Astrocyte heterogeneity is an increasingly prominent research topic, and studies in the brain have demonstrated substantial variation in astrocyte form and function, both between and within regions. In contrast, retinal astrocytes are not well understood and remain incompletely characterized. Along with optic nerve astrocytes, they are responsible for supporting retinal ganglion cell axons and an improved understanding of their role is required. We have used a combination of microdissection and Ribotag immunoprecipitation to isolate ribosome-associated mRNA from retinal astrocytes and investigate their transcriptome, which we also compared to astrocyte populations in the optic nerve. Astrocytes from these regions are transcriptionally distinct, and we identified retina-specific astrocyte genes and pathways. Moreover, although they share much of the \"classical\" gene expression patterns of astrocytes, we uncovered unexpected variation, including in genes related to core astrocyte functions. We additionally identified the transcription factor Pax8 as a highly specific marker of retinal astrocytes and demonstrated that these astrocytes populate not only the retinal surface, but also the prelaminar region at the optic nerve head. These findings are likely to contribute to a revised understanding of the role of astrocytes in the retina.

UNASSIGNED: Small cell lung cancer (SCLC) shows poor prognosis since it metastasizes widely at early stage. Paired box gene (PAX) 8 is a transcriptional factor of PAX family, of which the expression in lung cancer is a controversial issue, and its prognostic value of PAX8 in SCLC is still unclear.
UNASSIGNED: Overall, 184 subjects who were pathologically diagnosed with SCLC were enrolled in the study. Immunohistochemical analysis of PAX8 and Ki-67 were performed. The correlations between PAX8 expression and clinical features or Ki-67 index were further analyzed. Subsequently, an analysis of the association between PAX8, stage, Ki-67 status, and overall survival (OS) were performed in 169 subjects with follow-up information.
UNASSIGNED: PAX8 was positive in 53.8% (99/184) SCLC specimens. The positive rate is significantly higher in extensive-stage specimens (61.0%) than in limited-stage specimens (45.24%). PAX8 expression is positively correlated with Ki-67 index (P = 0.001) while negatively correlated with OS (HR = 3.725, 95% CI 1.943-7.139, P＜0.001). In combination groups, the PAX8 negative and limited stage group had the most promising OS.
UNASSIGNED: PAX8 expression rate in SCLC specimens is not low. It has prognostic value in small cell lung cancer.

Anaplastic thyroid carcinoma (ATC) is a highly aggressive form of thyroid cancer with poor prognosis. Differentiated thyroid carcinoma (DTC) including papillary thyroid carcinoma (PTC) is more common and known to have a favorable outcome after treatment. Here, we report a case of a 59-year-old lady with a long-standing goiter presenting with a discharging anterior neck mass. Fine-needle aspiration cytology (FTAC) of the mass resulted with malignant cells. She underwent surgery, and histopathological examination revealed both ATC and PTC features. Mutation analysis was also performed, and results were positive for BRAF 600VE mutation. She received radiotherapy and also chemotherapy post-surgery. Treatment was well tolerated. The relatively favorable survival of this patient may suggest that synchronous ATC and DTC may have better prognosis than ATC alone. The objective of this article is to report the unique clinical presentation and favorable prognosis with combined treatment modalities.

Female urethral adenocarcinoma has attracted attention as a rare tumor type based on its differential pathogenesis from its male counterpart. However, to date, our knowledge concerning its immunohistochemical and morphological characteristics remains limited due to the small number of cases studied. In this study, nine consecutive cases of female urethral adenocarcinoma were used for immunohistochemical and morphological characterization of the tumor based on semi-comprehensive immunohistochemical analysis and detailed morphological evaluations. Our immunohistochemical assay revealed two subtypes of female urethral adenocarcinoma with distinctive staining patterns: the CDX2- and PAX8-expressing subtypes. The former stained positive for other intestinal markers (e.g., HNF4α and TFF1) as well (7 of 7 cases); the latter stained negative for these intestinal markers (0 of 2 cases) but stained positive for clear cell carcinoma markers (e.g., Napsin A and HNF1β) (2 of 2 cases). Regarding cytokeratins, the former displayed a CK7- and CK20-positive immunoprofile (7 of 7 cases); the latter exhibited a CK7-positive and CK20-negative immunoprofile (2 of 2 cases). Morphologically, CDX2- and PAX8-expressing subtypes resembled intestinal-type adenocarcinoma and clear cell carcinoma (occurring in gynecological organs), respectively. The semi-comprehensive immunoprofiling data presented in this study can potentially contribute to the correct diagnosis of this rare tumor type. Finally, our study represents an important basis for future investigations aiming to further elucidate the details and origin of female urethral adenocarcinoma, and it can potentially contribute to developing diagnostic and therapeutic strategies for treating this malignancy.

BACKGROUND: Histomorphological differentiation between pancreatic serous cystadenoma (SCA) and clear cell renal cell carcinoma (RCC) can be challenging. We aimed to study Paired box 8 protein (Pax8) expression profile in cytologic and surgical specimens with pancreatic SCA to assess its utility as a differentiating marker from clear cell RCC.
METHODS: We characterized Pax8 immunohistochemistry in 33 patients with pancreatic SCA (23 surgical resections and 10 cytology specimens). Nine cytology specimens from metastatic clear cell RCC involving pancreas were used as control tissue. Electronic medical records were reviewed to retrieve clinical information.
RESULTS: All 10 pancreatic SCA cytology specimens, and 16 of 23 pancreatic SCA surgical resections showed absent Pax8 immunostaining, while the remaining 7 surgical resection specimens showed 1%-2% immunoreactivities. Islet and lymphoid cells adjacent to the pancreatic SCA expressed Pax8. In contrast, the proportion of Pax8 immunoreactivity ranged from 50 to 90% (average of 76%) in nine cases of metastatic clear cell RCC involving pancreas. Using a 5% immunoreactivity cutoff, all cases of pancreatic SCA are interpreted as negative for Pax8 immunostains while all cases of metastatic clear cell RCC involving pancreas are interpreted as positive for Pax8 immunostains.
CONCLUSIONS: These results suggest that Pax8 immunohistochemistry staining can be a useful adjunct marker to differentiate pancreatic SCA from clear cell RCC in clinical practice. To the best of our knowledge, this is the first large-scale study of Pax8 immunostaining on surgical and cytology specimens with pancreatic SCA.

The transcription factors MECOM, PAX8, SOX17 and WT1 are candidate master regulators of high-grade serous \'ovarian\' cancer (HGSC), yet their cooperative role in the hypothesized tissue of origin, the fallopian tube secretory epithelium (FTSEC) is unknown. We generated 26 epigenome (CUT&TAG, CUT&RUN, ATAC-seq and HiC) data sets and 24 profiles of RNA-seq transcription factor knock-down followed by RNA sequencing in FTSEC and HGSC models to define binding sites and gene sets regulated by these factors in cis and trans. This revealed that MECOM, PAX8, SOX17 and WT1 are lineage-enriched, super-enhancer associated master regulators whose cooperative DNA-binding patterns and target genes are re-wired during tumor development. All four TFs were indispensable for HGSC clonogenicity and survival but only depletion of PAX8 and WT1 impaired FTSEC cell survival. These four TFs were pharmacologically inhibited by transcriptional inhibitors only in HGSCs but not in FTSECs. Collectively, our data highlights that tumor-specific epigenetic remodeling is tightly related to MECOM, PAX8, SOX17 and WT1 activity and these transcription factors are targetable in a tumor-specific manner through transcriptional inhibitors.

Renal cell carcinoma (RCC) is common cancer derived from the renal epithelium. One of the rarest cases of RCC is sarcomatoid RCC (sRCC). The occurrence of sRCC in animals is not clearly demonstrated.
This study aimed to observe the clinicopathological characteristics of sRCC in animals from East Java, Indonesia, from 2017 to 2022.
This study used patients who were histopathologically diagnosed with sRCC in our laboratory from 2017 to 2022. The data on the clinical characteristics of animals, hematology, serology, histopathology, and immunohistochemistry (IHC) were retrieved and tabulated. The data were qualitatively and quantitatively analyzed using a simple descriptive method and Statistical Package for the Social Sciences version 26, respectively.
Fourteen cases of sRCC in animals have been identified in this study. It was found in rodents, dogs, and cats. sRCC predominantly occurred in rodents (57.14%) without specific clinical signs. The common histopathological findings of sRCC were epithelial renal cells transition into elongated atypical spindle cells. In addition, other histopathological patterns of a renal epithelial cell such as clear cell, tubule-cystic, and papillary also have been found. IHC by using antibodies demonstrates that PAX8 is expressed on sRCC tissue samples 92.85% (13/14 samples). Hence, PAX8 could be used as a supporting method for establishing the diagnosis of sRCC in animals. Hematology and serological tests did not correlate to the type of sRCC either pure sRCC or dedifferentiated sRCC. sRCC results in hypercreatinemia in rodents and dogs.
This study shows that the incidence of sRCC in animals is rare. Animals with sRCC did not show any specific clinical signs. The histopathological finding is quite difficult to be differentiated from the other RCC. PAX8 expression on renal tissue samples is useful in supporting the diagnosis of sRCC in animals.

Paired box 8 (PAX8) mutations are an established genetic cause of congenital hypothyroidism (CH). The majority of these mutations are found in the protein-coding exons of the gene. The proband, a 3-yr-old girl, had tetralogy of Fallot and polydactyly soon after birth. She was diagnosed with CH in the newborn screening for CH. She had a high serum TSH level (239 mU/L) and low free T4 level (0.7 ng/dL). Ultrasonography revealed thyroid hypoplasia. We performed array comparative genomic hybridization because the patient exhibited a variety of symptoms across multiple organ systems. The analysis revealed a novel heterozygous deletion that spanned a 15.2 Mb region in 2q12.3q14.3 (GRCh37; chr2:109,568,260-124,779,449). There were 71 protein-coding genes in this region, including two genes (PAX8 and GLI2) associated with congenital endocrine disorders. The common clinical features of the two previously reported patients with a total PAX8 deletion and our case were CH, short stature and intellectual disability, but the severity of hypothyroidism and other clinical features were variable. In conclusion, we describe a syndromic CH patient with a novel 2q12.3q14.3 deletion involving PAX8. Patients with CH, whose unifying diagnosis is not obvious, could have a genomic deletion involving PAX8.

Paired box transcription factor 8 (PAX8) is essential for thyroid organogenesis and development. Heterozygous pathogenic variants of PAX8 typically cause congenital hypothyroidism (CH) due to thyroid hypoplasia. Additionally, pathogenic PAX8 variants have been identified in patients with gland in situ (GIS). This study was conducted to analyze the in vitro functional consequences of four PAX8 variants (p.D94N, p.E90del, p.V58I, and p.L186Hfs*22) previously identified in patients with CH and GIS. The transcriptional activity of PAX8 variants on the thyroglobulin (TG) promoter was assessed in a luciferase reporter assay. The levels of transcriptional activity on the TG promoter of p.E90del and p.L186Hfs*22 were significantly reduced, whereas p.D94N and p.V58I showed residual activation. In addition, a dominant negative effect on the wild-type (WT) was not detected in any PAX8 variant using a luciferase reporter assay. Two PAX8 variants (p.E90del and p.L186Hfs*22) may be pathogenic causes of CH with GIS.

PAX8 is a transcription factor that is expressed in the thyroid gland and kidneys. Monoallelic loss-of-function PAX8 variants cause congenital hypothyroidism (CH), and urogenital malformations are infrequent complications seen in less than 10% of PAX8 variant carriers. Herein, we report the case of a 3-yr-old female patient with CH who was diagnosed during newborn screening. She was treated with levothyroxine, and she showed normal growth and development at a minimal dose (0.7 µg/kg/d of levothyroxine at 3 yr of age). At 5 mo of age, she visited an emergency department for fever and was incidentally found to have differently sized kidneys by ultrasonography, which was subsequently diagnosed as unilateral multicystic dysplastic kidney. Her serum creatinine and cystatin C levels were normal. Next-generation sequencing-based genetic analysis revealed that the patient was heterozygous for a PAX8 frameshift variant (p.Thr320ProfsTer106) and a DUOX2 missense variant (p.Arg885Gln). Our patient is the first truncating PAX8 variant carrier to have a urogenital malformation with CH. Genetic analysis for PAX8 should be considered in patients with CH and urogenital malformations.