The causes and consequences of pituitary gigantism

Aberrant hormone receptors regulate a wide spectrum of endocrine tumors

Aberrant G-protein coupled receptor (GPCR) expression is highly prevalent in cortisol-secreting primary bilateral macronodular adrenal hyperplasia (PBMAH) and unilateral adenomas. The aberrant expression of diverse GPCRs and their ligands play an important role in the over-function of various endocrine tumours. Examples include aberrant expression of MC2R, 5-HT4R, AVPR1A, LHCGR, and GnRHR in primary aldosteronism; GCGR, LHCGR, and 5-HT4R in phaeochromocytomas and paragangliomas; TRHR, GnRHR, GIPR, and GRP101 in pituitary somatotroph tumours; AVPR2, D2DR, and SSTR5 in pituitary corticotroph tumours; GLP1R, GIPR, and somatostatin receptors in medullary thyroid carcinoma; and SSTRs, GLP1R, and GIPR in other neuroendocrine tumours. The genetic mechanisms causing the ectopic expression of GIPR in cortisol-secreting PBMAHs and unilateral adenomas have been identified, but distinct mechanisms are implicated in other endocrine tumours. Development of functional imaging targeting aberrant GPCRs should be useful for identification and for specific therapies of this wide spectrum of tumours. The aim of this review is to show that the regulation of endocrine tumours by aberrant GPCR is not restricted to cortisol-secreting adrenal lesions, but also occurs in tumours of several other organs.

Diagnosis and management of pituitary adenomas in children and adolescents

BACKGROUND

Pituitary adenomas (PAs)-also now called pituitary neuroendocrine tumours or Pit-NETS-are rare in children and adolescents and exceptional below the age of 10. Most evidence-based high-quality data are derived from larger studies in adult patients.

AIMS

We will review recent knowledge on the epidemiology, clinical features, diagnosis, and treatment modalities of the different types of pituitary adenomas diagnosed in children and adolescents, emphasizing the many reasons why these cases should be discussed within pituitary-specific multidisciplinary teams with experts from both paediatric and adult practice.

CONCLUSIONS

Paediatric PA presents multiple peculiarities that may challenge their adequate management. They are overall proportionally larger and more aggressive than in adults, with potential mass effects including hypopituitarism. Hormonal hypersecretion is frequent, resulting in clinical syndromes affecting normal growth and pubertal development. Prolactinomas represent the most frequent subtype of PA found during childhood, followed by adrenocorticotropin (ACTH) and growth hormone (GH)-secreting adenomas, while clinically non-functioning adenomas are exceptionally diagnosed before the age of 16. The occurrence of a pituitary tumour in a young individual should also prompt genetic testing in each case, searching for either germline mutations in one of the known genes that may drive inherited/familial PA (such as the multiple endocrine neoplasia type 1 or MEN1 gene, or the aryl hydrocarbon receptor interacting protein or AIP gene), or for a mosaic activating mutation of GNAS as found in the McCune-Albright syndrome.

The Genetic Pathophysiology and Clinical Management of the TADopathy, X-Linked Acrogigantism

Pituitary gigantism is a rare manifestation of chronic growth hormone (GH) excess that begins before closure of the growth plates. Nearly half of patients with pituitary gigantism have an identifiable genetic cause. X-linked acrogigantism (X-LAG; 10% of pituitary gigantism) typically begins during infancy and can lead to the tallest individuals described. In the 10 years since its discovery, about 40 patients have been identified. Patients with X-LAG usually develop mixed GH and prolactin macroadenomas with occasional hyperplasia that secrete copious amounts of GH, and frequently prolactin. Circulating GH-releasing hormone is also elevated in a proportion of patients. X-LAG is caused by constitutive or sporadic mosaic duplications at chromosome Xq26.3 that disrupt the normal chromatin architecture of a topologically associating domain (TAD) around the orphan G-protein-coupled receptor, GPR101. This leads to the formation of a neo-TAD in which GPR101 overexpression is driven by ectopic enhancers ("TADopathy"). X-LAG has been seen in 3 families due to transmission of the duplication from affected mothers to sons. GPR101 is a constitutively active receptor with an unknown natural ligand that signals via multiple G proteins and protein kinases A and C to promote GH/prolactin hypersecretion. Treatment of X-LAG is challenging due to the young patient population and resistance to somatostatin analogs; the GH receptor antagonist pegvisomant is often an effective option. GH, insulin-like growth factor 1, and prolactin hypersecretion and physical overgrowth can be controlled before definitive adult gigantism occurs, often at the cost of permanent hypopituitarism.

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 1, general recommendations

Tumours of the anterior part of the pituitary gland represent just 1% of all childhood (aged <15 years) intracranial neoplasms, yet they can confer high morbidity and little evidence and guidance is in place for their management. Between 2014 and 2022, a multidisciplinary expert group systematically developed the first comprehensive clinical practice consensus guideline for children and young people under the age 19 years (hereafter referred to as CYP) presenting with a suspected pituitary adenoma to inform specialist care and improve health outcomes. Through robust literature searches and a Delphi consensus exercise with an international Delphi consensus panel of experts, the available scientific evidence and expert opinions were consolidated into 74 recommendations. Part 1 of this consensus guideline includes 17 pragmatic management recommendations related to clinical care, neuroimaging, visual assessment, histopathology, genetics, pituitary surgery and radiotherapy. While in many aspects the care for CYP is similar to that of adults, key differences exist, particularly in aetiology and presentation. CYP with suspected pituitary adenomas require careful clinical examination, appropriate hormonal work-up, dedicated pituitary imaging and visual assessment. Consideration should be given to the potential for syndromic disease and genetic assessment. Multidisciplinary discussion at both the local and national levels can be key for management. Surgery should be performed in specialist centres. The collection of outcome data on novel modalities of medical treatment, surgical intervention and radiotherapy is essential for optimal future treatment.

A Potent Neutralizing Monoclonal Antibody to Human Growth Hormone Suppresses Insulin-Like Growth Factor-1 in Female Rats

Acromegaly and gigantism are disorders caused by hypersecretion of growth hormone (GH), usually from pituitary adenomas. Although somatostatin analogues (SSA), dopamine agonists, and GH receptor antagonists are important therapeutic agents, all of these have issues with their effectiveness, safety, and/or convenience of use. To overcome these, we developed a GH-specific potent neutralizing a mouse monoclonal antibody (mAb) named 13H02. 13H02 selectively bound both to human and monkey GH with high affinity, and strongly inhibited the biological activity of GH in the Nb2 rat lymphoma cell proliferation assay. In hypophysectomized/GH-supplemented rats, a single subcutaneous administration of 13H02 significantly and dose-dependently lowered the serum insulin-like growth factor-1 levels. To pursue the therapeutic potential of this antibody for acromegaly and gigantism, we humanized 13H02 to reduce its immunogenicity and applied a single amino acid mutation in the Fc region to extend its serum half-life. The resulting antibody, Hu-13H02m, also showed GH-specific neutralizing activity, similar to the parental 13H02, and showed improved binding affinity to human FcRn.

Maternal nanoplastic ingestion induces an increase in offspring body weight through altered lipid species and microbiota

The rapidly increasing prevalence of obesity and overweight, especially in children and adolescents, has become a serious societal issue. Although various genetic and environmental risk factors for pediatric obesity and overweight have been identified, the problem has not been solved. In this study, we examined whether environmental nanoplastic (NP) pollutants can act as environmental obesogens using mouse models exposed to NPs derived from polystyrene and polypropylene, which are abundant in the environment. We found abnormal weight gain in the progeny until 6 weeks of age following the oral administration of NPs to the mother during gestation and lactation. Through a series of experiments involving multi-omic analyses, we have demonstrated that NP-induced weight gain is caused by alterations in the lipid composition (lysophosphatidylcholine/phosphatidylcholine ratio) of maternal breast milk and he gut microbiota distribution of the progeny. These data indicate that environmental NPs can act as obesogens in childhood.

Basal interaction of the orphan receptor GPR101 with arrestins leads to constitutive internalization

GPR101 is an orphan G protein-coupled receptor that promotes growth hormone secretion in the pituitary. The microduplication of the GPR101 gene has been linked with the X-linked acrogigantism, or X-LAG, syndrome. This disease is characterized by excessive growth hormone secretion and abnormal rapid growth beginning early in life. Mechanistically, GPR101 induces growth hormone secretion through constitutive activation of multiple heterotrimeric G proteins. However, the full scope of GPR101 signaling remains largely elusive. Herein, we investigated the association of GPR101 to multiple transducers and uncovered an important basal interaction with Arrestin 2 (β-arrestin 1) and Arrestin 3 (β-arrestin 2). By using a GPR101 mutant lacking the C-terminus and cell lines with an Arrestin 2/3 null background, we show that the arrestin association leads to constitutive clathrin- and dynamin-mediated GPR101 internalization. To further highlight GPR101 intracellular fate, we assessed the colocalization of GPR101 with Rab protein markers. Internalized GPR101 was mainly colocalized with the early endosome markers, Rab5 and EEA-1, and to a lesser degree with the late endosome marker Rab7. However, GPR101 was not colocalized with the recycling endosome marker Rab11. These findings show that the basal arrestin recruitment by GPR101 C-terminal tail drives the receptor constitutive clathrin-mediated internalization. Intracellularly, GPR101 concentrates in the endosomal compartment and is degraded through the lysosomal pathway. In conclusion, we uncovered a constitutive intracellular trafficking of GPR101 that potentially represents an important layer of regulation of its signaling and function.

Growth Hormone Treatment for Non-GHD Disorders: Excitement Tempered by Biology

The success of growth hormone (GH) replacement in children with classical GH deficiency has led to excitement that other causes of short stature may benefit similarly. However, clinical experience has shown less consistent and generally less dramatic effects on adult height, perhaps not surprising in light of increased understanding of GH and growth plate biology. Nonetheless, clinical demand for GH treatment continues to grow. Upon the 20th anniversary of the US Food and Drug Administration's approval of GH treatment for idiopathic short stature, this review will consider the factors underlying the expansion of GH treatment, the biological mechanisms of GH action, the non-GH-deficient uses of GH as a height-promoting agent, biological constraints to GH action, and future directions.

Epigenetic Causes of Overgrowth Syndromes

Human overgrowth disorders are characterized by excessive prenatal and/or postnatal growth of various tissues. These disorders often present with tall stature, macrocephaly, and/or abdominal organomegaly and are sometimes associated with additional phenotypic abnormalities such as intellectual disability and increased cancer risk. As the genetic etiology of these disorders have been elucidated, a surprising pattern has emerged. Multiple monogenic overgrowth syndromes result from variants in epigenetic regulators: variants in histone methyltransferases NSD1 and EZH2 cause Sotos syndrome and Weaver syndrome, respectively, variants in DNA methyltransferase DNMT3A cause Tatton-Brown-Rahman syndrome, and variants in chromatin remodeler CHD8 cause an autism spectrum disorder with overgrowth. In addition, very recently, a variant in histone reader protein SPIN4 was identified in a new X-linked overgrowth disorder. In this review, we discuss the genetics of these overgrowth disorders and explore possible common underlying mechanisms by which epigenetic pathways regulate human body size.

Position statement on the diagnosis and management of acromegaly: The French National Diagnosis and Treatment Protocol (NDTP)

Acromegaly is a rare disease with prevalence of approximately 60 cases per million, slight female predominance and peak onset in adults in the fourth decade. Clinical diagnosis is often delayed by several years due to the slowly progressive onset of symptoms. There are multiple clinical criteria that define acromegaly: dysmorphic syndrome of insidious onset, symptoms related to the pituitary tumor (headaches, visual disorders), general signs (sweating, carpal tunnel syndrome, joint pain, etc.), complications of the disease (musculoskeletal, cardiovascular, pneumological, dental, metabolic comorbidities, thyroid nodules, colonic polyps, etc.) or sometimes clinical signs of associated prolactin hypersecretion (erectile dysfunction in men or cycle disorder in women) or concomitant mass-induced hypopituitarism (fatigue and other symptoms related to pituitary hormone deficiencies). Biological confirmation is based initially on elevated IGF-I and lack of GH suppression on oral glucose tolerance test or an elevated mean GH on repeated measurements. In confirmed cases, imaging by pituitary MRI identifies the causal tumor, to best determine management. In a minority of cases, acromegaly can be linked to a genetic predisposition, especially when it occurs at a young age or in a familial context. The first-line treatment is most often surgical removal of the somatotroph pituitary tumor, either immediately or after transient medical treatment. Medical treatments are most often proposed in patients not controlled by surgical removal. Conformal or stereotactic radiotherapy may be discussed on a case-by-case basis, especially in case of drug inefficacy or poor tolerance. Acromegaly should be managed by a multidisciplinary team, preferably within an expert center such as a reference or skill center for rare pituitary diseases.

Genetics of Diffuse Idiopathic Skeletal Hyperostosis and Ossification of the Spinal Ligaments

PURPOSE OF REVIEW

The study aims to provide updated information on the genetic factors associated with the diagnoses 'Diffuse Idiopathic Skeletal Hyperostosis' (DISH), 'Ossification of the Posterior Longitudinal Ligament' (OPLL), and in patients with spinal ligament ossification.

RECENT FINDINGS

Recent studies have advanced our knowledge of genetic factors associated with DISH, OPLL, and other spinal ossification (ossification of the anterior longitudinal ligament [OALL] and the yellow ligament [OYL]). Several case studies of individuals afflicted with monogenic disorders, such as X-linked hypophosphatemia (XLH), demonstrate the strong association of fibroblast growth factor 23-related hypophosphatemia with OPLL, suggesting that pathogenic variants in PHEX, ENPP1, and DMP1 are associated with FGF23-phosphate wasting phenotype and strong genetic factors placing patients at risk for OPLL. Moreover, emerging evidence demonstrates that heterozygous and compound heterozygous ENPP1 pathogenic variants inducing 'Autosomal Recessive Hypophosphatemic Rickets Type 2' (ARHR2) also place patients at risk for DISH and OPLL, possibly due to the loss of inhibitory plasma pyrophosphate (PPi) which suppresses ectopic calcification and enthesis mineralization. Our findings emphasize the importance of genetic and plasma biomarker screening in the clinical evaluation of DISH and OPLL patients, with plasma PPi constituting an important new biomarker for the identification of DISH and OPLL patients whose disease course may be responsive to ENPP1 enzyme therapy, now in clinical trials for rare calcification disorders.

Pediatric growth hormone and prolactin-secreting tumor associated with an AIP mutation and a MEN1 variant of uncertain significance

OBJECTIVES

Pituitary gigantism is a rare condition and it often has an identifiable genetic cause. In this article we report a case of a young girl with pituitary gigantism and two genetic changes.

CASE PRESENTATION

A 15-year-old girl with primary amenorrhea was diagnosed with a growth hormone (GH) and prolactin (PRL)-producing tumor, needing surgery and medical treatment with octreotide in order to achieve disease control. The co-occurrence of an AIP mutation and a MEN1 variant of uncertain significance was demonstrated in this patient. The germline mutation involving AIP was inherited from her father who at the age of 55 was unaffected and the MEN1 variant was a de novo duplication of the region 11q13.1. The latter variant, not previously reported, is unlikely to be pathogenic. Nonetheless, screening for other components of multiple endocrine neoplasia type 1 (MEN1) was performed and proved negative.

CONCLUSIONS

The rare co-occurrence of an AIP mutation and a MEN 1 variant of uncertain significance was demonstrated in this patient.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

Hormone supply to the pituitary gland: A comprehensive investigation of female‑related tumors (Review)

The hypothalamus acts on the pituitary gland after signal integration, thus regulating various physiological functions of the body. The pituitary gland includes the adenohypophysis and neurohypophysis, which differ in structure and function. The hypothalamus-hypophysis axis controls the secretion of adenohypophyseal hormones through the pituitary portal vein system. Thyroid-stimulating hormone, adrenocorticotropic hormone, gonadotropin, growth hormone (GH), and prolactin (PRL) are secreted by the adenohypophysis and regulate the functions of the body in physiological and pathological conditions. The aim of this review was to summarize the functions of female-associated hormones (GH, PRL, luteinizing hormone, and follicle-stimulating hormone) in tumors. Their pathophysiology was described and the mechanisms underlying female hormone-related diseases were investigated.

Duplications disrupt chromatin architecture and rewire GPR101-enhancer communication in X-linked acrogigantism

X-linked acrogigantism (X-LAG) is the most severe form of pituitary gigantism and is characterized by aggressive growth hormone (GH)-secreting pituitary tumors that occur in early childhood. X-LAG is associated with chromosome Xq26.3 duplications (the X-LAG locus typically includes VGLL1, CD40LG, ARHGEF6, RBMX, and GPR101) that lead to massive pituitary tumoral expression of GPR101, a novel regulator of GH secretion. The mechanism by which the duplications lead to marked pituitary misexpression of GPR101 alone was previously unclear. Using Hi-C and 4C-seq, we characterized the normal chromatin structure at the X-LAG locus. We showed that GPR101 is located within a topologically associating domain (TAD) delineated by a tissue-invariant border that separates it from centromeric genes and regulatory sequences. Next, using 4C-seq with GPR101, RBMX, and VGLL1 viewpoints, we showed that the duplications in multiple X-LAG-affected individuals led to ectopic interactions that crossed the invariant TAD border, indicating the existence of a similar and consistent mechanism of neo-TAD formation in X-LAG. We then identified several pituitary active cis-regulatory elements (CREs) within the neo-TAD and demonstrated in vitro that one of them significantly enhanced reporter gene expression. At the same time, we showed that the GPR101 promoter permits the incorporation of new regulatory information. Our results indicate that X-LAG is a TADopathy of the endocrine system in which Xq26.3 duplications disrupt the local chromatin architecture forming a neo-TAD. Rewiring GPR101-enhancer interaction within the new regulatory unit is likely to cause the high levels of aberrant expression of GPR101 in pituitary tumors caused by X-LAG.

The true story of the "strong and gentle" Acciano's Giant

This is the story of a giant who lived in Abruzzo 200 years ago. He became a symbol for his people and a strong resilience generator. Gigantism, in the history of humanity has always attracted attention, albeit passing over the centuries from myth, from divinity to the freak phenomenon, the freak of nature that becomes a spectacle to show off. The attraction for understanding the pathophysiological mechanisms underlying gigantism developed by the end of 19th century. Increased levels of growth hormone (GH) or insulin-like growth hormone 1 (IGF1) causes overgrowth in pituitary gigantism. The imposing size of the body, in our imagination, represents strength and health, reason why in our imagination it almost becomes a divine mythical image. The story of the Acciano's Giant represents a cultural heritage that passes from one generation to the next, that contributes in giving a sense of identity and continuity. It provides a link from past to present and to the future. Encourages a sense of identity and responsibility contributing to social cohesion, helping individuals to feel members of one community. A disease, represented by the Giant, has become a symbol capable of bringing the community together and giving it the strength to react to environment, nature and history. This is a lesson that teaches us the sense of community.

Oral Manifestations and Maxillo-Facial Features in the Acromegalic Patient: A Literature Review

Background: Acromegaly is a chronic disease caused by an abnormal secretion of growth hormone (GH) by a pituitary adenoma, resulting in an increased circulating concentration of insulin-like growth factor 1 (IGF-1). The main characteristics are a slow progression of signs and symptoms, with multisystemic involvement, leading to acral overgrowth, progressive somatic changes, and a complex range of comorbidities. Most of these comorbidities can be controlled with treatment. The literature reveals that the most evident and early signs are those related to soft tissue thickening and skeletal growth, especially in the head and neck region. Methods: The authors reviewed the available literature on the clinical oro-dental features of acromegaly, selecting articles from PubMed and Google Scholar. The aim of this review was to summarize all the reported clinical oro-dental features of acromegalic patients. Results: The most common facial dimorphisms involved the maxillo-facial district, with hypertrophy of the paranasal sinuses, thickening of the frontal bones, and protruding glabella, which may be associated with joint pain and clicks. Regarding the oro-dental signs, the most frequent are dental diastema (40–43%), mandibular overgrowth (22–24%), mandibular prognathism (20–22%), and macroglossia (54–58%). These signs of acromegaly can be significantly reduced with adequate treatment, which is more effective when initiated early. Conclusions: Increased awareness of acromegaly among dentists and maxillo-facial surgeons, along with the early identification of oro-facial changes, could lead to an earlier diagnosis and treatment, thereby improving patients’ quality of life and prognosis.

The role of the dentist and orthodontist in recognizing oro-facial manifestations of acromegaly: a questionnaire-based study

PURPOSE

Oro-facial manifestations of acromegaly are among the earliest signs of the disease and are reported by a significant number of patients at diagnosis. Despite this high prevalence of acromegaly oral manifestation, dentists do not play a pivotal role in acromegaly identification and diagnosis. The aim of our study was to evaluate the ability of dentists and orthodontists in the early recognition of the oro-facial manifestations of acromegaly.

METHODS

A telematic questionnaire was administered to dentists and orthodontists. The questionnaire included photos with facial and oral-dental details and lateral teleradiography of acromegaly patients (ACRO).

RESULTS

The study included 426 participants: 220 dentists and 206 orthodontists. Upon reviewing the photos, dentists most often observed mandibular prognathism and lips projection, while orthodontists also reported the impairment of relative soft tissue. Orthodontists, who usually use photos to document patients' oral-facial characteristics, paid more attention to oral-facial impairment than dentists. During dental assessment, 90% of the participants usually evaluated tongue size and appearance, diastemas presence, and signs of sleep impairment (mainly orthodontists). Orthodontists were also more able to identify sella turcica enlargement at teleradiography. A total of 10.8% of the participants had ACRO as patients and 11.3% referred at least one patient for acromegaly suspicion.

CONCLUSION

The study highlighted dentists' strategic role in identifying ACRO. Increasing dentists' awareness about acromegaly clinical issues may improve early diagnosis, potentially resulting in an increased quality of life and decreased mortality among ACRO.

The Internal Cranial Anatomy of a Female With Endocrine Disorders From a Mediaeval Population

Gigantism and acromegaly have been observed in past populations; however, analyses usually focus on the morphological features of the post-cranial skeleton. The aim of this study is to characterize the internal anatomical features of the skull (brain endocast anatomy and asymmetry, frontal pneumatization, cranial thickness, sella turcica size) of an adult individual from the 11-14th centuries with these two diseases, in comparison with non-pathological individuals from the same population. The material consisted of 33 adult skulls from a mediaeval population, one of them belonging to an adult female with endocrine disorders (OL-23/77). Based on the CT scans, the internal cranial anatomy was analysed. The sella turcica of OL-23/77 is much larger than in the comparative sample. The endocast of the individual OL-23/77 shows a left frontal/left occipital petalia, while the comparative population mostly had right frontal/left occipital petalias. The asymmetry in petalia location in OL-23/77 comes within the range of variation observed in the comparative population. The individual has high values for cranial thickness. The frontal sinuses of the specimen analysed are similar in size and shape to the comparative sample only for data scaled to the skull length. Enlarged sella turcica is typical for individuals with acromegaly/gigantism. The pattern of the left frontal/left occipital petalia in the specimen OL-23/77 is quite rare. The position of the endocranial petalias has not influenced the degree of asymmetry in the specimen. Despite the large bone thickness values, skull of OL-23/77 does not show any abnormal features. The skull/endocast relationship in this individual shows some peculiarities in relation to its large size, while other internal anatomical features are within the normal range of variation of the comparative sample.

Neuropathology of Pituitary Adenomas and Sellar Lesions

The pituitary gland is the site of numerous neoplastic and inflammatory processes. The overwhelmingly most frequent tumors arise from cells of the anterior lobe, the pituitary neuroendocrine tumors (PitNETs). Immunohistochemistry assay staining for pituitary hormones is the core tool for classifying PitNETs, resulting in the diagnosis of somatotroph PitNETs, lactotroph PitNETs, and so on. For cases showing no hormonal expression, the updated WHO classification system now considers the assessment of several transcription factors: PIT-1 (pituitary-specific POU-class homeodomain transcription factor); T-PIT (T-box family member TBX19); and SF-1 (steroidogenic factor regulating gonadotroph cell differentiation) before rendering a diagnosis of null cell adenoma. Other tumors and disease processes of this site often mimic PitNETs radiographically and sometimes even clinically (ie, compression of the optic chiasm). These potpourri of processes include germ cell neoplasms (especially germinomas), tumors that originate from Rathke's pouch (craniopharyngiomas, Rathke's cleft cyst), tumors that originate from the posterior lobe of the pituitary (pituicytoma, spindle cell oncocytoma, granular cell tumor), and tumors that originate from the meninges (especially meningiomas). In addition to neoplasms, several described inflammatory and related conditions exist that need to be distinguished from PitNETs. These include lymphocytic hypophysitis and Langerhans cell histiocytosis, a neoplastic disorder of histiocytes. In this review, we aim to briefly describe the main pituitary and sellar lesions, with emphasis on the most common tumors, the PitNETs.

Localized Delivery of Theranostic Nanoparticles and High-Energy Photons using Microneedles-on-Bioelectronics

The low delivery efficiency of light-responsive theranostic nanoparticles (NPs) to target tumor sites, particularly to brain tumors due to the blood-brain barrier, has been a critical issue in NP-based cancer treatments. Furthermore, high-energy photons that can effectively activate theranostic NPs are hardly delivered to the target region due to the strong scattering of such photons while penetrating surrounding tissues. Here, a localized delivery method of theranostic NPs and high-energy photons to the target tumor using microneedles-on-bioelectronics is presented. Two types of microneedles and flexible bioelectronics are integrated and mounted on the edge of surgical forceps. Bioresorbable microneedles containing theranostic NPs deliver the NPs into target tumors (e.g., glioblastoma, pituitary adenoma). Magnetic resonance imaging can locate the NPs. Then, light-guiding/spreading microneedles deliver high-energy photons from bioelectronics to the NPs. The high-energy photons activate the NPs to treat tumor tissues by photodynamic therapy and chemotherapy. The controlled thermal actuation by the bioelectronics accelerates the diffusion of chemo-drugs. The proposed method is demonstrated with mouse tumor models in vivo.

Genetics, clinical features and outcomes of non-syndromic pituitary gigantism: experience of a single center from Sao Paulo, Brazil

PURPOSE

Non-syndromic pituitary gigantism (PG) is a very rare disease. Aryl hydrocarbon receptor-interacting protein (AIP) and G protein-coupled receptor 101 (GPR101) genetic abnormalities represent important etiologic causes of PG and may account for up to 40% of these cases. Here, we aimed to characterize the clinical and molecular findings and long-term outcomes in 18 patients (15 males, three females) with PG followed at a single tertiary center in Sao Paulo, Brazil.

METHODS

Genetic testing for AIP and GPR101 were performed by DNA sequencing, droplet digital PCR and array comparative genomic hybridization (aCGH).

RESULTS

Pathogenic variants in the AIP gene were detected in 25% of patients, including a novel variant in splicing regulatory sequences which was present in a sporadic male case. X-LAG due to GPR101 microduplication was diagnosed in two female patients (12.5%). Of interest, these patients had symptoms onset by age 5 and 9 years old and diagnosis at 5 and 15 years, respectively. X-LAG, but not AIP, patients had a significantly lower age of symptoms onset and diagnosis and a higher height Z-score when compared to non-X-LAG. No other differences in clinical features and/or treatment outcomes were observed among PG based on their genetic background.

CONCLUSION

We characterize the clinical and molecular findings and long-term outcome of the largest single-center PG cohort described so far.

GWAS reveal a role for the central nervous system in regulating weight and weight change in response to exercise

Body size and weight show considerable variation both within and between species. This variation is controlled in part by genetics, but also strongly influenced by environmental factors including diet and the level of activity experienced by the individual. Due to the increasing obesity epidemic in much of the world, there is considerable interest in the genetic factors that control body weight and how weight changes in response to exercise treatments. Here, we address this question in the Drosophila model system, utilizing 38 strains of the Drosophila Genetics Reference Panel. We use GWAS to identify the molecular pathways that control weight and weight changes in response to exercise. We find that there is a complex set of molecular pathways controlling weight, with many genes linked to the central nervous system (CNS). The CNS also plays a role in the weight change with exercise, in particular, signaling from the CNS. Additional analyses revealed that weight in Drosophila is driven by two factors, animal size, and body composition, as the amount of fat mass versus lean mass impacts the density. Thus, while the CNS appears to be important for weight and exercise-induced weight change, signaling pathways are particularly important for determining how exercise impacts weight.

Human growth hormone proteoform pattern changes in pituitary adenomas: Potential biomarkers for 3P medical approaches

Relevance

Human growth hormone (hGH) is synthesized, stored, and secreted by somatotroph cells in the pituitary gland, and promotes human growth and metabolism. Compared to a normal pituitary, a GH-secreting pituitary adenoma can secrete excessive GH to cause pathological changes in body tissues. GH proteoform changes would be associated with GH-related disease pathogenesis.

Purpose

This study aimed to elucidate changes in GH proteoforms between GH-secreting pituitary adenomas and control pituitaries for the predictive diagnostics, targeted prevention, and personalization of medical services.

Methods

The isoelectric point (pI) and relative molecular mass (Mr) are two basic features of a proteoform that can be used to effectively array and detect proteoforms with two-dimensional gel electrophoresis (2DGE) and 2DGE-based western blot. GH proteoforms were characterized with liquid chromatography (LC) and mass spectrometry (MS). Phosphoproteomics, ubiquitinomics, acetylomics, and bioinformatics were used to analyze post-translational modifications (PTMs) of GH proteoforms in GH-secreting pituitary adenoma tissues and control pituitaries.

Results

Sixty-six 2D gel spots were found to contain hGH, including 46 spots (46 GH proteoforms) in GH-secreting pituitary adenomas and 35 spots (35 GH proteoforms) in control pituitaries. Further, 35 GH proteoforms in control pituitary tissues were matched with 35 of 46 GH proteoforms in GH-secreting pituitary adenoma tissues; and 11 GH proteoforms were presented in only GH-secreting pituitary adenoma tissues but not in control pituitary tissues. The matched 35 GH proteoforms showed quantitative changes in GH-secreting pituitary adenomas compared to the controls. The quantitative levels of those 46 GH proteoforms in GH-secreting pituitary adenomas were significantly different from those 35 GH proteoforms in control pituitaries. Meanwhile, different types of PTMs were identified among those GH proteoforms. Phosphoproteomics identified phosphorylation at residues Ser77, Ser132, Ser134, Thr174, and Ser176 in hGH. Ubiquitinomics identified ubiquitination at residue Lys96 in hGH. Acetylomics identified acetylation at reside Lys171 in hGH. Deamination was identified at residue Asn178 in hGH.

Conclusion

These findings provide the first hGH proteoform pattern changes in GH-secreting pituitary adenoma tissues compared to control pituitary tissues, and the status of partial PTMs in hGH proteoforms. Those data provide in-depth insights into biological roles of hGH in GH-related diseases, and identify hGH proteoform pattern biomarkers for treatment of a GH-secreting pituitary adenoma in the context of 3P medicine -predictive diagnostics, targeted prevention, and personalization of medical services.

Supplementary information

The online version contains supplementary material available at 10.1007/s13167-021-00232-7.

Loss-of-Function Variants in the Tumor-Suppressor Gene PTPN14 Confer Increased Cancer Risk

The success of genome-wide association studies (GWAS) in identifying common, low-penetrance variant-cancer associations for the past decade is undisputed. However, discovering additional high-penetrance cancer mutations in unknown cancer predisposing genes requires detection of variant-cancer association of ultra-rare coding variants. Consequently, large-scale next-generation sequence data with associated phenotype information are needed. Here, we used genotype data on 166,281 Icelanders, of which, 49,708 were whole-genome sequenced and 408,595 individuals from the UK Biobank, of which, 41,147 were whole-exome sequenced, to test for association between loss-of-function burden in autosomal genes and basal cell carcinoma (BCC), the most common cancer in Caucasians. A total of 25,205 BCC cases and 683,058 controls were tested. Rare germline loss-of-function variants in PTPN14 conferred substantial risks of BCC (OR, 8.0; P = 1.9 × 10^-12), with a quarter of carriers getting BCC before age 70 and over half in their lifetime. Furthermore, common variants at the PTPN14 locus were associated with BCC, suggesting PTPN14 as a new, high-impact BCC predisposition gene. A follow-up investigation of 24 cancers and three benign tumor types showed that PTPN14 loss-of-function variants are associated with high risk of cervical cancer (OR, 12.7, P = 1.6 × 10^-4) and low age at diagnosis. Our findings, using power-increasing methods with high-quality rare variant genotypes, highlight future prospects for new discoveries on carcinogenesis. SIGNIFICANCE: This study identifies the tumor-suppressor gene PTPN14 as a high-impact BCC predisposition gene and indicates that inactivation of PTPN14 by germline sequence variants may also lead to increased risk of cervical cancer.

A Chinese Case of X-Linked Acrogigantism and Systematic Review

INTRODUCTION

This study described a Chinese case of X-linked acrogigantism (X-LAG) and summarized the characteristics and treatment of all reported cases.

METHODS

Clinical materials and biological samples from a 5-year and 2-month-old female due to "growth acceleration for 4 years" were collected. Array comparative genomic hybrid (aCGH) and further verification were performed. All X-LAG cases from the PubMed and Web of Science databases were collected and summarized with available data.

RESULTS

The patient presented accelerating growth since 1 year, and her height reached 134.6 cm (+5.24 standard deviation score [SDS]) when she was 5-year and 2-month old. She also had coarsening facial features, snoring, and acral enlargement. Growth hormone (GH) was not suppressed by the glucose-GH inhibition test, and insulin-like growth factor 1 (IGF-1) and prolactin (PRL) levels were elevated. Pituitary MRI revealed a pituitary enlargement with a maximum diameter of 22.3 mm. Octreotide imaging indicated the presence of a pituitary adenoma. The tumor shrank slightly after 3 courses of somatostatin analog but without clinical or biochemical remissions, of which the GH nadir value was 9.4 ng/mL, and IGF-1 was elevated to 749 ng/mL. Therefore, she underwent transsphenoidal surgery. Immunohistochemistry showed GH-positive and PRL-positive cells in the pituitary adenoma. Xq26.3 microduplication of the patient's germline DNA was identified by aCGH. Of all 35 reported cases, females accounted for 71.43%. There were 93.10% and 53.83% patients with hyperprolactinemia and hyperinsulinemia, respectively. Pathology showed that 75.00% of cases were adenomas. Ninety percent of cases had germline variants. The clinical and biochemical remission rates were 78.26% and 82.61%, respectively. However, the rate of complication occurrence during therapy reached 80%.

CONCLUSION

It is important to recognize the possibility of X-LAG when a child under 2-year old presents overgrowth. Early diagnosis and treatment are of great importance for better treatment efficacy and clinical outcome.

Growth hormone receptor knockout to reduce the size of donor pigs for preclinical xenotransplantation studies

BACKGROUND

Many genetically multi-modified donor lines for xenotransplantation have a background of domestic pigs with rapid body and organ growth. The intrinsic growth potential of porcine xeno-organs may impair their long-term function after orthotopic transplantation in non-human primate models. Since growth hormone is a major stimulator of postnatal growth, we deleted its receptor (GHR-KO) to reduce the size of donor pigs in one step.

METHODS

Heart weight and proteome profile of myocardium were investigated in GHR-KO and control pigs. GHR-KO mutations were introduced using CRISPR/Cas9 in an α1,3-galactosyltransferase (GGTA1)-deficient background expressing the human cluster of differentiation (hCD46) and human thrombomodulin (hTHBD) to generate quadruple-modified (4GM) pigs.

RESULTS

At age 6 months, GHR-KO pigs had a 61% reduced body weight and a 63% reduced heart weight compared with controls. The mean minimal diameter of cardiomyocytes was 28% reduced. A holistic proteome study of myocardium samples from the two groups did not reveal prominent differences. Two 4GM founder sows had low serum insulin-like growth factor 1 (IGF1) levels (24 ± 1 ng/mL) and reached body weights of 70.3 and 73.4 kg at 9 months. Control pigs with IGF1 levels of 228 ± 24 ng/mL reached this weight range three months earlier. The 4GM sows showed normal sexual development and were mated with genetically multi-modified boars. Offspring revealed the expected Mendelian transmission of the genetic modifications and consistent expression of the transgenes.

CONCLUSION

GHR-KO donor pigs can be used at an age beyond the steepest phase of their growth curve, potentially reducing the problem of xeno-organ overgrowth in preclinical studies.

GPR101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of Gs and Gq/11

Growth hormone (GH) is a key modulator of growth and GH over-secretion can lead to gigantism. One form is X-linked acrogigantism (X-LAG), in which infants develop GH-secreting pituitary tumors over-expressing the orphan G-protein coupled receptor, GPR101. The role of GPR101 in GH secretion remains obscure. We studied GPR101 signaling pathways and their effects in HEK293 and rat pituitary GH3 cell lines, human tumors and in transgenic mice with elevated somatotrope Gpr101 expression driven by the rat Ghrhr promoter (Ghrhr^Gpr101). Here, we report that Gpr101 causes elevated GH/prolactin secretion in transgenic Ghrhr^Gpr101 mice but without hyperplasia/tumorigenesis. We show that GPR101 constitutively activates not only G_s, but also G_q/11 and G_12/13, which leads to GH secretion but not proliferation. These signatures of GPR101 signaling, notably PKC activation, are also present in human pituitary tumors with high GPR101 expression. These results underline a role for GPR101 in the regulation of somatotrope axis function.

Multivariable Prediction Model for Biochemical Response to First-Generation Somatostatin Receptor Ligands in Acromegaly

CONTEXT

First-generation somatostatin receptor ligands (fg-SRLs) represent the mainstay of medical therapy for acromegaly, but they provide biochemical control of disease in only a subset of patients. Various pretreatment biomarkers might affect biochemical response to fg-SRLs.

OBJECTIVE

To identify clinical predictors of the biochemical response to fg-SRLs monotherapy defined as biochemical response (insulin-like growth factor (IGF)-1 ≤ 1.3 × ULN (upper limit of normal)), partial response (>20% relative IGF-1 reduction without normalization), and nonresponse (≤20% relative IGF-1 reduction), and IGF-1 reduction.

DESIGN

Retrospective multicenter study.

SETTING

Eight participating European centers.

METHODS

We performed a meta-analysis of participant data from 2 cohorts (Rotterdam and Liège acromegaly survey, 622 out of 3520 patients). Multivariable regression models were used to identify predictors of biochemical response to fg-SRL monotherapy.

RESULTS

Lower IGF-1 concentration at baseline (odds ratio (OR) = 0.82, 95% confidence interval (CI) 0.72-0.95 IGF-1 ULN, P = .0073) and lower bodyweight (OR = 0.99, 95% CI 0.98-0.99 kg, P = .038) were associated with biochemical response. Higher IGF-1 concentration at baseline (OR = 1.40, (1.19-1.65) IGF-1 ULN, P ≤ .0001), the presence of type 2 diabetes (oral medication OR = 2.48, (1.43-4.29), P = .0013; insulin therapy OR = 2.65, (1.02-6.70), P = .045), and higher bodyweight (OR = 1.02, (1.01-1.04) kg, P = .0023) were associated with achieving partial response. Younger patients at diagnosis are more likely to achieve nonresponse (OR = 0.96, (0.94-0.99) year, P = .0070). Baseline IGF-1 and growth hormone concentration at diagnosis were associated with absolute IGF-1 reduction (β = 0.90, standard error (SE) = 0.02, P ≤ .0001 and β  = 0.002, SE = 0.001, P = .014, respectively).

CONCLUSION

Baseline IGF-1 concentration was the best predictor of biochemical response to fg-SRL, followed by bodyweight, while younger patients were more likely to achieve nonresponse.

Clinical and Molecular Update on Genetic Causes of Pituitary Adenomas

Pituitary adenomas are benign tumors with variable functional characteristics that can have a significant impact on patients. The majority arise sporadically, but an inherited genetic susceptibility is increasingly being recognized. Recent advances in genetics have widened the scope of our understanding of pituitary tumorigenesis. The clinical and genetic characteristics of pituitary adenomas that develop in the setting of germline-mosaic and somatic GNAS mutations (McCune-Albright syndrome and sporadic acromegaly), germline MEN1 mutations (multiple endocrine neoplasia type 1), and germline PRKAR1A mutations (Carney complex) have been well described. Non-syndromic familial cases of isolated pituitary tumors can occur as familial isolated pituitary adenomas (FIPA); mutations/deletions of the AIP gene have been found in a minority of these. Genetic alterations in GPR101 have been identified recently as causing X-linked acro-gigantism (X-LAG) leading to very early-onset pediatric gigantism. Associations of pituitary adenomas with other tumors have been described in syndromes like multiple endocrine neoplasia type 4, pheochromocytoma-paraganglioma with pituitary adenoma association (3PAs) syndrome and some of their genetic causes have been elucidated. The genetic etiologies of a significant proportions of sporadic corticotropinomas have recently been identified with the discovery of USP8 and USP48 mutations. The elucidation of genetic and molecular pathophysiology in pituitary adenomas is a key factor for better patient management and effective follow-up.

Large-scale second-hit AIP deletion causing a pediatric growth hormone-secreting pituitary adenoma: Case report and review of literature

Gigantism (early-onset acromegaly) is a rare pediatric disorder caused by a growth hormone (GH)-secreting pituitary adenoma. Approximately 50% patients of gigantism have a germline mutation, most commonly an inactivating mutation in the aryl-hydrocarbon interacting receptor protein (AIP) gene on chromosome 11q13.2. We present an 11-year-old male patient with a GH-secreting pituitary macroadenoma who presented with excessive growth spurts, behavioral changes, and frontal headaches. He was successfully treated with an endoscopic endonasal gross total resection and subsequently demonstrated biochemical cure. Whole-exome sequencing showed a heterozygous germline mutation in the AIP gene suggesting pituitary adenoma predisposition. Analysis of the tumor tissue revealed a large-scale deletion on chromosome 11 overlapping with AIP leading to bi-allelic AIP loss. Coincident germline and somatic AIP mutations were likely causal in formation of a GH-secreting adenoma with an aggressive phenotype. This case exemplifies the need for early diagnosis and curative surgery in the management of AIP-mutated pituitary adenomas.

Overrepresentation of highly functional T regulatory cells in patients with nonfunctioning pituitary adenoma

Nonfunctioning pituitary adenoma is a common intracranial tumor. Though benign in the majority of cases, complications can be excruciating to the affected individual, and recurrences after tumor removal may happen with more aggressive clinical features. T regulatory (Treg) cells are generally considered a tumor-promoting immune cell type in malignant cancers with currently unclear roles in pituitary adenoma patients. Therefore, we investigated the frequency and functional characteristics of Treg cells in nonfunctioning pituitary adenoma patients before and after tumor removal. Compared to healthy controls, untreated patients with nonfunctioning pituitary adenomas presented an overrepresentation of highly functional circulating FOXP3⁺ Treg cells. Specifically, the FOXP3⁺ Treg cells in patients were slightly upregulated in frequency and displayed markedly elevated capacity to co-produce TGF-β and IL-10. TIM-3 is a negative regulator of proinflammatory immune responses and is expressed by highly activated Treg cells. In both healthy controls and pituitary adenoma patients, TIM-3⁺ Treg cells presented significantly higher levels of TGF-β and IL-10 co-producing cells than TIM-3^- Treg cells but compared to healthy controls, patients with nonfunctioning pituitary adenomas showed significantly higher levels of TIM-3⁺ FOXP3⁺ Treg cells. Interestingly, surgical removal of the tumor significantly reduced the extent of Treg upregulation in patients. Also, resected pituitary adenomas contained highly functional FOXP3⁺ Treg cells, with high levels of TIM-3 expression and high frequency of TGF-β and IL-10 co-producers in the TIM-3⁺ fraction. Overall, these results demonstrate that patients with nonfunctioning pituitary adenomas are characterized by an overrepresentation of highly functional Treg cells.

A standardised diagnostic approach to pituitary neuroendocrine tumours (PitNETs): a European Pituitary Pathology Group (EPPG) proposal

The 2017 World Health Organization (WHO) classification proposes to type and subtype primary adenohypophyseal tumours according to their cell lineages with the aim to establish more uniform tumour groups. The definition of atypical adenoma was removed in favour of high-risk adenoma, and the assessment of proliferative activity and invasion was recommended to diagnose aggressive tumours. Recently, the International Pituitary Pathology Club proposed to replace adenoma with the term of pituitary neuroendocrine tumour (PitNET) to better reflect the similarities between adenohypophyseal and neuroendocrine tumours of other organs. The European Pituitary Pathology Group (EPPG) endorses this terminology and develops practical recommendations for standardised reports of PitNETs that are addressed to histo- and neuropathologists. This brief report presents the results of EPPG's consensus for the reporting of PitNETs and proposes a diagnostic algorithm.

Regulation of growth hormone biosynthesis by Cdk5 regulatory subunit associated protein 1-like 1 (CDKAL1) in pituitary adenomas

CDK5 regulatory subunit associated protein 1-like 1 (CDKAL1) is a tRNA-modifying enzyme that catalyzes 2-methylthiolation (ms²) and has been implicated in the development of type 2 diabetes (T2D). CDKAL1-mediated ms² is important for efficient protein translation and regulates insulin biosynthesis in pancreatic cells. Interestingly, an association between T2D and release of growth hormone (GH) has been reported in humans. However, it is unknown whether CDKAL1 is important for hormone production in the pituitary gland. The present study investigated the role of CDKAL1 in GH-producing pituitary adenomas (GHPAs). CDKAL1 activity was suppressed in GHPAs, as evidenced by a decrease in ms², compared with non-functioning pituitary adenomas (NFPAs), which do not produce specific hormones. Downregulation of Cdkal1 using small interfering and short hairpin RNAs increased the biosynthesis and secretion of GH in rat GH3 cells. Depletion of Cdkal1 increased the cytosolic calcium level via downregulation of DnaJ heat shock protein family (Hsp40) member C10 (Dnajc10), which is an endoplasmic reticulum protein related to calcium homeostasis. This stimulated transcription of GH via upregulation of Pit-1. Moreover, CDKAL1 activity was highly sensitive to proteostatic stress and was upregulated by suppression of this stress. Taken together, these results suggest that dysregulation of CDKAL1 is involved in the pathogenesis of GHPAs, and that modulation of the proteostatic stress response might control CDKAL1 activity and facilitate treatment of GHPAs.

AIP-mutated acromegaly resistant to first-generation somatostatin analogs: long-term control with pasireotide LAR in two patients

Acromegaly is a rare disease due to chronic excess growth hormone (GH) and IGF-1. Aryl hydrocarbon receptor interacting protein (AIP) mutations are associated with an aggressive, inheritable form of acromegaly that responds poorly to SST2-specific somatostatin analogs (SSA). The role of pasireotide, an SSA with affinity for multiple SSTs, in patients with AIP mutations has not been reported. We studied two AIP mutation positive acromegaly patients with early-onset, invasive macroadenomas and inoperable residues after neurosurgery. Patient 1 came from a FIPA kindred and had uncontrolled GH/IGF-1 throughout 10 years of octreotide/lanreotide treatment. When switched to pasireotide LAR, he rapidly experienced hormonal control which was associated with marked regression of his tumor residue. Pasireotide LAR was stopped after >10 years due to low IGF-1 and he maintained hormonal control without tumor regrowth for >18 months off pasireotide LAR. Patient 2 had a pituitary adenoma diagnosed when aged 17 that was not cured by surgery. Chronic pasireotide LAR therapy produced hormonal control and marked tumor shrinkage but control was lost when switched to octreotide. Tumor immunohistochemistry showed absent AIP and SST2 staining and positive SST5. Her AIP mutation positive sister developed a 2.5 cm follicular thyroid carcinoma aged 21 with tumoral loss of heterozygosity at the AIP locus and absent AIP staining. Patients 1 and 2 required multi-modal therapy to control diabetes. On stopping pasireotide LAR after >10 years of treatment, Patient 1's glucose metabolism returned to baseline levels. Long-term pasireotide LAR therapy can be beneficial in some AIP mutation positive acromegaly patients that are resistant to first-generation SSA.

AIP and MEN1 mutations and AIP immunohistochemistry in pituitary adenomas in a tertiary referral center

BACKGROUND

Pituitary adenomas have a high disease burden due to tumor growth/invasion and disordered hormonal secretion. Germline mutations in genes such as MEN1 and AIP are associated with early onset of aggressive pituitary adenomas that can be resistant to medical therapy.

AIMS

We performed a retrospective screening study using published risk criteria to assess the frequency of AIP and MEN1 mutations in pituitary adenoma patients in a tertiary referral center.

METHODS

Pituitary adenoma patients with pediatric/adolescent onset, macroadenomas occurring ≤30 years of age, familial isolated pituitary adenoma (FIPA) kindreds and acromegaly or prolactinoma cases that were uncontrolled by medical therapy were studied genetically. We also assessed whether immunohistochemical staining for AIP (AIP-IHC) in somatotropinomas was associated with somatostatin analogs (SSA) response.

RESULTS

Fifty-five patients met the study criteria and underwent genetic screening for AIP/MEN1 mutations. No mutations were identified and large deletions/duplications were ruled out using MLPA. In a cohort of sporadic somatotropinomas, low AIP-IHC tumors were significantly larger (P = 0.002) and were more frequently sparsely granulated (P = 0.046) than high AIP-IHC tumors. No significant relationship between AIP-IHC and SSA responses was seen.

CONCLUSIONS

Germline mutations in AIP/MEN1 in pituitary adenoma patients are rare and the use of general risk criteria did not identify cases in a large tertiary-referral setting. In acromegaly, low AIP-IHC was related to larger tumor size and more frequent sparsely granulated subtype but no relationship with SSA responsiveness was seen. The genetics of pituitary adenomas remains largely unexplained and AIP screening criteria could be significantly refined to focus on large, aggressive tumors in young patients.

Genetics of Growth Disorders-Which Patients Require Genetic Testing?

The second 360° European Meeting on Growth Hormone Disorders, held in Barcelona, Spain, in June 2017, included a session entitled Pragmatism vs. Curiosity in Genetic Diagnosis of Growth Disorders, which examined current concepts of genetics and growth in the clinical setting, in terms of both growth failure and overgrowth. For patients with short stature, multiple genes have been identified that result in GH deficiency, which may be isolated or associated with additional pituitary hormone deficiencies, or in growth hormone resistance, primary insulin-like growth factor (IGF) acid-labile subunit deficiency, IGF-I deficiency, IGF-II deficiency, IGF-I resistance, and primary PAPP-A2 deficiency. While genetic causes of short stature were previously thought to primarily be associated with the GH-IGF-I axis, it is now established that multiple genetic anomalies not associated with the GH-IGF-I axis can result in short stature. A number of genetic anomalies have also been shown to be associated with overgrowth, some of which involve the GH-IGF-I axis. In patients with overgrowth in combination with an intellectual disability, two predominant gene families, the epigenetic regulator genes, and PI3K/AKT pathway genes, have now been identified. Specific processes should be followed for decisions on which patients require genetic testing and which genes should be examined for anomalies. The decision to carry out genetic testing should be directed by the clinical process, not merely for research purposes. The intention of genetic testing should be to direct the clinical options for management of the growth disorder.