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This study aim to identify the clinical risk factors of and to develop a radiomics-based predictive model for early postoperative seizure.We retrospectively assessed 322 operative patients with meningioma who met the inclusion criteria from January 2014 to December 2016 at The First Affiliated Hospital of Wenzhou Medical University. Univariate and multivariate analyses were performed to determine the predictive value of clinical variables. Magnetic resonance imaging (MRI) was performed to obtain the radiomic score (Rscore) for early postoperative seizure. Radiological features were evaluated using the AK software. The minimal redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) methods were used to assess for radiomic features, and the Rscore was obtained based on radiomic characteristics using a specific formula.In total, 260 patients who met the inclusion criteria were finally enrolled in this study. Among them, 20 experienced early postoperative seizure. Logistic regression analysis showed that Rscore was associated with a significantly high risk of seizure (p0.000). Receiver operating characteristic (ROC) curve analysis revealed that the area under the ROC curve of the Rscore was 0.92 (95% confidence interval: 0.853-0.987). The model had a high accuracy for predicting early postoperative seizure.The Rscore was found to be associated with a high risk of early postoperative seizures. Thus, a higher Rscore (-1.644) can identify high-risk patients requiring intensive care.

Aim: This study aimed to identify the independent risk factors of recurrence in patients undergoing primary resection of meningioma and construct a scoring system for the prediction of the risk of postoperative recurrence.Materials and Methods: The clinical data of 591 patients who underwent primary surgical resection for meningioma at the First Affiliated Hospital of Wenzhou Medical University between November 2010 and December 2016 were retrospectively reviewed. The clinical, radiological, and pathological characteristics were evaluated, and the independent risk factors for recurrence were identified via receiver operating characteristic (ROC) curve and logistic analyses. A scoring system that included these independent risk factors was used to construct a risk-predicting model that was evaluated via a ROC curve analysis. The recurrences of different subgroups were observed by Kaplan-Meier's curves.Results: The clinical data of 392 patients with meningioma were used to construct the scoring system. The logistic analysis showed that sex (OR = 2.793, 95% CI = 1.076–7.249, P = 0.035), heterogeneous tumor enhancement (OR = 4.452, 95% CI = 1.714–11.559, P = 0.002), brain invasion (OR = 2.650, 95% CI = 1.043–6.733, P = 0.041), Simpson's removal grade (OR = 5.139, 95% CI = 1.355–19.489, P = 0.016), and pathological grade (OR = 3.282, 95% CI = 1.123–9.595, P = 0.030) were independent risk factors for recurrence. A scoring system was developed and used to divide the patients into the following four subgroups: subgroup 1 with scores of 0–75 (n = 249), subgroup 2 with scores of 76–154 (n = 88), subgroup 3 with scores of 155–215 (n = 46), and subgroup 4 with scores of 216–275 (n = 9). The incidences of recurrence in each subgroup were as follows: subgroup 1, 1.2%; subgroup 2, 5.7%; subgroup 3, 26.1%; and subgroup 4, 66.7% (P < 0.001). The scoring system reliably predicted the postoperative recurrence of meningioma with a high area under the ROC curve.Conclusions: Our scoring system is a simple and reliable instrument for identifying meningioma patients at risk of postoperative recurrence and could help in optimizing individualized clinical treatment.

To date, the management of dopamine agonist (DA)-resistant prolactinomas remains a major clinical problem. Previously, we determined that miRNA-93 expression increases in DA-resistant prolactinomas; however, the role of miRNA-93 in the DA resistance remains largely unexplored. Hence, this study aimed to investigate the susceptibility of tumor cells to cabergoline (CAB) and the autophagy changes in MMQ and GH3 cells after miRNA-93 overexpression or inhibition. We used bioinformatics to identify the potential target of miRNA-93. Subsequently, we analyzed the correlation between miRNA-93 and autophagy-related 7 (ATG7) using protein expression analysis and luciferase assays. Furthermore, the change in the effect of miRNA-93 was measured after ATG7 overexpression. miRNA-93 expression was elevated in DA-resistant prolactinomas, whereas the expression of its identified target, ATG7, was downregulated. miRNA-93 overexpression suppressed the cytotoxic effect of CAB in MMQ and GH3 cells. In contrast, miRNA-93 downregulation enhanced CAB efficiency and promoted cell autophagy, eventually resulting in apoptosis. These results were further confirmed in in vivo xenograft models in nude mice. ATG7 overexpression could reverse the inhibitory effect of miRNA-93 on CAB treatment. Taken together, our results suggest that miRNA-93 mediates CAB resistance via autophagy downregulation by targeting ATG7 and serves as a promising therapeutic target for prolactinoma.

Surgical treatment for cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) is controversial. A subset of CAA-related ICH with associated subdural hemorrhage (SDH) has been reported. This study aimed to evaluate clinical results and surgical outcomes of this type of ICH with associated SDH.Study participants included 98 patients with CAA-related ICH who met Boston criteria. Patients were divided into an SDH group and a control (no SDH) group. Clinical and neuroimaging features and surgical outcomes of the 2 groups were compared.Lobular shape of hematoma was found significantly more often in the SDH group (65.7% [23/35]) compared with the control group (25.4% [16/63]; P0.001). Subarachnoid hemorrhage was found significantly more often in the SDH group (34.3% [12/35]) compared with the control group (7.9% [5/63]; P = 0.001). The rate of postoperative hemorrhage was significantly higher in the SDH group (61.5% [8/13]) than in the control group (16.2% [6/37]; P = 0.006). The frequency of occurrence of postoperative hemorrhage was significantly higher in the SDH group (13/13) than in the control group (6/37; P = 0.017). A good surgical outcome occurred in none (0/12) of the patients in the SDH group, whereas a good surgical outcome occurred in 51.9% (14/27) of patients in the control group (P = 0.006).Patients with CAA-related ICH with associated SDH more frequently have postoperative hemorrhage and have a worse surgical outcome. These findings are useful in choosing therapeutic methods and preoperative planning of surgical strategy.

BACKGROUND Dopamine agonists (DAs) are the first-line treatment for prolactinomas. DAs primarily target the dopamine D2 receptor (D2R). Tumor stem-like cells (TSLCs) are associated with the tolerance to radiotherapy and chemotherapy. TSLCs have also been identified in pituitary adenomas. We aimed to characterize the expression pattern of stem cell markers and D2R in human and rat prolactinomas. MATERIAL AND METHODS Human prolactinoma specimens (n=14) were obtained from patients with surgical resection. The xenograft model of rat prolactinomas was generated by endermically injecting MMQ cells, HE and PRL were confirmed by immunohistochemical staining of tumor sections, and the expression of serum PRL was measured by ELISA. The expression of stem cell markers (CD133, Nestin, Oct4, and Sox2) and D2R in prolactinomas was detected by immunofluorescence. The proportion of CD133-expressing cells after DA treatment was evaluated by flow cytometry in vitro. RESULTS We found that a small subpopulation of cells expressing stem cell markers existed both in human and rat prolactinomas. Furthermore, the CD133-expressing cells showed negative D2R expression. Conversely, the D2R-expressing cells showed negative CD133 expression. The proportion of CD133-expressing cells in surviving tumor cells was significantly increased after DA treatment. CONCLUSIONS Our results confirmed the existence of cells expressing stem cell markers in human and rat prolactinomas. Additionally, the CD133-expressing cells might resist DA therapy due to the lack of D2R expression.

// Sushil Kumar 1 , Bin Lu 2,3 , Updesh Dixit 1 , Sajjad Hossain 4 , Yongzhang Liu 2 , Jing Li 5 , Peter Hornbeck 5 , Weiming Zheng 6 , Adam G. Sowalsky 7 , Leszek Kotula 4 and Raymond B. Birge 1 1 Department of Microbiology, Biochemistry and Molecular Genetics, Cancer Center, Rutgers New Jersey Medical School, Newark, New Jersey, USA 2 Institute of Biophysics, School of Life Sciences, Wenzhou Medical University, Wenzhou, China 3 Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, China 4 Departments of Urology and Biochemistry and Molecular Biology, SUNY Upstate Medical University, New York, NY, USA 5 Cell Signaling Technology, Danvers, MA, USA 6 Department of Neurosurgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China 7 Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA Correspondence to: Raymond B. Birge, email: // Leszek Kotula, email: // Keywords : non-canonical Crk signaling, Abi1, glioblastoma multiformae, cell invasion Received : September 22, 2015 Accepted : September 29, 2015 Published : October 12, 2015 Abstract Crk is the prototypical member of a class of Src homology 2 (SH2) and Src homology 3 (SH3) domain-containing adaptor proteins that positively regulate cell motility via the activation of Rac1 and, in certain tumor types such as GBM, can promote cell invasion and metastasis by mechanisms that are not well understood. Here we demonstrate that Crk, via its phosphorylation at Tyr251, promotes invasive behavior of tumor cells, is a prominent feature in GBM, and correlating with aggressive glioma grade IV staging and overall poor survival outcomes. At the molecular level, Tyr251 phosphorylation of Crk is negatively regulated by Abi1, which competes for Crk binding to Abl and attenuates Abl transactivation. Together, these results show that Crk and Abi1 have reciprocal biological effects and act as a molecular rheostat to control Abl activation and cell invasion. Finally, these data suggest that Crk Tyr251 phosphorylation regulate invasive cell phenotypes and may serve as a biomarker for aggressive GBM.

Hormonal regulation of pituitary gonadotropin gene expression has been attributed to gonadotropin-releasing hormone (GnRH)-mediated stimulation of immediate early gene expression and gonadal steroid interactions with their respective nuclear receptors. A number of orphan nuclear receptors including steroidogenic factor 1, liver receptor homologue 1, dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1, and chicken ovalbumin upstream promoter-transcription factors I/II as well as the GATA family members, GATA2 and GATA4, have also been implicated in transcriptional regulation of the gonadotropin genes. We hypothesized that hormonally mediated changes in these latter transcription factors may provide an additional mechanism for mediating hormonal effects beyond the more classically appreciated pathways. In these studies, we demonstrate significant regulation of orphan nuclear receptor and GATA messenger RNA levels by GnRH, dihydrotestosterone, estradiol, and progesterone in both cultured primary pituitary cells and gonadotrope-derived cell line, LβT2. These results advance our understanding of the complex mechanisms by which GnRH and steroid hormones achieve precise regulation of anterior pituitary function.

Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors are expressed in the hypothalamus, the gonadotrope cells of the anterior pituitary gland, and the gonads, forming an autocrine–paracrine system in these tissues. Within the pituitary, PACAP functions either alone or synergistically with gonadotropin-releasing hormone (GnRH) to stimulate gonadotropin gene expression and secretion. Our goal was to define the hormonal regulation of pituitary PACAP and PACAP receptor (PAC1) gene expression by dihydrotestosterone (DHT), estradiol, and progesterone alone or in conjunction with GnRH. Treatment of adult male rat pituitary cell cultures with DHT or progesterone augmented GnRH-mediated increase in PACAP messenger RNA (mRNA) levels, but neither had an effect when present alone. Conversely, estradiol treatment blunted PACAP gene expression but did not alter GnRH effects on PACAP expression. Expression of PACAP receptor mRNA was decreased by GnRH treatment, minimally increased by DHT treatment, but not altered by the addition of estradiol or progesterone. DHT and GnRH together blunted PACAP receptor gene expression. Taken together, these results suggest that the activity of the intrapituitary PACAP-PAC1 system is regulated via the complex interaction of gonadal steroids and hypothalamic GnRH.

Up-regulation of Notch4 was observed in the endothelial cells in the arteriovenous malformations (AVMs) in mice. However, whether Notch4 is also involved in brain AVMs in humans remains unclear. Here, we performed immunohistochemistry on normal brain vascular tissue and surgically resected brain AVMs and found that Notch4 was up-regulated in the subset of abnormal vessels of the brain AVM nidus, compared with control brain vascular tissue. Two-photon confocal images show that Notch4 was expressed not only in the endothelial but also in the smooth muscle cells of the vascular wall in brain AVMs. Western blotting shows that Notch4 was activated in brain AVMs, but not in middle cerebral artery of normal human brain, which was confirmed by immunostaining. Our findings suggest a possible contribution of Notch4 signalling to the development of brain AVMs in human.

Pituitary apoplexy is a rare disease caused by a sudden hemorrhage into or infarction of the pituitary gland. Its optimal management remains controversial. The aim of this study was to compare the outcomes of surgical and non-surgical treatments for pituitary apoplexy.A systematic literature search was performed of MedLine, EmBase, the Cochrane Library, and the Web of Science for articles published between January 1992 and September 2014. Studies of the outcomes in consecutive patients that compared surgical intervention with non-surgical treatment for pituitary apoplexy were included.Six studies met the inclusion criteria. As compared to the non-surgically treated patients, surgically treated patients had a significantly higher rate of recovery of ocular palsy and visual field (both P0.05). However, there was no significant difference in the recovery of visual acuity and pituitary function (P0.05) between the two groups.The findings of our study suggest that surgical intervention should be advocated for pituitary apoplexy patients with visual field defects and ocular palsy.

Normal sexual development and reproductive function depend on precise temporal and quantitative expression of the pituitary gonadotropins, LH and FSH. LHβ-subunit gene expression is achieved by transcription factors acting at highly conserved and closely spaced cis-elements in the proximal 200 base pairs of the promoter. We now demonstrate that LHβ promoter activity is further regulated by the orphan nuclear receptors, chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and COUP-TFII). These data establish that COUP-TFs are expressed in primary pituitary gonadotropes and two gonadotrope-derived cell lines. COUP-TFs bind to two promoter regions in the LHβ gene which overlap but are distinct from two previously defined cis-elements for another orphan nuclear receptor, steroidogenic factor-1 (SF-1). Transient transfection studies demonstrated that COUP-TFs stimulate LHβ gene promoter activity in the absence of SF-1, but blunt SF-1-mediated stimulation of gene expression in a reporter construct containing both SF-1 cis-elements (GSEs). Evaluation of constructs containing mutations or truncations in the GSEs revealed a complex pattern of activation and inhibition by COUP-TF on this promoter, suggesting multiple mechanisms by which this factor modulates LHβ gene expression. To our knowledge, these data are the first to demonstrate COUP-TF expression and function in pituitary gonadotropes.

Although reproductive aging in women is classically attributed to loss of ovarian follicles, recent data have suggested that the entire hypothalamic-pituitary-ovarian axis undergoes functional changes with time. The aim of this study was to characterize age-related changes in pituitary gene expression for factors with known importance for gonadotroph function, including 1) steroid hormone receptors (Esr and Pgr), 2) orphan nuclear receptors [Nr5a1 (steroidogenic factor-1) and Nr5a2 (liver receptor homologue-1)], and 3) pituitary-derived polypeptides (activin, inhibin, and follistatin), as well as 4) gonadotropin subunits and 5) GnRH receptors. We chose to utilize a middle-aged rat model for these studies. Young (Y; 3-mo-old) and middle-aged (MA; 9- to 12-mo-old) rats were ovariectomized, primed with estradiol, and injected with progesterone to induce an LH surge. The mRNA levels for the gonadotropin subunits and GnRH receptors were decreased in middle-aged females relative to young animals. Nr5a1...

The purpose of this study was to determine the synthetic sites of IgG in the chicken oviduct by localizing IgG gamma-chain mRNA (IgGgamma mRNA)-expressing cells and the effects of estrogen on their population. Paraffin sections of oviducal tissues from laying hens (approximately 57 weeks old) and immature hens (approximately 16 weeks old) with or without diethylstilbestrol (DES) treatment were hybridized by digoxigenin-labeled IgG riboprobes or immunostained for IgG gamma-chain (IgG). Immunoreactive IgG was present in some of the mucosal epithelial cells and the plasma cell-like cells in the stromal connective tissue in all segments of the oviduct. In contrast, IgGgamma mRNA expression was observed only in the plasma cell-like cells in the stromal connective tissues, but not in the cells of mucosal epithelium. In laying hens, the lower end of the oviduct, namely the vagina and uterovaginal junction, contained more IgGgamma mRNA-expressing cells than the other segments. Treatment of immature hens with DES for 3 or 6 days increased the population of both IgGgamma mRNA-expressing cells and IgG-containing cells in the oviducal stroma. These results indicate that IgG is locally produced by plasma cell-like cells in the stroma, but not by the cells of the mucosal epithelium, and estrogen may stimulate the infiltration of IgG-producing plasma cell-like cells into the oviducal stroma.

Bromocriptine, a dopamine agonist (DA), has been used in the treatment of prolactinomas. Recent studies have indicated that dopamine 2 receptor short isoform (D2S) may play an important role in suppressing PRL synthesis and prolactinoma cell growth under DA treatment. In the current study, we investigated the role of D2S in the therapeutic action of bromocriptine in GH3 using both in vitro and in vivo approaches. Infection of adenovirus-D2S increased D2S expression in GH3 cells (P

As endocrinologically active cells, adipocytes are capable of secreting various adipocytokines such as leptin, resistin, and adiponectin to impact metabolic function. Although adipocytes remain to be the primary site of synthesis and secretion, there is now growing evidence that supports the presence of adiponectin and its receptors within the hypothalamic–pituitary–gonadal axis, providing a possible link between obesity and abnormal reproductive physiology. It has been demonstrated that adiponectin may reduce gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus as well as modulate gonadal steroid hormone production. Furthermore, prior data indicate that adiponectin may play a role in decreasing luteinizing hormone secretion from pituitary gonadotropes. We aimed to identify the hormonal regulators of adiponectin and its receptors, AdipoR1 and AdipoR2, in pituitary gonadotropes using immortalized gonadotropic LβT2 cells and primary rat pituitary cells. Our study shows significant alterations in adiponectin expression across the estrous cycle. In addition, we present a novel finding that GnRH suppresses pituitary adiponectin expression via the calcium and protein kinase A intracellular pathways in both cultured rat primary pituitary cells and the LβT2 gonadotrope cell line. The GnRH did not alter expression of the adiponectin receptors, AdipoR1 and AdipoR2, in cultured gonadotropes. Expression of the adiponectin receptors, AdipoR1 and AdipoR2, was not altered by GnRH in cell culture but in vivo or in vitro. Our data suggest that gonadotrope function may be modulated by GnRH-mediated changes in adiponectin expression.

In order to understand the mechanism of human breast cancer we use the growth rates of clonal expansion of intermediate cells and mutation rates as parameters and build two-six stage models to fit the age-specific incidence of breast cancers in the surveillance, epidemiology, and end results (SEER) registry. We propose four types of different mechanisms for the human breast cancer and test those mechanisms by Chi-square test. Our results suggest that loss of functions of instability genes is an early event in the tumorigenesis, which is useful for early diagnosis of breast cancer. The clonal expansion of intermediate cells must depend on the hormone expression level of females, which implies that it may be effective for females to receive hormone blocking therapy for breast cancer before their menopause.

Little is known about the function of microRNAs in prolactinomas treated with bromocriptine. The aim of the study was to explore the microRNAs associated with bromocriptine-treated prolactinomas. Six prolactinoma samples were selected according to whether they received bromocriptine treatment or not before microsurgery, and microRNA expression profiles of bromocriptine-treated and untreated prolactinomas were screened by the miRCURY LNA Array. The differentially expressed microRNAs in microarrays were further validated by stem-loop real-time PCR and subjected to gene ontology analysis and KEGG pathway analysis. In addition, related genes of microRNAs were analyzed by qRT-PCR in 15 prolactinoma samples. The initial analysis by microarrays generated a list of 80 upregulated microRNAs and 71 downregulated microRNAs in treated prolactinomas compared to untreated prolactinomas. miR-206, miR-516b and miR-550 were confirmed to be significantly upregulated, while miR-671-5p was confirmed to be significantly downregulated in treated prolactinomas by qRT-PCR. microRNA-mRNA network analysis integrating GO and KEGG pathway annotation displayed some critical factors. Platelet-derived growth factor α polypeptide (PDGFA) and bone morphogenetic protein 4 (BMP4), were verified to be differentially expressed between the two groups. PDGFA was significantly upregulated in treated prolactinomas, while BMP4 was significantly downregulated in treated prolactinomas. Our study reveals differential expression of microRNAs in prolactinoma after pharmacotherapy. Specific microRNAs may be involved in the inhibition or promotion of prolactinoma tumor growth impacted by bromocriptine pharmacotherapy. PDGFA and BMP4 may be involved in the pharmacotherapy mechanism of prolactinoma.

Nerve growth factor (NGF) can increase expression of dopamine 2 receptors (D2R) in GH3 rat pituitary tumor cells (GH3 cells). As D2R exists in long (D2L) and short (D2S) isoforms, effects of NGF on D2R subtypes have not been accurately evaluated. In this study, we compared mRNA levels of D2R subtypes in GH3 cells treated with or without NGF with real-time RT-PCR. In addition, we also evaluated the relationship between GH3 cell growth after bromocriptine treatment and mRNA levels of D2R subtypes. We found that D2R total, D2L, and D2S mRNA in GH3 cells were significantly increased after NGF treatment, compared with the vehicle group. Moreover, NGF increased the ratio of D2S to D2L. GH3 cell survival rate after bromocriptine treatment was negatively correlated with D2R total mRNA, and D2S may be more potent than D2L in inhibiting cell growth. Cell apoptosis rate was highly elevated in GH3 cells treated with NGF and bromocriptine, compared with the control group or the group treated with NGF or bromocriptine alone. Our data provide preliminary evidence that the effect of NGF was more prominent on expression of D2S than D2L, in addition, D2S might have a greater impact suppressing GH3 cells growth than D2L.

Dopamine receptor agonists (DAs) can reduce hormone release and tumor mass in the majority of prolactinomas, whereas such effects are controversial in clinically nonfunctioning pituitary adenomas (NFPAs). Whether expression of dopamine 2 receptor (D2R) is different in subgroups of NFPAs has not been fully elucidated. We assessed and compared D2R subtype (long: D2L and short: D2S) mRNA levels in subgroups of NFPAs by real-time reverse transcriptase polymerase chain reaction (RT-PCR). For both D2L and D2S mRNA, there were no significant differences among them. Only 21.6% of NFPAs showed relatively high D2R mRNA levels; furthermore, histopathological subtypes of those cases with relatively high D2R expression were gonadotropinomas and null-cell adenomas. These data suggest that DAs are effective only for a small proportion of NFPAs, and relatively high D2R expression may more possibly happen to a subset of gonadotropinomas and null-cell adenomas.

While much work has been conducted regarding the neurogenesis response to traumatic brain injury (TBI) in rodents, it remains largely unknown whether neurogenesis in adult human brain also responds to TBI in a similar manner. Here, we performed immunocytochemistry on 11 brain specimens from patients with traumatic brain injury, who underwent surgical intervention. We found that expression of neural stem/progenitor cell (NSC) protein markers, including DCX, TUC4, PSA-NCAM, SOX2 and NeuroD, was increased in the perilesional cortex of human brain after TBI compared to that of normal brain. Confocal images showed that these NSC proteins were expressed in one single cell. We also found that proliferative markers were expressed in NSC protein-positive cells after TBI, and the number of proliferative NSCs was significantly increased after TBI. Our data suggest that TBI may also induce neurogenesis in human brain.

A role for the Notch signalling pathway in the formation of arteriovenous malformations during development has been suggested. However, whether Notch signalling is involved in brain arteriovenous malformations in humans remains unclear. Here, we performed immunohistochemistry on surgically resected brain arteriovenous malformations and found that, compared with control brain vascular tissue, Notch-1 signalling was activated in smooth muscle and endothelial cells of the lesional tissue. Western blotting showed an activated form of Notch-1 in brain arteriovenous malformations, irrespective of clinical presentation and with or without preoperative embolization, but not in normal cerebral vessels from controls. In addition, the Notch-1 ligands Jagged-1 and Delta-like-4 and the downstream Notch-1 target Hes-1 were increased in abundance and activated in human brain arteriovenous malformations. Finally, increased angiogenesis was found in adult rats treated with a Notch-1 activator. Our findings suggest that activation of Notch-1 signalling is a phenotypic feature of brain arteriovenous malformations, and that activation of Notch-1 in normal vasculature induces a pro-angiogenic state, which may contribute to the development of vascular malformations.

Eyes absent ( Eya ) genes regulate organogenesis in both vertebrates and invertebrates. Mutations in human EYA1 cause congenital Branchio-Oto-Renal (BOR) syndrome, while targeted inactivation of murine Eya1 impairs early developmental processes in multiple organs, including ear, kidney and skeletal system. We have now examined the role of Eya1 during the morphogenesis of organs derived from the pharyngeal region, including thymus, parathyroid and thyroid. The thymus and parathyroid are derived from 3rd pharyngeal pouches and their development is initiated via inductive interactions between neural crest-derived arch mesenchyme, pouch endoderm, and possibly the surface ectoderm of 3rd pharyngeal clefts. Eya1 is expressed in all three cell types during thymus and parathyroid development from E9.5 and the organ primordia for both of these structures failed to form in Eya1 –/– embryos. These results indicate that Eya1 is required for the initiation of thymus and parathyroid gland formation. Eya1 is also expressed in the 4th pharyngeal region and ultimobranchial bodies. Eya1 –/– mice show thyroid hypoplasia, with severe reduction in the number of parafollicular cells and the size of the thyroid lobes and lack of fusion between the ultimobranchial bodies and the thyroid lobe. These data indicate that Eya1 also regulates mature thyroid gland formation. Furthermore, we show that Six1 expression is markedly reduced in the arch mesenchyme, pouch endoderm and surface ectoderm in the pharyngeal region of Eya1 –/– embryos, indicating that Six1 expression in those structures is Eya1 dependent. In addition, we show that in Eya1 –/– embryos, the expression of Gcm2 in the 3rd pouch endoderm is undetectable at E10.5, however, the expression of Hox and Pax genes in the pouch endoderm is preserved at E9.5-10.5. Finally, we found that the surface ectoderm of the 3rd and 4th pharyngeal region show increased cell death at E10.5 in Eya1 –/– embryos. Our results indicate that Eya1 controls critical early inductive events involved in the morphogenesis of thymus, parathyroid and thyroid.