive-especially in instances in which a single TF operates in two or more discrete cellular systems. In this study, we demonstrate that β cell-specific functions of NKX2.2 are driven by the highly conserved NK2-specific domain (SD). Mutation of the endogenous NKX2.2 SD prevents the developmental progression of β cell precursors into mature, insulin-expressing β cells, resulting in overt neonatal diabetes. Within the adult β cell, the SD stimulates β cell performance through the activation and repression of a subset of NKX2.2-regulated transcripts critical for β cell function. These irregularities in β cell gene expression may be mediated via SD-contingent interactions with components of chromatin remodelers and the nuclear pore complex. However, in stark contrast to these pancreatic phenotypes, the SD is entirely dispensable for the development of NKX2.2-dependent cell types within the CNS. Together, these results reveal a previously undetermined mechanism through which NKX2.2 directs disparate transcriptional programs in the pancreas versus neuroepithelium.

During embryonic spinal cord development, neural progenitor cells (NPCs) generate three major cell lines: neurons, oligodendrocytes, and astrocytes at precise times and locations within the spinal cord. Recent studies demonstrate early astrogenesis in animal models of spina bifida, which may play a role in neuronal dysfunction associated with this condition. However, to date, the pathophysiological mechanisms related to this early astrocytic response in spina bifida are poorly understood. This study aimed to characterize the development of early astrogliosis over time from Pax6+, Olig2+, or Nkx2.2+ NPCs using a retinoic acid-induced spina bifida rat model. At three gestational ages (E15, E17, and E20), spinal cords from fetuses with retinoic acid-induced spina bifida, their healthy sibling controls, or fetuses treated with the vehicle control were analyzed. Results indicated that premature astrogliosis and astrocytic activation were associated with an altered presence of Pax6+, Olig2+, and Nkx2.2+ NPCs in the lesion compared to the controls. Finally, this response correlated with an elevation in genes involved in the Notch-BMP signaling pathway. Taken together, changes in NPC patterning factor expression with Notch-BMP signaling upregulation may be responsible for the altered astrogenesis patterns observed in the spinal cord in a retinoic acid-induced spina bifida model.

Ewing sarcoma (ES) is an aggressive neoplasm with variable morphology. It has no specific immunoprofile or molecular signature. Neither CD99, NKX2.2 nor PAX7 immunoreactivity alone is completely specific, although diagnostic specificity improves when combined. The purpose of the present study was to investigate the immunohistochemical (IHC) expression of PAX7 in a large series of genetically confirmed ES. Existing results for CD99 and NKX2.2 immunoexpression, morphological findings and molecular studies (fusion gene subtypes) were retrieved from a previous study. Survival analyses were performed in cases with available clinical follow-up. PAX7 was positive in 95.5% of ES with diffuse staining (> 50%) in all positive cases and moderate or strong intensity for most cases. Nineteen ES displayed both PAX7 and CD99 immunoreactivity but lacked NKX2.2 immunoexpression. No relationships could be found between PAX7 expression and the histological types or ES gene fusion subtypes. Univariant/multivariate analysis showed that lack of PAX7 and/or NKX2.2 immunoexpression constitute independent poor prognostic factors for progression free survival (PFS) and overall survival (OS). In conclusion, IHC for CD99, NKX2.2, and PAX7 may be useful in daily practice for ES diagnosis, particularly in hospitals lacking facilities for molecular studies. In addition, the combination of strong CD99 membranous positivity and nuclear PAX7 and NKX2.2 immunoreactivity seems to be very reliable for ES diagnosis when supported by a corroborating histomorphologic and clinical picture. Although PAX7 is not entirely specific for ES, it seems to have a more extensive and strong nuclear immunoreactivity than NKX2.2 expression, even in tumors with decalcification artifact. Considering the prognostically significant data herein reported, we strongly recommend validation in prospective ES series that include localized and disseminated tumors.

Ewing sarcoma (ES) is a malignant round cell tumour (MRCT) that usually involves bone and soft tissue of young and paediatric populations. ES of the head and neck region is uncommon. Adamantinoma-like Ewing sarcoma (ALES) is a rare variant of ES that shows complex epithelial differentiation on histopathology and immunohistochemistry (IHC). It demonstrates a t(11;22) translocation and EWSR1- FLI1 fusion. Most documented cases of ALES of the head and neck region were initially misdiagnosed as epithelial tumours. We present a rare case of ALES of the nasal cavity in a young female. The patient subsequently underwent chemotherapy and showed an excellent response. Awareness of this entity is important for pathologists and oncologists due to its distinct therapeutic and prognostic implications. We propose performing upfront NKX2.2 and CD99 IHC studies, as well as other lineage specific IHC markers, in any poorly differentiated MRCT of head and neck region.