Growth Hormone's Links to Cancer

Management of hypopituitarism: a perspective from the Brazilian Society of Endocrinology and Metabolism

Hypopituitarism is a disorder characterized by insufficient secretion of one or more pituitary hormones. New etiologies of hypopituitarism have been recently described, including head trauma, cerebral hemorrhage, and drug-induced hypophysitis. The investigation of patients with these new disorders, in addition to advances in diagnosis and treatment of hypopituitarism, has increased the prevalence of this condition. Pituitary hormone deficiencies can induce significant clinical changes with consequent increased morbidity and mortality rates, while hormone replacement based on current guidelines protects these patients. In this review, we will first discuss the different etiologies of hypopituitarism and then address one by one the clinical aspects, diagnostic evaluation, and therapeutic options for deficiencies of TSH, ACTH, gonadotropin, and GH. Finally, we will detail the hormonal interactions that occur during replacement of pituitary hormones.

Prevalence of thyroid cancer in patients with acromegaly and non-growth hormone secreting pituitary adenomas: A prospective cross-sectional study

OBJECTIVE

To evaluate the prevalence of differentiated thyroid cancer (DTC) in patients with non-GH secreting pituitary adenomas [NGHPA group: non-functioning (NFPA), prolactin (PRL) and corticotropin (ACTH)-secreting adenomas] compared to patients with acromegaly, a pituitary disease that has been associated with increased risk for thyroid cancer.

PATIENTS AND METHODS

Prospective, cross-sectional study involving consecutive outpatients followed in our institution with diagnosis of acromegaly (n = 71; 43 women, median age 57 yrs) and NGHPA (n = 57; 38 women, median age 48 yrs.; PRL (n = 35), ACTH (n = 7), NFPA (n = 15). All participants were subjected to thyroid ultrasound (US) by the same examiner, and US-guided fine needle aspiration (FNA) biopsy when indicated.

RESULTS

Thyroid volume was higher in acromegaly than in NGHPA (median 12.5 ml vs 6.3 ml; p < 0.0001), and thyroid nodules were present in 27/71 (38.0%) of acromegaly patients and in 14/57 (24.6%) of NGHPA group. FNA was indicated in 15/27 (55.5%) of acromegaly patients [Bethesda I (n = 1); II (n = 11), III (n = 1), two patients refused FNA], and in 8/14 (57.1%) of the NGHPA group [Bethesda I (n = 2); II (n = 4); V (n = 1); VI (n = 1)]. The two patients of NGHPA group with Bethesda V and VI were operated and papillary carcinoma was confirmed histologically.

CONCLUSION

DTC was not detected in our acromegaly patients and its presence in patients with NGHPA suggests that DTC predisposition is not related to GH excess.

Increased risk of preneoplastic colonic lesions and colorectal carcinoma in acromegaly: multicenter case-control study

PURPOSE

Current international guidelines recommend colonoscopy in patients with acromegaly at the time of diagnosis, even though the risk of developing colorectal neoplasm is still controversial. The main objective of this Argentine multicenter study was to analyze through screening colonoscopy the presence of advanced neoplastic lesions considered as precancerous, in patients with acromegaly compared to a control group.

METHODS

This is a case-control retrospective study. Full length colonoscopy of 70 acromegalic patients and 128 control subjects were studied. Polyps were classified into non pre-cancerous lesions and advance neoplastic lesions which included advanced adenomas (preneoplastic) and colorectal carcinomas.

RESULTS

Thirty three out of 70 acromegalic patients and 32 out of 128 subjects controls presented polyps in the colonoscopy [47.1% vs 25%, p = 0.002, OR 2.68]. Non precancerous polyps were found in 11 (15.7%) and 23 (17.9%) (p = 0.690), while advanced neoplastic lesions were found in 22 (31.4%) and 9 (7.0%) (p = 0,0001 - OR: 6.06) patients and controls respectively. Advanced adenomas and colorectal carcinomas were found in 18 (27.3%) and 9 (7.0%) (p = 0,0006-OR: 4,57), and 4 (5.7%) and 0 (0.0%) p = 0.0063) of patients and controls respectively. The presence of insulin resistance was the only statistically significant associated factor among acromegalic patients with and without colonic polyps.

CONCLUSIONS

Our findings show an increased risk of preneoplastic colonic lesions and colorectal carcinoma in patients with chronic and sustained GH excess compared to a control group. This supports the recommendation to perform screening colonoscopy at diagnosis of acromegaly.

THE PREVALENCE OF CANCER AND ITS RELATION TO DISEASE ACTIVITY IN PATIENTS WITH ACROMEGALY: TWO CENTERS' EXPERIENCE

OBJECTIVE

Acromegaly is characterized by increased serum concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Although animal studies have demonstrated a relationship between these hormones and cancer risk, the results of human studies evaluating cancer prevalence in acromegaly are inconsistent. We aimed to investigate the prevalence of malignant neoplasms in patients with acromegaly.

METHODS

Cancer risk was evaluated in a cohort of 280 patients (male/female: 120/160; mean age: 50.93 ± 12.07 years) with acromegaly. Patients were categorized into 2 groups according to the presence or absence of cancer. Standard incidence ratios were calculated as compared to the general population.

RESULTS

From 280 patients, cancer was diagnosed in 19 (6.8%) patients; 9 (47%) of them had thyroid cancer, which was the most common cancer type. Standard incidence ratios of all cancers were 0.8 (95% CI, 0.5-1.1) and 1.0 (95% CI, 0.8-1.3) in men and women, respectively. Compared to patients without cancer, the current age was higher in patients with cancer (59 [49-65] to 51 [42-59], P = .027). In contrast, the age at diagnosis was similar in both groups. Not only was the time to diagnosis and disease duration similar in both groups but also the basal and current GH and IGF-1 levels. The prevalence of active disease was also similar between the groups (32% to 23%, P = .394).

CONCLUSION

Our findings were not consistent with the studies suggesting that patients with acromegaly encounter an increased cancer risk. Furthermore, there were similar basal and current GH and IGF-1 levels in patients with acromegaly, both with and without cancer.

Epidemiology of Anthropometric Factors in Glioblastoma Multiforme-Literature Review

Although glioblastoma multiforme (GBM) is a widely researched cancer of the central nervous system, we still do not know its full pathophysiological mechanism and we still lack effective treatment methods as the current combination of surgery, radiotherapy, and chemotherapy does not bring about satisfactory results. The median survival time for GBM patients is only about 15 months. In this paper, we present the epidemiology of central nervous system (CNS) tumors and review the epidemiological data on GBM regarding gender, age, weight, height, and tumor location. The data indicate the possible influence of some anthropometric factors on the occurrence of GBM, especially in those who are male, elderly, overweight, and/or are taller. However, this review of single and small-size epidemiological studies should not be treated as definitive due to differences in the survey methods used. Detailed epidemiological registers could help identify the main at-risk groups which could then be used as homogenous study groups in research worldwide. Such research, with less distortion from various factors, could help identify the pathomechanisms that lead to the development of GBM.

Patient-Identified Problems and Influences Associated With Diagnostic Delay of Acromegaly: A Nationwide Cross-Sectional Study

BACKGROUND

Insidious-onset acromegaly may easily be overlooked by non-specialists of acromegaly and cause diagnostic delay. This study aims to examine the association between diagnostic delay and advice from doctors before any confirmed diagnosis and subsequent comorbidities, and elicit patient-perceived reasons for misdiagnoses.

METHODS

An online nationwide cross-sectional study was conducted through China Acromegaly Patient Association. Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) levels at diagnosis and cancerous, endocrine-metabolic, musculoskeletal, cardiovascular, respiratory, and psychiatric comorbidities were reported by patients. The association between diagnostic delay and pre-diagnostic advice from doctors as well as subsequent comorbidities after diagnosis were examined.

RESULTS

In total, 447 valid responses were collected. Overall, 58.8% patients experienced misdiagnoses, and 22.6% had diagnostic delay. Before arriving at any diagnosis, patients without treatment (adjusted odds ratio [AOR]: 3.66, 95% confidence interval [CI]: 1.30-10.33) or receiving treatment to symptoms only (AOR: 7.05, 95%CI: 4.09-12.17) had greater chance of being misdiagnosed, and hence had diagnostic delay. Patients believed insufficient specialists, limited awareness of acromegaly of non-specialists and poor doctor-patient communications were major reasons of misdiagnosis. Diagnostic delay were associated with higher GH level at diagnosis and endocrine-metabolic, musculoskeletal and cardiovascular comorbidities (all P<0.05).

CONCLUSIONS

Suboptimal pre-diagnostic advice for patients, reflecting limited awareness of acromegaly among non-specialists, may delay the diagnosis and increase comorbidities. Feedbacks on the patients' final diagnosis from specialists to non-specialists should be considered, and doctor-patient communication and clinical decision-making process should be improved. Comorbidities should be screened and monitored particularly for patients with diagnostic delay.

GH and IGF System: The Regulatory Role of miRNAs and lncRNAs in Cancer

Growth hormone (GH) and the insulin-like growth factor (IGF) system are involved in many biological processes and have growth-promoting actions regulating cell proliferation, differentiation, apoptosis and angiogenesis. A recent chapter in epigenetics is represented by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) which regulate gene expression. Dysregulated miRNAs and lncRNAs have been associated with several diseases including cancer. Herein we report the most recent findings concerning miRNAs and lncRNAs regulating GH and the IGF system in the context of pituitary adenomas, osteosarcoma and colorectal cancer, shedding light on new possible therapeutic targets. Pituitary adenomas are increasingly common intracranial tumors and somatotroph adenomas determine supra-physiological GH secretion and cause acromegaly. Osteosarcoma is the most frequent bone tumor in children and adolescents and was reported in adults who were treated with GH in childhood. Colorectal cancer is the third cancer in the world and has a higher prevalence in acromegalic patients.

Safety of Pediatric rhGH Therapy: An Overview and the Need for Long-Term Surveillance

Growth hormone (GH) therapy dates back to 1958 and, though has shown an excellent safety profile in the short-term, has never ceased to raise concern about potential long-term side effects. In the last decade, a number of observational studies in different cohorts of young adult patients treated with GH during childhood have yielded conflicting results. The attention has mainly focused on three major potential risks associated with GH therapy: cancer, cardio and cerebrovascular diseases and diabetes. This review intends to provide a detailed overview of the main studies reporting long-term safety in subjects treated with rhGH therapy during childhood, highlighting the evidence for or against the risk of cancer, cardio and cerebrovascular diseases and diabetes.

Neuroendocrine manifestations of Erdheim-Chester disease

Neuroendocrine manifestations are common in Erdheim-Chester disease (ECD) patients. ECD is a rare non-Langerhans form of histiocytosis with multisystemic infiltration. The involvement of the hypothalamo-pituitary axis is common and central diabetes insipidus (CDI) is one of the most common endocrine manifestations in ECD patients. CDI is the first manifestation of ECD in 25%-48% of the cases. Suprasellar region extension, due to the infiltration of ECD lesions, can cause neurologic manifestations by mass effects, such as headache, visual disturbance, and cranial nerve palsies. Recent studies have revealed that disorders affecting anterior pituitary hormones are common in ECD patients. Secondary adrenal insufficiency, secondary hypothyroidism, (adult) growth hormone deficiency, hypogonadotropic hypogonadism, hyperprolactinemia, and hypoprolactinemia can develop as the neuroendocrine manifestations of ECD. Since the symptoms of anterior pituitary hormone deficiencies tend to be nonspecific, the diagnosis of anterior pituitary hormone dysfunctions can be delayed. Some anterior pituitary dysfunctions such as adrenocorticotropic hormone and/or thyroid-stimulating hormone deficiencies can be life-threatening without adequate hormone supplementation therapies. An endocrinological evaluation of the function of the pituitary gland should be performed at the initial diagnosis of ECD. It is important to recognize that endocrine dysfunctions can develop later during the follow-up of ECD.

Growth Hormone Upregulates Mediators of Melanoma Drug Efflux and Epithelial-to-Mesenchymal Transition In Vitro and In Vivo

Simple Summary

Growth hormone (GH) action is strongly implicated in the progression and therapy resistance in several types of solid tumors which overexpress the GH receptor (GHR). The aim of our study was to characterize the effects of GH and its downstream effector insulin-like growth factor 1 (IGF-1) on melanoma using in vitro and in vivo models. We confirmed an IGF-1-independent role of elevated circulating GH in upregulating key mechanisms of therapy resistance and malignancy with analyses conducted at the molecular and cellular level. We identified that GH upregulates key mechanisms of therapy resistance and metastases in melanoma tumors in an IGF-1 dependent and independent manner by upregulating multidrug efflux pumps and EMT transcription factors. Our study reveals that GH action renders an intrinsic drug resistance phenotype to the melanoma tumors—a clinically crucial property of GH verifiable in other human cancers with GHR expression.

Abstract

Growth hormone (GH) and the GH receptor (GHR) are expressed in a wide range of malignant tumors including melanoma. However, the effect of GH/insulin-like growth factor (IGF) on melanoma in vivo has not yet been elucidated. Here we assessed the physical and molecular effects of GH on mouse melanoma B16-F10 and human melanoma SK-MEL-30 cells in vitro. We then corroborated these observations with syngeneic B16-F10 tumors in two mouse lines with different levels of GH/IGF: bovine GH transgenic mice (bGH; high GH, high IGF-1) and GHR gene-disrupted or knockout mice (GHRKO; high GH, low IGF-1). In vitro, GH treatment enhanced mouse and human melanoma cell growth, drug retention and cell invasion. While the in vivo tumor size was unaffected in both bGH and GHRKO mouse lines, multiple drug-efflux pumps were up regulated. This intrinsic capacity of therapy resistance appears to be GH dependent. Additionally, epithelial-to-mesenchymal transition (EMT) gene transcription markers were significantly upregulated in vivo supporting our current and recent in vitro observations. These syngeneic mouse melanoma models of differential GH/IGF action can be valuable tools in screening for therapeutic options where lowering GH/IGF-1 action is important.

The role of acid-labile subunit (ALS) in the modulation of GH-IGF-I action

Acid-labile subunit (ALS) deficiency (ACLSD) constitutes the first monogenic defect involving a member of the Insulin-like Growth Factor (IGF) binding protein system. The lack of ALS completely disrupts the circulating IGF system. Autocrine/paracrine action of local produced IGF-I could explain the mild effect on growth. In the present work we have revised the more relevant clinical and biochemical consequences of complete ACLSD in 61 reported subjects from 31 families. Low birth weight and/or length, reduced head circumference, height between -2 and -3 SD, pubertal delay and insulin resistance are commonly observed. Partial ACLSD could be present in children initially labeled as idiopathic short stature, presenting low IGF-I levels, suggesting that one functional IGFALS allele is insufficient to stabilize ternary complexes. Dysfunction of the GH-IGF axis observed in ACLSD may eventually result in increased risk for type-2 diabetes and tumor progression. Consequently, long term surveillance is recommended in these patients.

Role of the GH-IGF1 system in progression of cancer

Emerging evidence links the growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis to cancer development. While this putative correlation is of major translational relevance, most clinical and epidemiological reports to date found no causal linkage between GH therapy and enhanced cancer risk. Thus, it is generally agreed that GH therapy constitutes a safe pharmacological intervention. The present review focuses on a number of issues in the area of GH-IGF1 action in cancer development. Emphasis is given to the idea that GH and IGF1 do not conform to the definition of oncogenic factors. Specifically, these hormones, even at high pharmacological doses, are unable to induce malignant transformation. However, the GH-IGF1 axis is capable of 'pushing' already transformed cells through the various phases of the cell cycle. Viral and cellular oncogenes require an intact IGF1 signaling pathway in order to elicit transformation; in other words, oncogenic agents adopt the IGF1 pathway. This universal mechanism of action of oncogenes has broad implications in oncology. Our review provides an in-depth analysis of the interplay between the GH-IGF1 axis and cancer genes, including tumor suppressors p53 and BRCA1. Finally, the safety of GH therapy in both children and adults needs further long-term follow-up studies.

Identification of nephronectin as a new target for IGF1 action

INTRODUCTION

The growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis has a key role in normal growth and development. Laron syndrome (LS) is a type of dwarfism that results from mutation of the GH receptor, leading to congenital IGF1 deficiency. Epidemiological studies have shown that LS patients are protected from cancer. Genome-wide profiling led to the identification of a series of metabolic genes whose differential expression in LS might be linked to cancer protection. Nephronectin (NPNT) is an intracellular and secreted extracellular matrix protein with important roles in kidney development. NPNT was identified as the top-downregulated gene in LS-derived cells in comparison with ethnic-, age- and gender-matched controls (p-value = 0.0148; fold-change = -3.12 versus controls). NPNT has not been previously linked to the IGF1 signaling pathway. The present study was aimed at evaluating the hypothesis that NPNT is a new target for IGF1 action and that decreased expression of NPNT in LS is correlated with cancer protection.

METHODS

Basal and IGF1-stimulated NPNT expression were assessed in LS lymphoblastoid cells as well as in human breast and prostate cancer cells. NPNT silencing experiments were conducted using siRNA methodology.

RESULTS

We provide evidence that IGF1 stimulates NPNT expression in LS-derived lymphoblastoids and various cancer cell lines. In addition, we demonstrate that NPNT silencing results in diminished activation of the AKT and ERK1/2 pathways, with ensuing decreases in cellular proliferation.

CONCLUSIONS

Our data identified the NPNT gene as a target for IGF1 action. The clinical implications of the functional and physical interactions between NPNT and the IGF1 pathway merit further investigation.

Differentiated thyroid carcinoma in sporadic and familial presentations of acromegaly: A case series

BACKGROUND

In acromegaly, chronic growth hormone (GH) and insulin-like growth factor-1 (IGF-1) exacerbate comorbidities in multiple organs. Differentiated thyroid carcinoma (DTC) has been reported as being a comorbid condition in acromegaly. Acromegaly is usuallysporadic, but 5% of cases may be genetic. The most frequent inheritable form of acromegaly is related to germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene. Epidemiological data on the relationship between active acromegaly, its familial forms and DTC are sparse. We present the investigation of a FIPA family (familial isolated pituitary adenoma) with homogeneous acromegaly and 6 sporadic acromegaly patients with DTC.

PATIENTS AND METHODS

A study of 59 acromegaly patients assessed thyroid nodules on ultrasound and fine-needle aspiration biopsy following the ATA 2015 criteria. We diagnosed 7 differentiated thyroid carcinomas. Resected thyroid carcinoma tissues were stained using an anti-AIP antibody. Analysis of germline and tumor-derived DNA for variants in the AIP and MEN1 genes were performed in the FIPA kindred.

RESULTS

We describe one FIPA patient and 6 sporadic acromegaly cases with DTC. The FIPA family (AIP mutation negative) consisted of two sisters, one of whom had a DTC with intermediate risk and incomplete structural response to therapy. In our study, DTC in sporadic acromegaly had a low recurrence rate (6/6), and excellent response to therapy (6/6). Immunohistochemistry for AIP showed similar or increased staining intensity in DTC versus normal thyroid tissue.

CONCLUSION

In our cohort of sporadic and familial forms of acromegaly with DTC, AIP did not appear to influence thyroid cancer progression.

The tumour microenvironment of pituitary neuroendocrine tumours

The tumour microenvironment (TME) includes a variety of non-neoplastic cells and non-cellular elements such as cytokines, growth factors and enzymes surrounding tumour cells. The TME emerged as a key modulator of tumour initiation, progression and invasion, with extensive data available in many cancers, but little is known in pituitary tumours. However, the understanding of the TME of pituitary tumours has advanced thanks to active research in this field over the last decade. Different immune and stromal cell subpopulations, and several cytokines, growth factors and matrix remodelling enzymes, have been characterised in pituitary tumours. Studying the TME in pituitary tumours may lead to a better understanding of tumourigenic mechanisms, identification of biomarkers useful to predict aggressive disease, and development of novel therapies. This review summarises the current knowledge on the different TME cellular/non-cellular elements in pituitary tumours and provides an overview of their role in tumourigenesis, biological behaviour and clinical outcomes.

Diagnosis and Treatment of Growth Hormone Deficiency: A Position Statement from Korean Endocrine Society and Korean Society of Pediatric Endocrinology

Growth hormone (GH) deficiency is caused by congenital or acquired causes and occurs in childhood or adulthood. GH replacement therapy brings benefits to body composition, exercise capacity, skeletal health, cardiovascular outcomes, and quality of life. Before initiating GH replacement, GH deficiency should be confirmed through proper stimulation tests, and in cases with proven genetic causes or structural lesions, repeated GH stimulation testing is not necessary. The dosing regimen of GH replacement therapy should be individualized, with the goal of minimizing side effects and maximizing clinical improvements. The Korean Endocrine Society and the Korean Society of Pediatric Endocrinology have developed a position statement on the diagnosis and treatment of GH deficiency. This position statement is based on a systematic review of evidence and expert opinions.

Fertility issues in aggressive pituitary tumors

The management of aggressive pituitary adenomas represents a special clinical challenge, and usually involves a combination of surgery, radiotherapy and pharmacological agents to control tumor growth and hormone abnormalities. Fertility is commonly affected in these patients due to compressive effects of the tumor, pituitary hormone dysfunction or as a result of the multiple therapies. The initial approach to restore fertility involves the reduction of tumor volume by the use of dopamine agonists in prolactinomas and by surgery in other pituitary adenomas. Somatostatin analogues are alternative options for GH, ACTH and TSH-secreting tumors. When present, pituitary deficiencies should be appropriately treated, particularly GH deficiency that has been associated with poor pregnancy rates in hypopituitary patients. Other therapies for aggressive pituitary tumors, such as invasive surgery, radiotherapy and temozolamide, may lead to infertility. In such cases, fertility preservation strategies might be considered and discussed with the patient desiring conception before or during treatment. In men and women with hypogonadotropic hypogonadism, administration of gonadotropins or pulse GnRH has resulted in satisfactory pregnancy rates. If spontaneous gestation is not achieved, assisted reproduction techniques can be employed as the last line of treatment. In any context, pre-conception counseling and care are essential as pregnancies in women with aggressive pituitary tumors should always be considered high risk.

Exposure to growth hormone is associated with hepatic up-regulation of cPLA2α and COX

Continuously elevated levels of growth hormone (GH) during life in mice are associated with hepatomegaly due to hepatocytes hypertrophy and hyperplasia, chronic liver inflammation, elevated levels of arachidonic acid (AA) at young ages and liver tumors development at old ages. In this work, the hepatic expression of enzymes involved in AA metabolism, cPLA2α, COX1 and COX2 enzymes, was evaluated in young and old GH-transgenic mice. Mice overexpressing GH exhibited higher hepatic expression of cPLA2α, COX1 and COX2 in comparison to controls at young and old ages and in both sexes. In old mice, when tumoral and non-tumoral tissue were compared, elevated expression of COX2 was observed in tumors. In contrast, exposure to continuous lower levels of hormone for a short period affected COX1 expression only in males. Considering the role of inflammation during liver tumorigenesis, these findings support a role of alterations in AA metabolism in GH-driven liver tumorigenesis.

OFF-LABEL USE AND MISUSE OF TESTOSTERONE, GROWTH HORMONE, THYROID HORMONE, AND ADRENAL SUPPLEMENTS: RISKS AND COSTS OF A GROWING PROBLEM

Over the past few decades, there has been an unprecedented rise in off-label use and misuse of testosterone, growth hormone, thyroid hormone, and adrenal supplements. Testosterone therapy is often promoted to men for the treatment of low energy, lower libido, erectile dysfunction, and other symptoms. Growth hormone is used in attempts to improve athletic performance in athletes and to attenuate aging in older adults. Thyroid hormone and/or thyroid supplements or boosters are taken to treat fatigue, obesity, depression, cognitive impairment, impaired physical performance, and infertility. Adrenal supplements are used to treat common nonspecific symptoms due to "adrenal fatigue," an entity that has not been recognized as a legitimate medical diagnosis. Several factors have contributed to the surge in off-label use and misuse of these hormones and supplements: direct-to-consumer advertising, websites claiming to provide legitimate medical information, and for-profit facilities promoting therapies for men's health and anti-aging. The off-label use and misuse of hormones and supplements in individuals without an established endocrine diagnosis carries known and unknown risks. For example, the risks of growth hormone abuse in athletes and older adults are unknown due to a paucity of studies and because those who abuse this hormone often take supraphysiologic doses in sporadic intervals. In addition to the health risks, off-label use of these hormones and supplements generates billions of dollars of unnecessary costs to patients and to the overall health-care system. It is important that patients honestly disclose to their providers off-label hormone use, as it may affect their health and treatment plan. General medical practitioners and adult endocrinologists should be able to begin a discussion with their patients regarding the unfavorable balance between the risks and benefits associated with off-label use of testosterone, growth hormone, thyroid hormone, and adrenal supplements. Abbreviations: DHEA = dehydroepiandrosterone; FDA = U.S. Food and Drug Administration; GH = growth hormone; IGF-1 = insulin-like growth factor 1; LT3 = L-triiodothyronine; LT4 = levothyroxine; T3 = total triiodothyronine; T4 = thyroxine; TSH = thyroid-stimulating hormone.

A Consensus on the Diagnosis and Treatment of Acromegaly Comorbidities: An Update

OBJECTIVE

The aim of the Acromegaly Consensus Group was to revise and update the consensus on diagnosis and treatment of acromegaly comorbidities last published in 2013.

PARTICIPANTS

The Consensus Group, convened by 11 Steering Committee members, consisted of 45 experts in the medical and surgical management of acromegaly. The authors received no corporate funding or remuneration.

EVIDENCE

This evidence-based consensus was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence following critical discussion of the current literature on the diagnosis and treatment of acromegaly comorbidities.

CONSENSUS PROCESS

Acromegaly Consensus Group participants conducted comprehensive literature searches for English-language papers on selected topics, reviewed brief presentations on each topic, and discussed current practice and recommendations in breakout groups. Consensus recommendations were developed based on all presentations and discussions. Members of the Scientific Committee graded the quality of the supporting evidence and the consensus recommendations using the GRADE system.

CONCLUSIONS

Evidence-based approach consensus recommendations address important clinical issues regarding multidisciplinary management of acromegaly-related cardiovascular, endocrine, metabolic, and oncologic comorbidities, sleep apnea, and bone and joint disorders and their sequelae, as well as their effects on quality of life and mortality.

Impact of Pituitary Autoimmunity and Genetic Disorders on Growth Hormone Deficiency in Children and Adults

Growth hormone (GH), mostly through its peripheral mediator, the insulin-like growth factor 1(IGF1), in addition to carrying out its fundamental action to promote linear bone growth, plays an important role throughout life in the regulation of intermediate metabolism, trophism and function of various organs, especially the cardiovascular, muscular and skeletal systems. Therefore, if a prepubertal GH secretory deficiency (GHD) is responsible for short stature, then a deficiency in adulthood identifies a nosographic picture classified as adult GHD syndrome, which is characterized by heart, muscle, bone, metabolic and psychic abnormalities. A GHD may occur in patients with pituitary autoimmunity; moreover, GHD may also be one of the features of some genetic syndromes in association with other neurological, somatic and immune alterations. This review will discuss the impact of pituitary autoimmunity on GHD and the occurrence of GHD in the context of some genetic disorders. Moreover, we will discuss some genetic alterations that cause GH and IGF-1 insensitivity and the arguments in favor and against the influence of GH/IGF-1 on longevity and cancer in the light of the papers on these issues that so far appear in the literature.

From dwarves to giants: South American's contribution to the history of growth hormone and related disorders

The aim of this article is to present a historical review on giants and dwarves living in South America and the contribution of South America's researchers to scientific advances on growth hormone (GH) and human disorders related to GH excess and GH deficiency (GHD). We went back in time to investigate facts and myths stemming from countless reports of giants who lived in the Patagonia region, focusing on what is currently known about gigantism in South America. Additionally, we have reviewed the exceptional work carried out in two of the world's largest cohorts of dwarfism related to GH-IGF axis: one living in Itabaianinha, Brazil, suffering from severe GHD due to a mutation in the GHRH receptor (GHRHR) gene, and the other living in El Oro and Loja provinces of Ecuador, who are carriers of GH receptor gene mutation that causes total GH insensitivity (Laron syndrome). Importantly, we present an overview of the outstanding medical contribution of Jose Dantas de Souza Leite, a Brazilian physician that described the first cases of acromegaly, and Bernardo Alberto Houssay, an Argentine researcher graced with the Nobel Prize, who was one the first scientists to establish a link between GH and glucose metabolism.

Acromegaly in the elderly patient

Acromegaly is an insidious disease, usually resulting from growth hormone hypersecretion by a pituitary adenoma. It is most often diagnosed during the 3rd to 4th decade of life. However, recent studies have shown an increase in the incidence and prevalence of acromegaly in the elderly, probably due to increasing life expectancy. As in the younger population with acromegaly, there is a delay in diagnosis, aggravated by the similarities of the aging process with some of the characteristics of the disease. As can be expected elderly patients with acromegaly have a higher prevalence of comorbidities than younger ones. The diagnostic criteria are the same as for younger patients. Surgical treatment of the pituitary adenoma is the primary therapy of choice unless contraindicated. Somatostatin receptor ligands are generally effective as both primary and postoperative treatment. The prognosis correlates inversely with the patient's age, disease duration and last GH level. Arch Endocrinol Metab. 2019;63(6):638-45.

Adult growth hormone deficiency: clinical advances and approaches to improve adherence

Introduction: There have been significant clinical advances in the understanding of the diagnosis and benefits of long-term recombinant human growth hormone (rhGH) replacement in adults with GH deficiency (GHD) since its approval in 1996 by the United States Food and Drug Administration.Areas covered: We searched PubMed, Medline, CINAHL, EMBASE and PsychInfo databases between January 2000 and June 2019 for published studies evaluating adults with GHD. We reviewed the data of the oral macimorelin test compared to the GHRH plus arginine and the insulin tolerance tests that led to its approval by the United States FDA and European Medicines Agency for adult diagnostic testing. We summarize the clinical advances of long-term benefits of rhGH therapy and the potential effects of GH receptor polymorphisms on individual treatment responsiveness. We identify that non-adherence and discontinuation rates are high and recommend strategies to support patients to improve adherence. We also provide an overview of several long-acting GH (LAGH) preparations currently under development and their potential role in improving treatment adherence.Expert opinion: This article summarizes recent clinical advances in rhGH replacement therapy, the biological and molecular aspects that may influence rhGH action, and offers practical strategies to enhance adherence in adults with GHD.

Growth hormone in the tumor microenvironment

Tumor development is a multistep process whereby local mechanisms enable somatic mutations during preneoplastic stages. Once a tumor develops, it becomes a complex organ composed of multiple cell types. Interactions between malignant and non-transformed cells and tissues create a tumor microenvironment (TME) comprising epithelial cancer cells, cancer stem cells, non-tumorous cells, stromal cells, immune-inflammatory cells, blood and lymphatic vascular network, and extracellular matrix. We review reports and present a hypothesis that postulates the involvement of growth hormone (GH) in field cancerization. We discuss GH contribution to TME, promoting epithelial-to-mesenchymal transition, accumulation of unrepaired DNA damage, tumor vascularity, and resistance to therapy. Arch Endocrinol Metab. 2019;63(6):568-75.

Pyruvate kinase M2: A simple molecule with complex functions

Pyruvate kinase M2 is a critical enzyme that regulates cell metabolism and growth under different physiological conditions. In its metabolic role, pyruvate kinase M2 catalyzes the last glycolytic step which converts phosphoenolpyruvate to pyruvate with the generation of ATP. Beyond this metabolic role in glycolysis, PKM2 regulates gene expression in the nucleus, phosphorylates several essential proteins that regulate major cell signaling pathways, and contribute to the redox homeostasis of cancer cells. The expression of PKM2 has been demonstrated to be significantly elevated in several types of cancer, and the overall inflammatory response. The unusual pattern of PKM2 expression inspired scientists to investigate the unrevealed functions of PKM2 and the therapeutic potential of targeting PKM2 in cancer and other disorders. Therefore, the purpose of this review is to discuss the mechanistic and therapeutic potential of targeting PKM2 with the focus on cancer metabolism, redox homeostasis, inflammation, and metabolic disorders. This review highlights and provides insight into the metabolic and non-metabolic functions of PKM2 and its relevant association with health and disease.

The effects of growth hormone on therapy resistance in cancer

Pituitary derived and peripherally produced growth hormone (GH) is a crucial mediator of longitudinal growth, organ development, metabolic regulation with tissue specific, sex specific, and age-dependent effects. GH and its cognate receptor (GHR) are expressed in several forms of cancer and have been validated as an anti-cancer target through a large body of in vitro, in vivo and epidemiological analyses. However, the underlying molecular mechanisms of GH action in cancer prognosis and therapeutic response had been sparse until recently. This review assimilates the critical details of GH-GHR mediated therapy resistance across different cancer types, distilling the therapeutic implications based on our current understanding of these effects.

Insulin Resistance in Patients With Acromegaly

Acromegaly is characterized by chronic overproduction of growth hormone (GH) that leads to insulin resistance, glucose intolerance and, ultimately, diabetes. The GH-induced sustained stimulation of lipolysis plays a major role not only in the development of insulin resistance and prediabetes/diabetes, but also in the reduction of lipid accumulation, making acromegaly a unique case of severe insulin resistance in the presence of reduced body fat. In the present review, we elucidate the effects of GH hypersecretion on metabolic organs, describing the pathophysiology of impaired glucose tolerance in acromegaly, as well as the impact of acromegaly-specific therapies on glucose metabolism. In addition, we highlight the role of insulin resistance in the development of acromegaly-associated complications such as hypertension, cardiac disease, sleep apnea, polycystic ovaries, bone disease, and cancer. Taken together, insulin resistance is an important metabolic hallmark of acromegaly, which is strongly related to disease activity, the development of comorbidities, and might even impact the response to drugs used in the treatment of acromegaly.