Skeletal maturation in children with Cushing syndrome is not consistently delayed: the role of corticotropin, obesity, and steroid hormones, and the effect of surgical cure.

OBJECTIVE: To assess skeletal maturity by measuring bone age (BA) in children with Cushing syndrome (CS) before and 1-year after transsphenoidal surgery or adrenalectomy, and to correlate BA with hormone levels and other measurements. STUDY DESIGN: This case series conducted at the National Institutes of Health Clinical Center included 93 children with Cushing disease (CD) (43 females; mean age, 12.3 ± 2.9 years) and 31 children with adrenocorticotropic hormone-independent CS (AICS) (22 females, mean age 10.3 ± 4.5 years). BA was obtained before surgery and at follow-up. Outcome measures were comparison of BA in CD vs AICS and analysis of the effects of hypercortisolism, insulin excess, body mass index, and androgen excess on BA. RESULTS: Twenty-six of the 124 children (21.0%) had advanced BA, compared with the expected general population prevalence of 2.5% (P < .0001). Only 4 of 124 (3.2%) had delayed BA. The majority of children (76%) had normal BA. The average BA z-score was similar in the children with CD and those with AICS (0.6 ± 1.4 vs 0.5 ± 1.8; P = .8865). Body mass index SDS and normalized values of dehydroepiandrosterone, dehydroepiandrosterone sulfate, androsteonedione, estradiol, and testosterone were all significantly higher in the children with advanced BA vs those with normal or delayed BA. Fifty-nine children who remained in remission from CD had follow-up BA 1.2 ± 0.3 years after transsphenoidal surgery, demonstrating decreased BA z-score (1.0 ± 1.6 vs 0.3 ± 1.4; P < .0001). CONCLUSION: Contrary to common belief, endogenous CS in children appears to be associated with normal or even advanced skeletal maturation. When present, BA advancement in CS is related to obesity, insulin resistance, and elevated adrenal androgen levels and aromatization. This finding may have significant implications for treatment decisions and final height predictions in these children.

Unique gene expression profile associated with an early-onset multiple endocrine neoplasia (MEN1)-associated pituitary adenoma.

CONTEXT: Multiple endocrine neoplasia type 1 (MEN1) is caused by mutations in the menin (MEN1) gene. The mechanism(s) by which MEN1 mutations lead to pituitary tumor formation remain(s) unknown. OBJECTIVE: The aim of the study was to identify the pediatric MEN1-associated pituitary tumor transcriptome. PATIENTS AND METHODS: A patient harboring a MEN1 mutation (c.525C>G; p.H139D) who presented with an early-onset mammosomatotroph pituitary adenoma was studied. Microarray analysis was performed in the tumor sample and compared with the profile observed in normal pituitaries and in a sporadic mammosomatotropinoma. Validation of the microarray results was performed using quantitative real-time PCR and immunohistochemical analysis for selected genes. RESULTS: In the MEN1-associated pituitary adenoma, 59 and 24 genes were found to be significantly up- and down-regulated, respectively. The up-regulated genes included those involved in cell growth and maintenance, apoptosis, growth arrest, and tumorigenesis. Moreover, we observed decreased expression in genes neuroendocrine in nature and related to growth or apoptosis. Only 21 of the 59 genes differentially expressed in the MEN1-associated adenoma showed a similar expression profile to that seen in the sporadic mammosomatotropinoma; for some genes an opposite expression profile was observed. CONCLUSIONS: We identified changes in the transcriptome that occur in pituitary GH- and PRL-producing cells after the loss of menin expression; some of the gene changes are necessary for tumor evolution, and others may be tertiary. Nevertheless, the rare overlap between the expression profiles of the MEN1 tumor vs. that of its sporadic counterpart suggests that these tumors evolve along different molecular pathways.

Postoperative testing to predict recurrent Cushing disease in children.

CONTEXT: Postoperative testing after transsphenoidal surgery (TSS) for Cushing disease (CD) in children and its usefulness in predicting residual disease or recurrence are not well studied. OBJECTIVE: The objective of the study was to identify which one of three tests that are routinely performed in our institution after TSS performs better in the identification of noncured patients or predict relapse for CD. DESIGN: This was a retrospective review of clinical data of 72 children who received surgery for CD (age range 5.8-18.3 yr). SETTING: The study was conducted at a tertiary care center. METHODS: After TSS, plasma ACTH and serum cortisol (at 0800 h), urinary free cortisol (UFC) values and an ovine CRH (oCRH) stimulation test were obtained. Patients were followed up for 24-120 months by a formal protocol. RESULTS: Of 72 children with CD, 66 (94%) achieved sustained remission after TSS. Two children had persistent disease after TSS, whereas four children appeared cured at first but relapsed later. All four had low or undetectable UFCs that were not different from cured patients (P > 0.0.1). Children who remained in remission had significantly lower morning ACTH and cortisol levels after TSS compared with those who relapsed (P < 0.001). During an oCRH stimulation test, ACTH and cortisol values were higher in patients who relapsed vs. those in remission (P <0.001). Lack of histological confirmation of an adenoma, normal serum cortisol or ACTH, a normal response to oCRH, and glucocorticoid replacement for less than 6 months after surgery were associated with relapse. CONCLUSION: In pediatric patients with CD, low UFCs after TSS are not good predictors of sustained remission; morning ACTH and cortisol values and/or an oCRH test after TSS predicted patients that recurred.

Blood pressure in pediatric patients with Cushing syndrome.

CONTEXT: Hypertension (HTN) has been reported in up to 60% of children with Cushing syndrome (CS), but its course, side effects, and potential differences among various causes of CS have not been adequately studied. OBJECTIVE: The objective of the study was to measure blood pressure in pediatric patients with CS before and after transphenoidal surgery or adrenalectomy and identify side effects and rates of residual HTN. DESIGN: Data from 86 children with corticotropinomas [Cushing disease (CD)] and 27 children with ACTH-independent CS (AICS) were analyzed. RESULTS: Patients with CD and AICS had significant HTN before surgery; more patients with AICS had systolic HTN (SHTN) than with CD (74 vs. 44%, P = 0.0077), but the rate of diastolic HTN (DHTN) was similar. Both groups experienced significant decreases in SHTN immediately after transphenoidal surgery and adrenalectomy. One year postoperatively, both SHTN and DHTN were lower than the preoperative values in all patients, but as many as 16 and 4% of the patients with CD and 21 and 5% of the patients with AICS still had SHTN and DHTN, respectively. Higher blood pressure preoperatively correlated with cortisol levels. Two patients suffered serious side effects: one with multiple infarcts and another with hypertensive encephalopathy. CONCLUSIONS: Children with CS are at risk for residual HTN despite a significant improvement after surgical cure. HTN appears to correlate with the degree of hypercortisolemia. Serious HTN-related side effects, although rare, may occur during the perioperative period.

Severe obesity confounds the interpretation of low-dose dexamethasone test combined with the administration of ovine corticotrophin-releasing hormone in childhood Cushing syndrome.

CONTEXT: Suppression of cortisol secretion with a low-dose dexamethasone (Dex) followed by the administration of ovine CRH (Dex-oCRH) is used in the evaluation of adults with a pseudo-Cushing syndrome state (PCSS) vs. Cushing syndrome (CS). OBJECTIVE: The aim of the study was to determine the value of Dex-oCRH testing in the investigation of childhood CS. DESIGN: We conducted a retrospective analysis of data from children evaluated for CS vs. PCSS from 1998-2006; body mass index Z (BMIZ) and height-for-age Z (HAZ) scores were estimated. SETTING: A clinical research center was the setting for the study. MAIN OUTCOME MEASURES: The main outcomes were confirmation of the diagnosis of CS by histology and response to Dex-oCRH. RESULTS: Thirty-two children (ages 3-17 yr) were studied: 11 had CS and 21 had PCSS; of the latter, 11 had a BMIZ score greater than 2. Children with CS had a mean HAZ score of -1.3+/-0.51 vs. 0.31+/-0.38 in nonobese and 0.71+/-0.39 in obese children (P<0.001). The previously established criterion of a cortisol of 1.4 microg/dl (38 nmol/liter) after Dex-oCRH identified all 10 normal children who were not very obese and those with CS; 5 of 11 normal children with more severe obesity had cortisol values greater than 1.4 microg/dl (38 nmol/liter) after Dex-oCRH, lowering the test specificity to 55%. Without consideration for obesity, an increase of the cutoff cortisol value after Dex-oCRH to 3.2 microg/dl (88 nmol/liter) will have 91% sensitivity and 95% specificity; the corresponding values for a cutoff of 2.2 microg/dl (61 nmol/liter) were 100 and 90.5%, respectively. CONCLUSION: Our study showed that height gain is a simple way of distinguishing children with PCCS from those with CS; the interpretation of Dex-oCRH in children is confounded by severe obesity, which limits the utility of this test.

Selective loss of MEG3 expression and intergenic differentially methylated region hypermethylation in the MEG3/DLK1 locus in human clinically nonfunctioning pituitary adenomas.

CONTEXT: MEG3 is an imprinted gene encoding a novel noncoding RNA that suppresses tumor cell growth. Although highly expressed in the normal human pituitary, it is unknown which of the normal pituitary cell types and pituitary tumors express MEG3. OBJECTIVES: Our objectives were 1) to investigate cell-type- and tumor-type-specific expression of MEG3 in the human pituitary and 2) to investigate whether methylation in the intergenic differentially methylated region (IG-DMR) at the DLK1/MEG3 locus is involved in the loss of MEG3 expression in tumors. DESIGN AND METHODS: RT-PCR, quantitative RT-PCR, Northern blot, and a combination of in situ hybridization and immunofluorescence were used to determine the cell-type- and tumor-type-specific MEG3 expression. Bisulfite treatment and PCR sequencing of genomic DNA were used to measure the CpG methylation status in the normal and tumor tissues. Five normal human pituitaries and 17 clinically nonfunctioning, 11 GH-secreting, seven prolactin-secreting, and six ACTH-secreting pituitary adenomas were used. RESULTS: All normal human pituitary cell types express MEG3. However, loss of MEG3 expression occurs only in nonfunctioning pituitary adenomas of a gonadotroph origin. All other pituitary tumor phenotypes examined express MEG3. Hypermethylation of the IG-DMR at the DLK1/MEG3 locus is present in nonfunctioning pituitary adenomas. CONCLUSIONS: MEG3 is the first human gene identified expressed in multiple normal human pituitary cell types with loss of expression specifically restricted to clinically nonfunctioning pituitary adenomas. The IG-DMR hypermethylation may be an additional mechanism for MEG3 gene silencing in such tumors.

Diagnostic tests for children who are referred for the investigation of Cushing syndrome.

OBJECTIVE: Endogenous Cushing syndrome in children is a rare disorder that is most frequently caused by pituitary or adrenocortical tumors. Diagnostic criteria have generally been derived from studies of adult patients despite significant differences in both the physiology of the hypothalamic-pituitary-adrenal axis and the epidemiology of Cushing syndrome in childhood. The purpose of this study was to identify the tests that most reliably and efficiently diagnose pituitary or adrenal tumors in a large cohort of pediatric patients with Cushing syndrome. METHODS: A retrospective review of clinical data of children who were referred to a tertiary care center for evaluation for Cushing syndrome during the years 1997 to 2005 was conducted. A total of 125 consecutive children were studied retrospectively; 105 were found to have Cushing syndrome, which was confirmed histologically; and 20 children who did not have Cushing syndrome or any other endocrinopathy served as the control group. The following tests were performed in all children: midnight and morning cortisol, corticotropin hormone, urinary free cortisol and 17-hydroxycorticosteroid levels, ovine corticotropin-releasing hormone stimulation test, and overnight high-dosage dexamethasone suppression test. Imaging of the pituitary and adrenal glands was also obtained. The main outcome measure was the sensitivity of these parameters for the diagnosis and differential diagnosis of Cushing syndrome at 100% specificity. RESULTS: A midnight cortisol value of > or = 4.4 microg/dL confirmed the diagnosis of Cushing syndrome in almost all children, with a sensitivity of 99% and a specificity of 100%. Suppression of morning cortisol levels > 20% in response to an overnight, high-dosage dexamethasone test excluded all patients with adrenal tumors and identified almost all patients with pituitary tumors (sensitivity: 97.5%; specificity: 100%). CONCLUSIONS: Our study suggests that among children who were referred for the evaluation of possible Cushing syndrome, a single cortisol value at midnight followed by overnight high-dosage dexamethasone test led to rapid and accurate confirmation and diagnostic differentiation, respectively, of hypercortisolemia caused by pituitary and adrenal tumors.

Activation of p53 by MEG3 non-coding RNA.

MEG3 is a maternally expressed imprinted gene suggested to function as a non-coding RNA. Our previous studies suggest that MEG3 has a function of tumor suppression. The tumor suppressor p53 plays a central role in tumor suppression and mediates the functions of many other tumor suppressors. Therefore, we hypothesized that MEG3 functions through activation of p53. We found that transfection of expression constructs for MEG3 and its isoforms results in a significant increase in p53 protein levels and dramatically stimulates p53-dependent transcription from a p53-responsive promoter. Using this as the functional assay, we demonstrated that the open reading frames encoded by MEG3 transcripts are not required for MEG3 function, and the folding of MEG3 RNA is critical to its function, supporting the concept that MEG3 functions as a non-coding RNA. We further found that MEG3 stimulates expression of the growth differentiation factor 15 (GDF15) by enhancing p53 binding to the GDF15 gene promoter. Interestingly, MEG3 does not stimulate p21(CIP1) expression, suggesting that MEG3 can regulate the specificity of p53 transcriptional activation. p53 degradation is mainly mediated by the mouse double minute 2 homolog (MDM2). We found that MDM2 levels were down-regulated in cells transfected with MEG3, suggesting that MDM2 suppression contributes at least in part to p53 accumulation induced by MEG3. Finally, we found that MEG3 is able to inhibit cell proliferation in the absence of p53. These data suggest that MEG3 non-coding RNA may function as a tumor suppressor, whose action is mediated by both p53-dependent and p53-independent pathways.

Endocrine abnormalities in patients with Fanconi anemia.

BACKGROUND: Fanconi anemia (FA) is an inherited disorder with chromosomal instability, bone marrow failure, developmental defects, and a predisposition to cancer. Systematic and comprehensive endocrine function data in FA are limited. OBJECTIVE: We studied a cohort of FA patients enrolled in the National Cancer Institute's Inherited Bone Marrow Failure Syndrome study. STUDY DESIGN AND PATIENTS: Retrospective review of the medical records of 45 FA patients (ages 2-49 yr), 23 of whom were intensively evaluated at the National Institutes of Health. Anthropometric measurements, GH, IGF-I, IGF binding protein-3, thyroid, gonadal hormone, lipid levels, glucose homeostasis, brain imaging, and bone mineral density were obtained in these latter patients. RESULTS: Endocrine abnormalities were present in 73%, including short stature and/or GH deficiency (51%), hypothyroidism (37%), midline brain abnormalities (17%) (these patients had very short stature and 60% were GH-deficient); abnormal glucose/insulin metabolism (39%); obesity (27%); dyslipidemia (55%); and metabolic syndrome (21%). Patients with any endocrine abnormality were shorter than those without; only GH deficiency correlated significantly with short stature (P = 0.01). In addition, 65% of peripubertal or postpubertal patients had gonadal dysfunction. Ninety-two percent of the patients 18 yr or older had osteopenia or osteoporosis. CONCLUSIONS: Endocrine dysfunction is widespread in children and adults with FA; we expand the FA phenotype to include early onset osteopenia/osteoporosis and lipid abnormalities. Despite the reputation of FA as a progressive, lethal disease, proper management of the full spectrum of FA-related endocrinopathy offers major opportunities to reduce morbidity and improve quality of life. Our findings emphasize the need for comprehensive endocrine and metabolic evaluation and long-term follow-up in patients with FA.

The effects of SOM230 on cell proliferation and adrenocorticotropin secretion in human corticotroph pituitary adenomas.

CONTEXT: There is no tumor-directed medical therapy available for Cushing's disease. OBJECTIVE: The objective was to determine the in vitro effect of the somatostatin analog pasireotide (SOM230) on cell proliferation in human corticotroph tumors. DESIGN/METHODS: Expression of somatostatin receptors (SSTR 1-5) was determined by quantitative RT-PCR in 13 human corticotroph tumors and by immunohistochemistry (IHC) in 12 of the 13 tumors. SOM230 effects on cell proliferation and ACTH release were evaluated in vitro using primary cultures of six of the 13 human corticotroph adenomas. RESULTS: In our series, we found expression of SSTR subtypes 1, 2, 4, and 5 in human corticotroph tumors by quantitative RT-PCR. All receptor subtypes were detected by IHC, with SSTR subtype 5 having the highest IHC score in 83% (10 of 12) of the cases. Significant suppression of cell proliferation was observed in all tumors cultured (percent suppression range: 10-70%; P = 0.045-0.001). SOM230 inhibited ACTH secretion in five of the six tumors cultured (percent suppression range: 23-56%; P = 0.042-0.001). CONCLUSION: Corticotroph tumors express multiple SSTR subtypes. SOM230 significantly suppressed cell proliferation and ACTH secretion in primary cultures of human corticotroph tumors. These in vitro results support the hypothesis that SOM230 may have a role in the medical therapy of corticotroph tumors.