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A Angeli

Publications and source records attributed to A Angeli.

At least 37 records · Page 2Linked to original sources
PubMed2003

Diagnosis and complications of Cushing's syndrome: a consensus statement.

In October 2002, a workshop was held in Ancona, Italy, to reach a Consensus on the management of Cushing's syndrome. The workshop was organized by the University of Ancona and sponsored by the Pituitary Society, the European Neuroendocrine Association, and the Italian Society of Endocrinology. Invited international participants included almost 50 leading endocrinologists with specific expertise in the management of Cushing's syndrome. The consensus statement on diagnostic criteria and the diagnosis and treatment of complications of this syndrome reached at the workshop is hereby summarized.

Cardiovascular Diseases↗
PubMed2003

Autocrine down-regulation of glucocorticoid receptors by interleukin-11 in human osteoblast-like cell lines.

It has recently been suggested that interleukin (IL)-11 plays a role in the pathogenesis of glucocorticoid (GC)-induced osteoporosis. IL-11 belongs to the gp130 cytokine family, which includes also IL-6. We have previously investigated GC-IL-6 interplay, showing that GC inhibits IL-6 release and IL-6 up-regulates GC receptor (GR) numbers in the human osteoblast-like cell lines Saos-2 and MG-63, which constitutively have an opposite pattern of expression for GR, IL-11, IL-6, alkaline phosphatase and osteoprotegerin (OPG). The aim of this study was to investigate GC-IL-11 interplay in the same two cell lines. First, cells were incubated with cortisol (0.01-1 microM) for 20 h in the presence and in the absence of a known IL-11 secretagogue (IL-1beta); cell media were assayed for IL-11 by ELISA. Secondly, cells were incubated with IL-11 (0.1-100 ng/ml) or specific anti-IL-11 monoclonal antibody for 20 h, and then assayed for GR by a radioligand binding assay. Similar to IL-6, both constitutive and IL-1beta-inducible IL-11 release were dose-dependently inhibited by cortisol (P<0.01); at variance with IL-6, exogenous IL-11 dose-dependently decreased GR numbers in MG-63 cells (P<0.05), while anti-IL-11 antibody significantly increased GR numbers in both cell lines (P<0.05). IL-11-induced reduction of GR in MG-63 cells was confirmed by Western blot analysis. While exerting opposite effects on GR numbers, neither IL-6 nor IL-11 significantly modified GC-dependent inhibition of OPG release. Our data indicate that even physiological concentrations of cortisol negatively modulate IL-11 secretion and demonstrate, for the first time, an inhibitory effect of the cytokine on GR. Thus, the concept of autocrine-paracrine loops that modulate GC action and involve gp130 cytokines is corroborated. These loops could have clinical relevance for the dynamics of bone loss in patients given GC and having high concentrations of these cytokines in the bone microenvironment.

Antibodies, Monoclonal↗
PubMed2002

Interactions between glucocorticoids and cytokines in the bone microenvironment.

Cytokines belonging to the so-called interleukin-6 (IL-6) or gp130 cytokine family, notably IL-6 and IL-11, are known as pro-resorptive cytokines, in that they promote osteoclastogenesis. Glucocorticoid (GC)-induced osteoporosis is admittedly the most frequent secondary osteoporosis. The pathogenesis still has many unresolved issues. Although the effects of GCs on cytokine production and recognition have been extensively studied, little is known about the effects of cytokines on GC action at the target level. We have focused on the effects of IL-6 and IL-11 on specific binding by type II GC receptors (GRs) in two human osteoblast-like cell lines (Saos-2 and MG-63) that have remarkably different constitutive expression of these cytokines and GRs as well. We have provided evidence that IL-6 upregulates GR binding sites, while IL-11 downregulates these sites, as determined by radioligand binding assay and Scatchard analysis. GR affinity (K(d)) did not change after exposure to both cytokines. A number of experiments were consistent with the view that in human osteoblast-like cells, cytokines of the IL-6 family have autocrine modulatory effects on GRalpha (GRbeta is a variant that does not bind specifically in our method). Complex effects of GCs on the system(s) of proinflammatory/anti-inflammatory cytokines and conversely of these cytokines on GC action could account for the dynamics of bone loss in patients given GCs and conceivably having high concentrations of these cytokines in the bone microenvironment.

Autocrine Communication↗
PubMed2002

Cortical-sparing laparoscopic adrenalectomy in a patient with multiple endocrine neoplasia type IIA.

We describe the case of a patient affected by multiple endocrine neoplasia type IIA with a new diagnosis of an asymptomatic right pheochromocytoma. The patient underwent laparoscopic adrenalectomy with adrenal sparing. The removal of the tumor was successful with preservation of about one third of the adrenal gland. At the time of the last follow-up, the patient is well with partial hypoadrenalism without replacement therapy. The limitations to cortical-sparing adrenalectomy imposed by traditional open surgery (small tumor with peripheral location) can be reconsidered using the laparoscopic approach. Laparoscopic cortical-sparing adrenalectomy should become the gold standard for treatment of bilateral pheochromocytoma. The advantages of this technique are its efficacy and its reduced invasiveness with a low rate of complications either during the operation or in the postoperative period. Moreover, the preservation of a portion of the adrenal cortex may prevent the need for a life-long steroid replacement therapy.

Adrenal Cortex↗
PubMed2001

Inhibitory effect of physiological concentrations of cortisol but not estradiol on interleukin (IL)-6 production by human osteoblast-like cell lines with different constitutive IL-6 expression.

Estrogen deficiency and glucocorticoid excess are two well-known conditions that account for osteoporosis. Interleukin (IL)-6 plays an important role in bone resorption; both estrogens and glucocorticoids are credited with an inhibitory effect on osteoblast production of IL-6. The aim of the study was to investigate whether endogenous hormones, which lead to opposite changes in bone mass, have a common inhibitory effect upon constitutive and inducible IL-6 production by human osteoblast-like cells. We used two human osteosarcoma cell lines (MG-63 and Saos-2) with a different degree of differentiation and constitutive production of IL-6 [2587+/-536 (mean+/-SE) and 3.65+/-0.06 pg/10(6) cells, respectively]. We examined the effects of physiological and supraphysiological concentrations of 17beta-estradiol (E2) and cortisol on basal and IL-1beta-induced IL-6 release in the medium. In all experimental conditions, cellular estrogen receptors (ERs) and glucocorticoid receptors (GRs) were measured by binding assay. Both MG-63 and Saos-2 cell lines had measurable GRs (106 300+/-24 996 and 18 100+/-3215 binding sites/cell, respectively) and ERs (2197+/-377 and 1261+/-66.5 binding sites/cell, respectively). In MG-63 cells, cortisol treatment for 20 h decreased both basal and IL-1beta-induced IL-6 release in a dose-dependent manner; in Saos-2 cells the same effect was apparent for IL-1beta-induced release. Mifepristone (RU-486) did function as partial agonist and antagonist of cortisol. At variance with cortisol, E2 did not exert any effect on IL-6 secretion. Treatment with 1,25(OH)2D3 increased by 100-200% ER concentrations, but did not change ineffectiveness of E2 in modifying IL-6 production; furthermore, when E2 was combined with cortisol, there was no additive effect on cortisol-induced inhibition. The dissociation between glucocorticoid and estrogen effects observed in these human cell lines is a sufficiently robust phenomenon to raise questions about the pathogenetic role of IL-6 in osteoporosis associated with estrogen deficiency. Conversely inhibition of osteoblast production of IL-6 may offer an explanation why bone resorption is not the dominant factor in the pathogenesis of glucocorticoid-induced osteoporosis.

Binding Sites↗
PubMed2001

Effects of the somatostatin analog lanreotide on the circulating levels of chromogranin-A, prostate-specific antigen, and insulin-like growth factor-1 in advanced prostate cancer patients.

BACKGROUND: The concept that neuroendocrine cells detected within prostate adenocarcinoma produce paracrine factors, that may exert a proliferative effect on exocrine prostate tumor cells, provides a rationale for the use of somatostatin analogs with the aim to counteract or delay the tumor progression. This study was designed to provide preliminary information on the effect of the administration of a long-acting somatostatin analog, lanreotide, on plasma levels of chromogranin A (CgA). Secondary aims were the evaluation of changes in circulating prostate-specific antigen (PSA) and insulin-like growth factor-1 (IGF-1). METHODS: Lanreotide (Ipstyl 30 mg; Ipsen, Milan, Italy) was administered intramuscularly every 14 days for 2 months to nine heavily pretreated prostate cancer patients with hormone refractory disease. All patients had, at baseline conditions, CgA values above the normal range. Androgen deprivation was maintained during the study period, while other concomitant antineoplastic treatments were not allowed. Serum PSA levels and plasma CgA and IGF-1 values were measured every week. RESULTS: Lanreotide treatment was very well tolerated and no patient experienced major toxicity. Plasma CgA values at baseline: mean 109 U/liter, standard deviation +/- 85 decreased significantly after treatment as follows: 42 U/liter, +/- 17.8; 27.2 U/liter +/- 13.6; 31.4 U/liter, +/- 17.8 and 27.6 U/liter, +/- 17.0; after 7, 14, 21, and 28 days, respectively (P < 0.01, Friedman ANOVA). Serum PSA did not change. Baseline IGF-1 was found to be above the detection limit in four cases, all of them showing a decrease after lanreotide. CONCLUSIONS: Lanreotide administration to prostate cancer patients induces a decrease in plasma CgA and IGF-1 levels, without any influence on serum PSA values. Prostate 47:205-211, 2001.

Adenocarcinoma↗
PubMed2001

RET proto-oncogene mutation in a mixed medullary-follicular thyroid carcinoma.

A case of a patient with an uncommon thyroid carcinoma, showing histological and immunohistochemical features of both follicular and parafollicular cells is described. Somatic point mutation (ATG to ACG heterozygotic mutation at codon 918) of the RET proto-oncogene was detected in tumor tissue, as confirmed by immunohistochemical expression of RET oncoprotein. Our findings suggest that constitutive RET proto-oncogene activation may be involved in the development of mixed medullary-follicular thyroid carcinoma.

Adenocarcinoma, Follicular↗
PubMed2001

Autocrine up-regulation of glucocorticoid receptors by interleukin-6 in human osteoblast-like cells.

Interleukin (IL)-6 is a bone-resorbing cytokine that acts primarily on osteoclast progenitors to stimulate both proliferation and differentiation. Glucocorticoids (GC) down-regulate IL-6 synthesis in different cell types, including osteoblasts. Given the fact that bone remodeling is a tightly controlled process, it is reasonable to think of auto-regulatory mechanisms in the bone microenvironment able to prevent excess IL-6 production. We have studied two human osteosarcoma cell lines (Saos-2 and MG-63) with different degrees of differentiation and different constitutive IL-6 production (3.4 +/- 0.2 (mean +/- SE) and 2,898 +/- 401 pg/10(6) cells, respectively). We measured the expression of glucocorticoid receptor (GR) in terms of specific binding sites after exposure of cells to different amounts of IL-6. Incubation for 20 hours with IL-6 at increasing concentrations up to 2,000 pg/ml yielded significant increase of GR binding sites in both cell lines. IL-6 was also able to revert the inhibitory effect of dexamethasone (1 microM) on GR in both cell lines. In MG-63 cells, that express higher concentrations of GR, IL-6 deprivation via a specific anti-IL-6 antibody (100 ng/ml) significantly decreased GR, as it was noticed, although to a lesser degree, using a specific anti-IL-6 receptor antibody. In Saos-2, cells that express lower concentrations of GR, a 40-hour treatment with human IL-1beta (10 ng/ml) significantly increased both IL-6 production and GR. This latter effect was completely abolished by co-treating the cells with the anti-IL-6 antibody. Our data are consistent with an autocrine up-regulation of GR expression by IL-6 in human osteoblast-like cells. This phenomenon, which is also relevant to paracrine cell-to-cell communication, subserves a feedback loop in the bone microenvironment that restrains excess inducible IL-6 production. In patients having high levels of IL-6 and given GCs, it could offer an additional explanation for the biphasic pattern of bone loss in the course of therapy.

Antibodies, Monoclonal↗
PubMed2001

Immunohistochemical assessment of Ki-67 in the differential diagnosis of adrenocortical tumors.

OBJECTIVES: To evaluate the utility of Ki-67 immunohistochemical analysis in the differential diagnosis between benign and malignant adrenocortical neoplasms. METHODS: Tissue specimens were obtained from 37 patients referred to our institute from 1990 to 1999. The indications for adrenalectomy were adrenal-dependent Cushing syndrome (n = 9), hyperandrogenism (n = 1), mineralocorticoid excess (n = 8), and nonfunctioning adrenal masses (n = 19). The histologic diagnosis was cortical adenoma in 26 of 37 patients and cortical carcinoma in the remainder. Normal adrenal glands were obtained from subjects who underwent radical nephrectomy because of initial renal carcinoma. Immunohistochemical analysis was performed using the monoclonal antibody anti-Ki-67 (clone MIB-1). The Ki-67 labeling index was expressed as the number of positive cells per 1000 cells.Results. The average Ki-67 expression was 2.0 per thousand +/- 1.2 per thousand (SD) in normal adrenal glands, 11.3 per thousand +/- 16.0 per thousand in adenomas, and 185.8 per thousand +/- 60.3 per thousand in carcinomas (P <0.0001). A threshold value of the Ki-67 labeling index between 70 per thousand and 90 per thousand reliably separated adenoma from carcinoma. A significant inverse correlation was found between Ki-67 expression and overall survival in patients with adrenal carcinoma (r = -0.74, P = 0.009). CONCLUSIONS: Immunohistochemical assessment of the nuclear antigen Ki-67 can be useful in the differential diagnosis between adrenocortical adenoma and carcinoma. High levels of Ki-67 seem to indicate patients with adrenocortical cancer with a worse prognosis.

Adenoma↗
PubMed2001

Relationship between blood pressure and glucose tolerance in acromegaly.

BACKGROUND: Hypertension represents a well-known risk factor for cardiovascular diseases. The pathogenesis of hypertension in acromegaly is commonly viewed as multifactorial, but the possible influence of metabolic disorders on blood pressure (BP) in affected patients is largely unknown. OBJECTIVE: The aim of the present study was to evaluate the impact of glucose metabolism abnormalities on BP values in a series of patients with active acromegaly. DESIGN: An open multicentre prospective study. PATIENTS: Sixty-eight patients with active disease, aged 47.5 +/- 11.7 years, have been studied. Thirty-nine had normal glucose tolerance (NGT), 16 impaired glucose tolerance (IGT) and 13 suffered from diabetes mellitus (DM). MEASUREMENTS: Mean clinical BP values were calculated as the mean of BP values obtained by sphygmomanometric measurement in three separate occasions and mean 24-h, diurnal and nocturnal systolic (SBP) and diastolic (DBP) values were obtained by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS: Patient's age and the degree of glucose tolerance abnormalities were found to significantly and independently influence BP values. All clinical and ABPM SBP and DBP values significantly increased with age by linear regression (P < 0.02 for all BP values, 0.30 < or = R < or = 0.43), and the independent influence of this parameter on BP values was confirmed by mutivariate analysis. Similarly, the independent influence of glucose tolerance abnormalities on BP values was confirmed when introducing age as a covariable in a multivariate analysis, and patients with DM presented significantly higher clinical SBP and 24-h, diurnal and nocturnal SBP and DBP than patients with NGT (P < 0.02 for clinical SBP, P < 0.015 for all ABPM values, respectively). In addition, patients with DM showed significantly higher 24-h, diurnal and nocturnal DBP than those with IGT (P < 0.05 in all cases). In contrast, no significant difference was found between NGT and IGT patients. No significant influence of disease duration, BMI, GH, IGF-I, or fasting and 2-h post glucose load insulinaemia on BP values was observed. CONCLUSIONS: Abnormalities of glucose metabolism significantly contribute to increase systolic blood pressure and especially diastolic blood pressure in acromegalic patients. Careful control of blood pressure and of risk factors for developing systemic hypertension, with special reference to glucose tolerance, is mandatory to decrease cardiovascular morbidity and mortality in such patients.

Acromegaly↗
PubMed2001

The limited value of the desmopressin test in the diagnostic approach to Cushing's syndrome.

OBJECTIVE: The desmopressin test is generally regarded as an alternative to the CRH test but it is unclear whether desmopressin is as effective as CRH in the differential diagnosis of ACTH-dependent Cushing's syndrome. However, a precise assessment of the operating characteristics of the desmopressin test in comparison with the CRH test has not been reported. The aim of the present study was to make a comparative evaluation of desmopressin and CRH tests in a consecutive cohort of patients with ACTH-dependent Cushing's syndrome and in a group of healthy subjects. DESIGN AND SUBJECTS: We studied 34 patients with Cushing's disease (CD) and nine patients with ectopic ACTH syndrome (EAS). The control group included 30 healthy subjects. Estimates of sensitivity and specificity were determined for a value of ACTH percent increment (Delta%) > 35% and for a Delta % > 50%, following either desmopressin or CRH, to differentiate CD from EAS. The sensitivity and specificity of a composite rule requiring an ACTH net increment (Delta) > 4.5 pmol/l at both values of Delta % was also calculated. When evaluating cortisol responses, the criteria were Delta % > 20% and Delta > 193 nmol/l. Moreover, to allow comparison of individual end points of the desmopressin and CRH tests at multiple levels of Delta % or Delta either for ACTH or cortisol without the bias of predetermined criteria, univariate curves of the receiver operating characteristics (ROC) were constructed by plotting the sensitivity against 1 - specificity at each level. RESULTS: In the patients with CD, the frequency of ACTH response was of 90% after both tests while the figures for cortisol were 73% after CRH and 77% after desmopressin, respectively. In the 15 patients who underwent both tests the magnitude of ACTH and cortisol responses induced by the 2 stimuli were fully comparable. In the patients with EAS a (false) positive ACTH response was found in 2/9 cases (22%) after the CRH test and in 2/5 patients (40%) after the desmopressin test. In the healthy subjects the CRH test was performed in 25 cases and the desmopressin test in 15 cases. The frequency of ACTH response was 52% following CRH and 13% following desmopressin. In the 10 healthy subjects who underwent both tests the ACTH response was significantly greater after CRH than desmopressin. The area under the ROC curve for the ACTH Delta % was significantly different than that occurring by chance following CRH but not desmopressin. The point on the ROC curve closest to 1 corresponded to an ACTH Delta % of 47% (sensitivity 87% and specificity 89%). However, a criterion of 100 % specificity would require an increase in the threshold for the ACTH Delta % to 259%. ROC analysis validated also the use of the ACTH Delta as a method to assess the response to CRH, but not after desmopressin. However, the diagnostic performance of this parameter was reduced in comparison to that of the ACTH Delta %, since the best cut-off for the Delta (6.2 pmol/l) had inferior specificity (79%). The operating characteristics of CRH and desmopressin were worse when considering cortisol responses. CONCLUSIONS: The present data suggest that the CRH test is more reliable than the desmopressin test in determining the aetiology of Cushing's syndrome. The desmopressin test resulted in a high frequency of false positive results in patients with ectopic ACTH secondary to carcinoid tumours. This finding may be due to the capability of these tumours to express the V3 vasopressin receptor through which desmopressin acts. However, the clinical endocrinologist may be confronted with some disturbing cases which are misdiagnosed because it is almost impossible to set a diagnostic criterion providing complete specificity in the differentiation of (occult) ectopic Cushing's syndrome using either CRH or desmopressin tests.

ACTH Syndrome, Ectopic↗
PubMed2001

Potential clinical value of circulating chromogranin A in patients with prostate carcinoma.

BACKGROUND: Neuroendocrine (NE) differentiation of prostate adenocarcinoma has received increasing attention in recent years as a result of possible implications for prognosis and therapy. The presence of NE tumor subpopulation can be gauged non invasively by measuring circulating levels of secretory products, primarily chromogranin A (CgA). METHODS: This article provides a review on published papers evaluating circulating CgA in prostate cancer patients. RESULTS: Circulating CgA levels were found to be higher in prostate cancer patients than in patients with benign or pre-malignant prostatic diseases. In patients with malignancy, they correlated either to the stage of disease or to the condition of hormone refractoriness. CgA levels did not correlate with serum prostate specific antigen (PSA) and were supranormal in the majority of advanced patients with PSA within normality. In hormone refractory cases, elevated CgA was a significant predictor of poor prognosis, independently from serum PSA. CgA values were not substantially affected by either endocrine therapy or chemotherapy. They were found to increase during androgen deprivation in some cases and this trend preceded that of PSA. The administration of a somatostatin analog in hormone refractory cases was able to reduce plasma CgA values consistently. CONCLUSIONS: Present data suggest a potential role of circulating CgA in the management of prostate cancer patients. CgA determination may be useful diagnostically and prognostically and could offer complementary information with respect to PSA. Serial evaluation of circulating CgA could provide information on changes in the NE phenotype expression as a consequence of tumor progression and/or treatment administration.

Androgen Antagonists↗
PubMed2001

Relationship between neuroendocrine features and prognostic parameters in human prostate adenocarcinoma.

PURPOSE: The biological behaviour of prostate cancer is highly variable and prediction by the commonly employed prognostic parameters is not sufficient. The concept of neuroendocrine (NE) differentiation in prostate adenocarcinoma has recently received increasing attention due to possible implications for prognosis and therapy. MATERIALS AND METHODS: Core needle biopsies from 142 newly diagnosed patients were immunohistochemically examined for the coexistence of NE differentiation using an antibody against chromogranin A (CgA). Circulating CgA was available in 106 of these patients. RESULTS: NE differentiation was found in 64 (45.1%) tumors. Among them 29 (20.4%) had CgA positive cells scattered or focally distributed in less than 5% per mm3 of tumor tissues, 26 (18.3%) between 5% and 10% and 9 (6.4%) more than 10%, respectively. There was a significant correlation between the extent of NE features and either Gleason score (P < 0.01) or stage of disease. Circulating CgA but not PSA correlated with immunohistochemical CgA (P < 0.03) particularly in metastatic cases. CONCLUSIONS: These data support the concept that NE differentiation in human prostate cancer has a negative prognostic significance. Circulating CgA levels reflect immunohistochemical findings.

Adenocarcinoma↗
PubMed2001

Circulating chromogranin A in the assessment of patients with neuroendocrine tumours. A single institution experience.

BACKGROUND: Chromogranin A (CgA) is a secretory protein present in dense-core vesicles of neuroendocrine (NE) cells. Its ubiquitous presence in NE tissues makes it a suitable circulating marker of neoplasms of NE origin. PATIENTS AND METHODS: Plasma CgA was determined in 178 patients with NE tumors and in 36 patients with non-endocrine malignancies. Circulating CgA was also serially evaluated in 39 NE cancer patients with advanced disease submitted to systemic therapy and in 14 patients with no evidence of disease (NED). RESULTS: Supranormal CgA values were found in 81% of patients with advanced NE tumors and in only 91% of NED cases. Plasma CgA in patients with well differentiated NE tumors, such as carcinoids, carcinoma of gastrointestinal tract, pheocromocytoma, pancreatic NE carcinoma (either functioning or not functioning), medullary thyroid carcinoma and NE tumors from various primary sites, was higher and more frequently elevated than in patients with small-cell lung cancer (P < 0.001). Plasma CgA did not discriminate patients with NE from those with non NE neoplasms since it was found elevated in 44% of the latter cases. Plasma CgA pattern correlated with the disease response in patients submitted to cytotoxic treatment and with changes in clinical symptomathology in patients receiving somatostatin analogs. CONCLUSIONS: Our data confirm that CgA is the best circulating neuroendocrine marker available up to now available for the management of differentiated neuroendocrine malignancies irrespective of tumor location and functional status. CgA plasma levels could also identify the coexistence of neuroendocrine differentiation in the context of non-endocrine malignancies. Circulating CgA seems to be less useful in undifferentiated tumors such as small-cell lung cancer.

Adolescent↗
PubMed2001

Ectopic ACTH syndrome: molecular bases and clinical heterogeneity.

There are roughly two types of ectopic ACTH syndrome (EAS). one associated with overt malignancies and one with occult neoplasms. The prototype of the first condition is Cushing's syndrome sustained by small-cell lung cancer (SCLC), while bronchial carcinoid tumors are the most common occult sources of ACTH. Patients with EAS and SCLC may have an atypical presentation with muscle wasting and weight loss that are more frequently observed than the classic cushingoid features. These patients have a poor prognosis because SCLC associated with the EAS is more resistant to chemotherapy and the severe hypercortisolism is responsible for a high rate of life-threatening complications during treatment. Conversely, the clinical and biochemical features of the EAS associated with carcinoid may overlap those seen in pituitary-dependent Cushing's syndrome. An extensive radiological and hormonal work-up is necessary to detect the extrapituitary source of ACTH. However, the differentiation between the pituitary, or eutopic, from the non-pituitary, or ectopic, source of ACTH secretion may be extremely difficult in some cases despite the wide diagnostic armamentarium available. Molecular biology studies have demonstrated that the carcinoid cells achieve a process of corticotroph differentiation being able to express the proopiomelanocortin (POMC) gene and to process POMC correctly to release large amounts of intact ACTH. Conversely, SCLC processes POMC in an aberrant way releasing high concentrations of ACTH precursors and less intact ACTH in the circulation.

ACTH Syndrome, Ectopic↗