Pituitary Transcription Factor Research Articles

How to standardize the diagnostic approach to pituitary neuroendocrine tumors.

Pituitary tumors present heterogeneous biochemical, clinico-radiological, and histological features. Although histologically benign, a non-negligible number of cases present an unpredictable aggressive behavior with local invasiveness, partial/complete resistance to treatment and/or recurrence after surgery, and, rarely, metastasize, overall leading to a significant increase of morbidity, and, thus, requiring skilled multidisciplinary management in referral Centers. Histopathological diagnosis is essential to stratify cancer patient risk and uniform follow-up among Centers. Classification of pituitary neoplasia is continuously evolving in relation to the increased knowledge of mechanisms underlying adenohypophyseal cell tumorigenesis, and the attempts of combining clinico-radiological, biochemical, intraoperative, histological, and molecular elements, with the aim of identifying aggressive forms through. An integrated standardized histopathological report has been proposed in 2019 by the European Pituitary Pathology Group, based on the indications of the 2017 WHO classification of pituitary tumors. The last edition of the WHO Classification of Central Nervous System Tumors and of Endocrine and Neuroendocrine Tumors brought substantial novelties: 1) the replacement of the term "adenoma" with "Pituitary Neuroendocrine Tumor" (PitNET), and of "carcinoma" with "metastatic PitNET," and the consequent ICD-11 recoding from benign to malignant disease; and 2) the pivotal role of lineage restricted pituitary transcription factors for histological typing and subtyping. However, this approach does not reflect the spectrum of tumor phenotypes based on hormone secretion, nor include molecular features. Efforts of interdisciplinary groups of pituitary experts should be strongly encouraged to better understand factors involved in PitNETs evolution and, consequently, standardize diagnosis and reporting based on the most recent knowledges, essential to stratify cancer patient risk and uniform follow-up among centers.

The Musashi RNA binding proteins direct the translational activation of key pituitary mRNAs

The pituitary functions as a master endocrine gland that secretes hormones critical for regulation of a wide variety of physiological processes including reproduction, growth, metabolism and stress responses. The distinct hormone-producing cell lineages within the pituitary display remarkable levels of cell plasticity that allow remodeling of the relative proportions of each hormone-producing cell population to meet organismal demands. The molecular mechanisms governing pituitary cell plasticity have not been fully elucidated. Our recent studies have implicated a role for the Musashi family of sequence-specific mRNA binding proteins in the control of pituitary hormone production, pituitary responses to hypothalamic stimulation and modulation of pituitary transcription factor expression in response to leptin signaling. To date, these actions of Musashi in the pituitary appear to be mediated through translational repression of the target mRNAs. Here, we report Musashi1 directs the translational activation, rather than repression, of the Prop1, Gata2 and Nr5a1 mRNAs which encode key pituitary lineage specification factors. We observe that Musashi1 further directs the translational activation of the mRNA encoding the glycolipid Neuronatin (Nnat) as determined both in mRNA reporter assays as well as in vivo. Our findings suggest a complex bifunctional role for Musashi1 in the control of pituitary cell function.

Clinical and Pathological Features of Pit1/SF1 Multilineage Pituitary Neuroendocrine Tumor.

Lineage-based classification has critical clinical implications in pituitary neuroendocrine tumor (PitNET). As the most prevalent subtype of multilineage PitNET, PitNET originating from both pituitary-specific positive transcription factor 1 (Pit1) and steroidogenic factor-1 (SF1) lineages (Pit1/SF1-adenoma) is expected to exhibit rich and varied clinical behaviors. A comprehensive understanding of the clinical and pathological characteristics of Pit1/SF1-adenoma will provide mechanistic insight and influence the prognosis and treatment of PitNET. A retrospective study was conducted by reviewing 57 cases of Pit1/SF1-adenoma between 2018 and 2022. We also included 88 cases of PitNET arising from Pit1 cell lineage (Pit1-adenoma) and 70 cases of PitNET arising from SF1 cell lineage (SF1-adenoma) as controls. Comprehensive data, including demographic, symptom, endocrinal, radiological, surgical, pathological, and prognostic information, were systematically collected. All specimens were immunostained for pituitary transcription factors (PTFs) and pituitary hormones. The detection rate was 8.0% for Pit1/SF1-adenoma within PitNET surgical specimens. Pit1/SF1-adenoma displayed a male predominance, with the mean diagnosis age falling between Pit1-adenoma and SF1-adenoma. The endocrine activity of Pit1/SF1-adenoma was lower than Pit1-adenoma but higher than SF1-adenoma. Pit1/SF1-adenoma had a higher incidence of cavernous sinus invasion (56.1%) than both Pit1-adenoma (38.6%, P = .039) and SF1-adenoma (27.1%, P = .001). Furthermore, Pit1/SF1-adenoma showed more postoperative complications than Pit1-adenoma (29.8% vs 8.0%, P = .001). Nonfunctional Pit1/SF1-adenoma had a higher radiological tumor recurrence rate than nonfunctional SF1-adenoma (34.8% vs 10.9%, P = .021). Notably, the immunostaining pattern was diverse in Pit1/SF1-adenoma, with various combinations of staining intensity for PTFs and 15 combinations for 6 pituitary hormones. Intriguingly, various PTFs combinations had no different impact on the outcome of Pit1/SF1-adenoma. Pit1/SF1-adenoma represents a unique pathological subtype of PitNET, characterized by distinctive clinical behaviors. Identifying Pit1/SF1-adenoma can facilitate more precise management of PitNET by the practical use of Pit1/SF1 immunostaining.

FSH-producing pituitary neuroendocrine tumor as a cause of ovarian hyperstimulation syndrome.

Functioning gonadotroph tumors are rare neoplasms that can cause ovarian hyperstimulation syndrome (OHSS) in women of reproductive age. Here, we present a case of a follicle-stimulating hormone (FSH)-producing pituitary neuroendocrine tumor (PitNET) with irregular menstrual cycles and OHSS in a Japanese woman. A 34-year-old woman with bilateral multi-cystic ovarian mass was referred to our hospital for ovarian surgery. The imaging feature of magnetic resonance imaging (MRI) of the ovary and elevated estradiol levels with normal FSH and low luteinizing hormone (LH) levels led us to suspect the presence of a functioning gonadotroph PitNET. MRI revealed a 19-mm pituitary tumor, and increased tracer uptake was observed in the pituitary lesion on 111In-pentetreotide scintigraphy. Transsphenoidal tumor resection resulted in the resolution of the ovarian enlargement, normalization of her menstrual cycles, and spontaneous pregnancy. Immunohistochemistry (IHC) of the resected tumor for pituitary transcription factors, including steroidogenesis factor 1 (SF1) and estrogen receptor alpha, demonstrated positive immunoreactivity, whereas IHC for pituitary-specific positive transcription factor 1 was negative, suggesting that the tumor belonged to the SF1 lineage of PitNETs (gonadotroph tumor). The tumor cells showed positive expression of FSHβ, while LHβ was mostly negative. Consistent with the high pituitary tumor uptake observed on 111In-pentetreotide scintigraphy, the pituitary tumor showed positive expression of somatostatin receptor 2A. Detailed clinical and histological evaluations will provide useful information to understand these rare functioning gonadotroph tumors better. Functioning gonadotroph tumors are very rare neuroendocrine tumors of pituitary origin. Women of reproductive age presenting with bilateral multi-cystic ovarian enlargement, irregular menstrual cycles, and hyperestrogenemia under unsuppressed follicle-stimulating hormone (FSH) levels should be evaluated for FSH-producing tumor. Raising awareness of OHSS due to functioning gonadotroph tumors is crucial to prevent unnecessary ovarian surgery. Comprehensive histological analysis may provide useful information to better understand the characteristics of functioning gonadotroph tumors.

The clinical presentation of PIT1 positive pituitary neuroendocrine tumor immunonegative for growth hormone, prolactin, and thyroid stimulating hormone with analysis of clinical and immunostaining dissociation

BackgroundPIT1 is a pituitary transcription factor that is associated with either growth hormone (GH), prolactin (PRL), or thyroid-stimulating hormone (TSH) production. However, PIT1-positive pituitary neuroendocrine tumors (PitNETs) are occasionally immunonegative for GH, PRL, and TSH. This paper describes the clinical presentation of PIT1 positive however immunonegative PitNETs. MethodsWe conducted a retrospective analysis, identifying 228 PIT1-positive PitNET patients between 2017 and 2022. Out of these, ten (4%) tested negative for GH, PRL, and TSH. Functioning PitNETs were defined as those causing hormonal excess symptoms or hormonal overproduction. ResultsAs for 10 patients immunonegative for all three hormones however PIT1-positive, the mean ( ± standard deviation) age was 46 ± 13 years with 70% women. Six patients exhibited signs of excess GH or PRL, and three had visual problems. Additionally, one patient had secondary hypothyroidism and adrenal insufficiency resulting from the mass effect. All tumors were macroadenoma, with a median volume of 2.1 cm3 (range, 0.8–17.5 cm3). Gross total resection was attained in six patients by trans-sphenoidal surgery. Postoperatively, eight patients experienced clinical improvement: three in vision, two in amenorrhea, two in headache, and one in acromegaly symptoms. Biochemical improvement was observed in six patients, with all experiencing remission in hormonal excess and one showing improvement in secondary hypothyroidism. Stereotactic radiosurgery was performed in three patients. ConclusionsPatients with functioning PitNETs may exhibit PIT1 staining without GH, PRL, or TSH staining. Hormonally active tumors exist in this patient population; therefore, close endocrine follow-up is necessary despite the lack of staining for GH, PRL, and TSH.

Cytodifferentiation of pituitary tumors influences pathogenesis and cavernous sinus invasion.

Pituitary tumors (PTs) continue to present unique challenges given their proximity to the cavernous sinus, whereby invasive behavior can limit the extent of resection and surgical outcome, especially in functional tumors. The aim of this study was to elucidate patterns of cavernoinvasive behavior by PT subtype. A total of 169 consecutive first-time surgeries for PTs were analyzed; 45% of the tumors were functional. There were 64 pituitary transcription factor-1 (PIT-1)-expressing, 62 steroidogenic factor-1 (SF-1)-expressing, 38 T-box transcription factor (TPIT)-expressing, and 5 nonstaining PTs. The gold standard for cavernous sinus invasion (CSI) was based on histopathological examination of the cavernous sinus medial wall and intraoperative exploration. Cavernous sinus disease was present in 33% of patients. Of the Knosp grade 3 and 4 tumors, 12 (19%) expressed PIT-1, 7 (11%) expressed SF-1, 8 (21%) expressed TPIT, and 2 (40%), were nonstaining (p = 0.36). PIT-1 tumors had a significantly higher predilection for CSI: 53% versus 24% and 18% for TPIT and SF-1 tumors, respectively (OR 6.08, 95% CI 2.86-13.55; p < 0.001). Microscopic CSI-defined as Knosp grade 0-2 tumors with confirmed invasion-was present in 44% of PIT-1 tumors compared with 7% and 13% of TPIT and SF-1 tumors, respectively (OR 11.72, 95% CI 4.35-35.50; p < 0.001). Using the transcavernous approach to excise cavernous sinus disease, surgical biochemical remission rates for patients with acromegaly, prolactinoma, and Cushing disease were 88%, 87%, and 100%, respectively. The granule density of PIT-1 tumors and corticotroph functional status did not influence CSI. The likelihood of CSI differed by transcription factor expression; PIT-1-expressing tumors had a higher predilection for invading the cavernous sinus, particularly microscopically, compared with the other tumor subtypes. This elucidates a unique cavernoinvasive behavior absent in cells from other lineages. Innovative surgical techniques, however, can mitigate tumor behavior and achieve robust, reproducible biochemical remission and gross-total resection rates. These findings can have considerable implications on the surgical management and study of PT biology and behavior.

THU010 A Case Of Cushing's Disease Due To T-pit Positive, ACTH Negative Aggressive Corticotroph Pituitary Adenoma

Abstract Disclosure: C. Gopinath: None. P. Pagadala: None. C. Choudhary: None. D.R. Tilden: None. Introduction: The 2017 WHO classification of Pituitary Adenomas utilizes pituitary transcription factors for its classification system. It can be helpful in identifying cell lineages in adenomas without expression of pituitary hormones. We describe a case of recurrent Cushing’s disease due to an ACTH negative, elevated Ki-67, TPIT positive aggressive corticotroph adenoma. Case report: A 54-year-old male presented with c/o diplopia, fatigue, decreased sexual drive. MRI brain showed a 2.4 x 1.4 x 1.6 cm sellar mass with suprasellar extension, displacement of the optic chiasm, extension into the left cavernous sinus. Hormonal work up showed evidence of central hypothyroidism (free T4- 04 ng/dl(0.6-1.6 NG/dl), TSH- 0.08 MCU/ml(0.35-5.00 MCU/ML) low testosterone (76 ng/dL(270-1070 NG/DL)),random cortisol of 20.1mcg/dL( 5.0-20.0 MCG/DL), ACTH- 136 pg/ml(7-63 pg/ml). Patient underwent transsphenoidal surgery (TSS). Pathology showed a pituitary adenoma of 1.5 cm with conspicuous mitoses and elevated Ki67 proliferation index (range- 15-35%). Immunohistochemistry was positive for prolactin; synaptophysin and negative for ACTH, GH, FSH, LH, TSH. Transcription factors for T-pit, Pit-1 and SF-1 were not assessed. Diagnosis of non-functioning adenoma was made. Repeat MRI showed residual tumor and due to elevated Ki-67, radiation therapy was recommended which was received at an outside hospital. 2.5 years later he was readmitted with profound hypokalemia, metabolic alkalosis and altered mental status. He appeared Cushingoid with facial plethora, moon facies, dorsocervical fat pad and violaceous striae on the abdomen. Dexamethasone suppression testing revealed elevated cortisol of 26.7 mcg/dl, AM cortisol -44.7mcg/dl (6.7-22.6mcg/dl),ACTH-280 pg/mL(7-63 pg/mL),24 hour urine free cortisol was elevated 2065 mcg/24 hour(3.5-45 mcg/24 hr). Given initial negative ACTH staining on the macroadenoma, there was concern for ectopic ACTH given acute presentation and absence of growth on the MRI compared to post radiation scans. IPSS was pursued which showed central ACTH source. Given stable size of residual tissue post radiation and location on MRI neurosurgery recommended against repeat surgery at this time. Patient was started on medical treatment for hypercortisolism with ketoconazole but had elevated liver enzymes limiting dose increase. Clinically patient continued to decline. Given significantly elevated cortisol with high risk of infectious and thrombotic events, poor short term outcomes decision was made for b/l adrenalectomy which he underwent successfully. Immunostains were ordered on the original adenoma resected and showed strong positivity for TPIT. Conclusion: Immunohistochemistry is an important step to aid classification of pituitary adenoma. Management of aggressive corticotroph adenoma with high ki-67 index can be a therapeutic challenge. Presentation: Thursday, June 15, 2023

Somatostatin receptor expression and clinical outcome of multilineage pituitary tumours expressing PIT1 and SF1.

The application of transcription factor immunohistochemistry to pituitary neuroendocrine tumour (PitNET) assessment has allowed identification of tumours that do not conform to a single lineage. Multilineage pituitary transcription factor 1 (PIT1) and steroidogenic factor 1 (SF1) PitNETs are a rare and relatively newly described tumour subtype. These tumours express both transcription factors and may also express combinations of hormones corresponding to both lineages. Histological and clinical characteristics can vary, and overall clinical behaviour and prognosis is not known. We describe the clinical outcomes and somatostatin receptor status (SSTR) of a series of nine cases identified from our cohort of pituitary tumours at Westmead Hospital. Eight PitNETs (88.9%) expressed growth hormone and caused acromegaly at presentation. Of the seven macrotumours that caused acromegaly, one had cavernous sinus invasion. The Ki-67 labeling index score ranged from 0.6% to 3.6%. About 88% of tumours that secreted excess growth hormone exhibited strong immunostaining for SSTR 2 and all tumours displayed weak immunoreactivity for SSTR5. In 62.5% of patients with acromegaly, cure was achieved after surgical resection. Somatostatin receptor ligands resulted in clinical remission in cases where medical treatment was initiated. There was no new tumour recurrence or regrowth over an overall mean follow-up period of 62.5 months.

Plurihormonal Pituitary Neuroendocrine Tumours - A Single Centre Experience.

Introduction. Plurihormonal pituitary neuroendocrine tumours (PitNET)/adenomas are pituitary neuroendocrine tumours composed of monomorphous cell populations expressing anterior pituitary transcription factors and/or hormones belonging to more than one cell lineage. Studies dedicated to plurihormonal tumours are rare and quite heterogenous with their results, bearing in mind changes in diagnostic criteria and inconsistent use of antibodies for anterior pituitary transcription factors in the diagnostic immunohistochemical panel. Material and Methods. We retrospectively analysed all patients surgically treated for PitNETs from 2016 to July 2022 in a tertiary healthcare institution. All tumours previously diagnosed PitNETs with the word "plurihormonal" were re-examined and potentially re-classified, according to 2022 WHO classification of endocrine tumours. Results. Among 721 patients surgically treated for PitNET in 5.5 years period, the diagnosis of plurihormonal PitNET was established in 11 tumours (1.3%). All tumours showed diffuse and intensive positivity for anterior pituitary transcription factors PIT1 and SF1. Clinically, all patients presented with acromegaly. Conclusions. Retrospective studies related to newly defined plurihormonal PitNETs with a reassessment of diagnoses are necessary due to their rarity and ambition to investigate their origin and biological behaviour. The fact that the majority of plurihormonal PitNETs are clinically presented with acromegaly and show simultaneous positivity to PIT1 and SF1 transcription factors deserve special attention and need for further research in larger cohorts of these exceptional tumours.

Tumor immune microenvironment in pituitary neuroendocrine tumors (PitNETs): increased M2 macrophage infiltration and PD-L1 expression in PIT1-lineage subset.

Tumor immune microenvironment in pituitary neuroendocrine tumors (PitNETs) and application of current immunotherapy for refractory PitNETs remains debated. We aim to evaluate the immune landscape in different lineages of PitNETs and determine the potential role of pituitary transcription factors in reshaping the tumor immune microenvironment (TIME), thus promoting the application of current immunotherapy for aggressive and metastatic PitNETs. Immunocyte infiltration and expression patterns of immune checkpoint molecules in different lineages of PitNETs were estimated via in silico analysis and validated using an IHC validation cohort. The correlation between varying immune components with clinicopathological features was assessed in PIT1-lineage PitNETs. Transcriptome profiles from 210 PitNETs/ 8 normal pituitaries (NPs) and immunohistochemical validations of 77 PitNETs/6 NPs revealed a significant increase in M2-macrophage infiltration in PIT1-lineage PitNETs, compared with the TPIT-lineage, SF1-lineage subsets and NPs. While CD68 + macrophage, CD4 + T cells, and CD8 + T cells were not different among them. Increased M2-macrophage infiltration was associated with tumor volume (p < 0.0001, r = 0.57) in PIT1-lineage PitNETs. Meanwhile, differentially expressed immune checkpoint molecules (PD-L1, PD1, and CTLA-4) were screened and validated in IHC cohorts. The results showed that PD-L1 was highly expressed in PIT1-lineage subsets, and PD-L1 overexpression showed a positive correlation with tumor volume (p = 0.04, r = 0.29) and cavernous sinus invasion (p < 0.0001) in PIT1-lineage PitNETs. PIT1-lineage PitNETs exhibit a distinct immune profile with enrichment of M2 macrophage infiltration and PD-L1 expression, which may contribute to its clinical aggressiveness. Application of current immune checkpoint inhibitors and M2-targeted immunotherapy might be more beneficial to treat aggressive and metastatic PIT-lineage PitNETs.

Multilineage Pituitary Neuroendocrine Tumors (PitNETs) Expressing PIT1 and SF1.

PitNETs are usually restricted in their cytodifferentiation to only one of 3 lineages dictated by expression of the pituitary transcription factors (TFs) PIT1, TPIT, or SF1. Tumors that show lineage infidelity and express multiple TFs are rare. We searched the pathology files of 4 institutions for PitNETs with coexpression of PIT1 and SF1. We identified 38 tumors in 21 women and 17 men, average age 53 (range 21-79) years. They represented 1.3 to 2.5% of PitNETs at each center. Acromegaly was the presentation in 26 patients; 2 had central hyperthyroidism associated with growth hormone (GH) excess and one had significantly elevated prolactin (PRL). The remainder had mass lesions with visual deficits, hypopituitarism, and/or headaches. Tumor size ranged from 0.9 to 5cm; all 7 lesions smaller than 1cm were associated with acromegaly. Larger lesions frequently invaded the cavernous sinuses. Four cases represented a second attempt at surgical resection. PIT1 was usually diffusely positive but 5 cases had variable (patchy or focal) staining. SF1 reactivity was variable in intensity but diffuse in all but 2 cases. GATA3 data, available in 14 cases, identified diffuse positivity in 5 and focal staining in 1. GH was expressed in all but 5 tumors, PRL and thyrotropin (TSH) were expressed in 14 and 13, respectively, follicle-stimulating hormone (FSH) in 11 of 18, and luteinizing hormone (LH) in 4 of 17. Keratin staining patterns were diffuse perinuclear/membranous in 27, variable perinuclear in 4, and negative in 3; scattered fibrous bodies were seen in 5 and diffuse fibrous bodies in 1. Ki67 labeling index ranged from < 1 to 7.9%. In 3 cases, these tumors represented one of multiple synchronous PitNETs; a separate corticotroph tumor was seen in 2 patients and one patient had 2 additional discrete lesions, a sparsely granulated lactotroph, and a pure gonadotroph tumor comprising a triple tumor. PitNETs expressing PIT1 and SF1 represent multilineage PitNETs. These rare tumors have variable clinical and morphological features, most often presenting as large tumors with GH excess and occasionally as one of multiple synchronous PitNETs of distinct lineages.

Pituitary Neuroendocrine Tumor: Is It Benign or Malignant?

The World Health Organization (WHO) updated the classification of pituitary tumors in 2022. The new classification presents detailed histological subtyping of a pituitary neuroendocrine tumor (PitNET) based on the tumor cell lineage, cell type, and related characteristics. The immunohistochemistry for pituitary transcription factors (PIT1, TPIT, SF1, GATA3, and ERα) is routinely needed in this classification. The controversy regarding the change of behavior code of all PitNET/pituitary adenoma from "0" for benign tumors to "3" for primary malignant tumors is a topic of debate among experts, nowadays. Some authors represent that pituitary adenoma has a tendency for hemorrhage and necrosis and frequent invasion of the cavernous sinus. However, most small PitNET/pituitary adenoma do not need any treatment because of benign biologic behavior or less than 5% recurrence after gross total removal. Pituitary apoplexy is also benign nature but has a tendency of cranial nerve compression or panhypopituitarism. Most of cavernous invasion is compression of the cavernous sinus. Aggressive PitNET/pituitary adenoma with malignant biological behavior is less than 1%.

New pathological classification and clinical implications of pituitary neuroendocrine tumors of the 2022 WHO version

In 2022, the World Health Organization proposed a new classification for pituitary adenomas. The major nomenclature change from the previous edition was the transition from"adenoma"to"pituitary neuroendocrine tumor"(PitNETs). The new classification provided the detailed histological subtypes of PitNETs for routine use of antibodies such as pituitary transcription factors (PIT1, TPIT, SF1, GATA3, and ERα) and hormones. The major PIT1, TPIT, and SF1 lineage-defined PitNETs types and subtypes featured distinct morphologic, molecular, and clinical differences. Unlike the 2017 WHO classification, the 2022 WHO version updated some concepts as follows: (1) Mammosomatotroph, acidophil stem cell tumors and mixed somatotroph/lactotroph tumor represented distinct PIT1-lineage PitNETs; (2) The diagnostic category of PIT1-positive plurihormonal tumor was replaced by the immature PIT1-lineage tumor and the mature plurihormonal PIT1-lineage tumor; (3) The term"metastatic PitNET"was advocated to replace the previous terminology"pituitary carcinoma". The new classification emphasizes the importance of pathological classification of PitNETs. Obviously, accurate pathological interpretation is the key to judge the clinical treatment pathway and prognosis of patients.

OR08-1 PROP1 Is Not Essential For Pituitary Cells Terminal Differentiation

Abstract Introduction The pituitary gland controls several mechanisms as metabolism, growth, and reproduction, in response to hypothalamic stimuli. The adequate temporal/ spatial expression of transcription factors is mandatory for a normal pituitary development. PROP1 transcription factor is widely known as a key pituitary regulator. Pathogenic variants in the PROP1 gene are the main familial causes of hypopituitarism accounting for about 54% of the cases. Aim To characterize the expression of genes involved in pituitary cells determination and specification during pituitary high demand period such as sexual maturation compared to adulthood in the Ames mice. Methods Weight and naso-anal length were measured. Pituitary glands were collected from 5 wild type (WT) and 5 prop1 mutant (Mut) animals with 30 (P30), 40, (P40), and 60 (P60) days after birth. RT-qPCR was performed to analyze the pituitary transcription factors Sox2, Sox3, Hesx1, Otx2, and genes codifying the hormones GH, TSH, LH/ FSH, CGA, and PRL by SYBR® Green (QIAGEN, Valencia, CA). They were normalized by endogenous genes and performed in triplicate. The target genes relative quantification was performed using the mutant related to its age paired wild type as a calibrator and the results were expressed as fold change. Immunofluorescence of SOX2 (ab97959, Abcam, UK) (1: 1600) and pituitary hormones GH, LH, and FSH (1: 250) were done in pituitaries at P60 and its aged paired control, stained with propidium iodide (1: 1000) for nucleus and the secondary antibody Alexa FluorÒ488 (ab150077, Abcam, UK) (1: 1000). Results All mutant mice presented decreased weight and naso-anal length at the three analyzed periods. The expression of the pituitary stem/ progenitor cell marker Sox2 was increased at P30 and P60 and decreased at P40. Sox3 was increased at P30 and decreased at P40 and P60. Hesx1 was increased at P30 and P60 and decreased at P40. Otx2 was increased at all periods. At P30 the genes codifying pituitary hormones was decreased, except for Tsh and Fsh. At P40 it was observed increased expression of the genes codifying Gh, Lh, Fsh and Prl, while Tsh and Cga expression was reduced. At P60 all pituitary hormones codifying genes presented decreased expression. The immunofluorescence at P60 showed increased expression of SOX2, similar expression of FSH, and decreased expression of GH and LH related to their age paired WT. Conclusion Despite the absence of PROP1, Hesx1 is downregulated at P40. Pituitary cell subtype differentiation and hormonal production is observed at transcriptional and protein levels, showing that pituitary cells can differentiate and produce hormones in the absence of Prop1. The recovery of pituitary capacity to differentiate in mutant suggests the involvement of another factor in the pituitary cell differentiation pathway that could compensate the lack of Prop1. Presentation: Saturday, June 11, 2022 11:30 a.m. - 11:45 a.m.

RF17 | PMON23 Argentinian multicentric genetic study of pituitary hormonal deficiencies using a custom panel based on single molecule molecular inversion probes

Abstract Hypopituitarism with deficiency of one or more pituitary hormones (combined pituitary hormone deficiency or CPHD) can vary in severity and age at presentation. Additionally, the hormone abnormalities may evolve with time necessitating frequent evaluation. These hormonal deficits can also be present as part of a syndrome, with patients showing extrapituitary abnormalities such as eye or forebrain malformations. Over the past decade, there has been an explosion in the knowledge of the genetic cascade that orchestrates hypothalamic and pituitary development. Several transcription factors and signaling molecules are critical for cell differentiation and proliferation at a very early stage of gestation. However, more genes remain to be identified in order to provide patients with a definitive aetiology. We studied 95 children with congenital hypopituitarism from seven pediatric hospitals from Argentina. Children with non-endocrine, non-familial idiopathic short stature served as a control group (n=100). A custom exon capture panel based on single-molecule molecular inversion probes sequencing (MIPS) was performed in probands and parents. This panel tests 104 genes: including a selection of reported and candidate genes chosen from our knowledge of pituitary development in mice and PROP1 interacting proteins. We found at least 1 variant in 50 probands. The prevalence of known variants in the pituitary transcription factor genes PROP1 and PIT1 (frequently mutated in CPHD) was low in our cohort. A significant number of disease-causing variants were found in LHX3, LHX4, GLI2 and OTX2. An important advance of our study is the identification of pathogenic variants in recently discovered and novel genes. We found an heterozygous variant in the Roundabout (ROBO) receptor homolog 1 gene: ROBO1;p.Arg1504* in a patient with CPHD and septo-optic dysplasia (SOD); two variants in Steroid Receptor SRA1: p. Ile179Thr and p.Val110delinsArgLeu in a patient with CPHD and hypogonadism hypogonadotropic and a missense variant in Semaphorin 3A SEMA3A: p.Val588Leu in a case of CPHD and aortic coarctation. Our findings support evidence that the etiology of congenital hypopituitarism is highly heterogeneous and may be infrequently monogenic with full penetrance, underlying a more complex pathogenesis. Presentation: Sunday, June 12, 2022 12:36 p.m. - 12:41 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

CRHR1 mediates the transcriptional expression of pituitary hormones and their receptors under hypoxia.

Hypothalamus-pituitary-adrenal (HPA) axis plays critical roles in stress responses under challenging conditions such as hypoxia, via regulating gene expression and integrating activities of hypothalamus-pituitary-targets cells. However, the transcriptional regulatory mechanisms and signaling pathways of hypoxic stress in the pituitary remain to be defined. Here, we report that hypoxia induced dynamic changes in the transcription factors, hormones, and their receptors in the adult rat pituitary. Hypoxia-inducible factors (HIFs), oxidative phosphorylation, and cAMP signaling pathways were all differentially enriched in genes induced by hypoxic stress. In the pituitary gene network, hypoxia activated c-Fos and HIFs with specific pituitary transcription factors (Prop1), targeting the promoters of hormones and their receptors. HIF and its related signaling pathways can be a promising biomarker during acute or constant hypoxia. Hypoxia stimulated the transcription of marker genes for microglia, chemokines, and cytokine receptors of the inflammatory response. Corticotropin-releasing hormone receptor 1 (CRHR1) mediated the transcription of Pomc, Sstr2, and Hif2a, and regulated the function of HPA axis. Together with HIF, c-Fos initiated and modulated dynamic changes in the transcription of hormones and their receptors. The receptors were also implicated in the regulation of functions of target cells in the pituitary network under hypoxic stress. CRHR1 played an integrative role in the hypothalamus-pituitary-target axes. This study provides new evidence for CRHR1 involved changes of hormones, receptors, signaling molecules and pathways in the pituitary induced by hypoxia.

Thyrotropinoma with silent somatotroph and lactotroph adenoma during pregnancy.

SummaryThyrotropinomas are an uncommon cause of hyperthyroidism and are exceedingly rarely identified during pregnancy, with limited evidence to guide management. Most commonly they present as macroadenomas and may cause symptoms of mass effect including headache, visual field defects and hypopituitarism. We present a case of a 35-year-old woman investigated for headaches in whom a 13 mm thyrotropinoma was found. In the lead-up to planned trans-sphenoidal surgery (TSS), she spontaneously conceived and surgery was deferred, as was pharmacotherapy, at her request. The patient was closely monitored through her pregnancy by a multi-disciplinary team and delivered without complication. Pituitary surgery was performed 6 months post-partum. Isolated secondary hypothyroidism was diagnosed postoperatively and replacement thyroxine was commenced. Histopathology showed a double lesion with predominant pituitary transcription factor-1 positive, steroidogenic factor negative plurihormonal adenoma and co-existent mixed thyroid-stimulating hormone, growth hormone, lactotroph and follicle-stimulating hormone staining with a Ki-67 of 1%. This case demonstrates a conservative approach to thyrotropinoma in pregnancy with a successful outcome. This highlights the need to consider the timing of intervention with careful consideration of risks to mother and fetus.Learning pointsThyrotropinomas are a rare cause of secondary hyperthyroidism. Patients may present with hyperthyroidism or symptoms of mass effect, including headaches or visual disturbance.Thyrotropinoma in pregnancy presents a number of pituitary-related risks including pituitary apoplexy and compression of local structures.Hyperthyroidism in pregnancy raises the risk of complications including spontaneous abortion, preeclampsia, low birthweight and premature labour.Timing of medical and surgical therapies must be carefully considered. A conservative approach requires careful monitoring in case emergent intervention is required.

Clinical significance and potential regulatory mechanism of overexpression of pituitary tumor-transforming gene transcription factor in bladder cancer

BackgroundPituitary tumor transforming gene-1 (PTTG1) transcription factor is identified as carcinogenic and associated with tumor invasiveness, but its role in bladder cancer (BLCA) remains obscure. This research is intended to analyze the aberrant expression and clinical significance of PTTG1 in BLCA, explore the relationship between PTTG1 and tumor microenvironment characteristics and predict its potential transcriptional activity in BLCA tissue.MethodsWe compared the expression discrepancy of PTTG1 mRNA in BLCA and normal bladder tissue, using the BLCA transcriptomic datasets from GEO, ArrayExpress, TCGA, and GTEx. In-house immunohistochemical staining was implemented to determine the PTTG1 protein intensity. The prognostic value of PTTG1 was evaluated using the Kaplan-Meier Plotter. CRISPR screen data was utilized to estimate the effect PTTG1 interference has on BLCA cell lines. We predicted the abundance of the immune cells in the BLCA tumor microenvironment using the microenvironment cell populations-counter and ESTIMATE algorithms. Single-cell RNA sequencing data was applied to identify the major cell types in BLCA, and the dynamics of BLCA progression were revealed using pseudotime analysis. PTTG1 target genes were predicted by CistromeDB.ResultsThe elevated expression level of PTTG1 was confirmed in 1037 BLCA samples compared with 127 non-BLCA samples, with a standardized mean difference value of 1.04. Higher PTTG1 expression status exhibited a poorer BLCA prognosis. Moreover, the PTTG1 Chronos genetic effect scores were negative, indicating that PTTG1 silence may inhibit the proliferation and survival of BLCA cells. With PTTG1 mRNA expression level increasing, higher natural killer, cytotoxic lymphocyte, and monocyte lineage cell infiltration levels were observed. A total of four candidate targets containing CHEK2, OCIAD2, UBE2L3, and ZNF367 were determined ultimately.ConclusionsPTTG1 mRNA over-expression may become a potential biomarker for BLCA prognosis. Additionally, PTTG1 may correlate with the BLCA tumor microenvironment and exert transcriptional activity by targeting CHEK2, OCIAD2, UBE2L3, and ZNF367 in BLCA tissue.

A Clinicopathological and Molecular Analysis of Sellar/Suprasellar Neurocytoma Mimicking Pituitary Adenoma.

ObjectiveTo investigate the clinicopathological characteristics, molecular genetic characteristics and prognosis of extraventricular neurocytoma located in the sellar/suprasellar region.MethodsSeven archived tumor samples derived from 4 patients with neurocytoma in the sellar/suprasellar region were collected from the First Affiliated Hospital of Fujian Medical University and the Affiliated Hospital of Qingdao University and retrospectively analyzed for clinical manifestations, imaging features, and histopathological features. Neuronal and pituitary biomarkers and molecular features were detected in these tumor tissues by immunohistochemistry and FISH or Sanger sequencing. The related literature was reviewed.ResultsThree patients were female, while 1 was male, with an average age of 35.5 years (range: 27 to 45 years). The initial manifestations were mainly headache and blurred vision in both eyes. The first MRI examination showed marginally enhancing masses in the intrasellar or intra- to suprasellar region. The diagnosis of pituitary adenomas was based on imaging features. The levels of pituitary hormones were normal. Histologically, the tumor cells were arranged in a sheet-like, monotonous architecture and were uniform in size and shape with round to oval, exquisite and hyperchromatic nuclei, which densely packed close to one another and were separated only by a delicate neuropil background. There was no evident mitosis, necrosis or microvascular proliferation. The three cases of recurrent tumors were highly cellular and showed increased mitotic activity. Immunohistochemically, the tumor cells were positive for syn, CR, CgA, and vasopressin and were focally positive for NeuN, TTF-1, NF, CK8, vimentin, and S100 proteins. Other markers, including IDH1, BRAF VE1, Olig-2, and EMA, were negative. Pituitary transcription factors and anterior pituitary hormones were negative. Molecular genetic testing showed that the tumor cells lacked IDH gene mutations, LOH of 1p/19q, MYCN amplification, and EGFR alteration. With a median follow-up of 74.5 months (range 23 to 137 months), 3 patients relapsed at 11, 50, and 118 months after the initial surgery.ConclusionThe morphological features and immunophenotypes of neurocytoma in the sellar/suprasellar region are similar to those of classic central neurocytoma. The prognosis is relatively good. Gross-subtotal resection and atypical subtype may be related to tumor recurrence.

A review of multiomics platforms in pituitary adenoma pathogenesis.

Pituitary adenomas (PA), or pituitary neuroendocrine tumors (PitNETs), represent 15% of all central nervous system tumors. Classic description of PitNETs solely by hormonal classification has given way to key transcription factors that play a role in the pathology of PitNETs including steroidogenic factor-1 (SF-1), t-box pituitary transcription factor (TPIT), and pituitary transcription factor 1 (PIT-1). Germline mutations in various familial PitNETs are discussed including those in familial isolated pituitary adenoma (FIPA), multiple endocrine neoplasia (MEN), neurofibromatosis 1 (NF1), and Carney complex. Recent advances in next generation sequencing have improved insight into the pathogenesis of PitNETs. A review of key studies in evaluating the genomic analysis of PitNETs was performed. Chromosomal mutations, whole exome sequencing, microRNA genomics, methylomics and transcriptomics were analyzed. Moreover, the multiomic analysis of various genomic panels has helped to better understand PA classification.