Ectopic (inappropriate) hormone production by tumors: mechanisms involved and the biological and clinical implications

Mammalian tumor-like organs. 2. Mammalian adipose has many tumor features and obesity is a tumor-like process

BACKGROUND

In previous publications, the author developed the theory of carcino-evo-devo, which predicts that evolutionarily novel organs should recapitulate some features of tumors in their development.

MAIN TEXT

Mammalian adipose is currently recognized as a multi-depot metabolic and endocrine organ consisting of several adipose tissues. Although lipid-storing cells and proteins are ancient, the adipose organ as a whole is evolutionarily novel to mammals. The adipose expansion has remarkable similarities with the growth of solid tumors. These similarities are the following: (1) The capability to unlimited expansion; (2) Reversible plasticity; (3) Induction of angiogenesis; (4) Chronic inflammation; (5) Remodeling and disfunction; (6) Systemic influence on the organism; (7) Hormone production; (8) Production of miRNAs that influence other tissues; (9) Immunosuppression; (10) DNA damage and resistance to apoptosis; (11) Destructive infiltration in other organs and tissues. These similarities include the majority of "hallmarks of cancer". In addition, lipomas are the most frequent soft tissue tumors, and similar drugs may be used for the treatment of obesity and cancer by preventing infiltration. This raises the possibility that obesity, at least in part, may represent an oncological problem. The existing similarities between adipose and tumors suggest the possible evolutionary origin of mammalian adipose from some ancestral benign mesenchymal hereditary tumors. Indeed, using a transgenic inducible zebrafish tumor model, we described many genes, which originated in fish and were expressed in fish tumors. Their human orthologs LEP, NOTCH1, SPRY1, PPARG, ID2, and CIDEA acquired functions connected with the adipose organ. They are also involved in tumor development in humans.

CONCLUSION

If the hypothesis of the evolutionary origin of the adipose organ from the ancestral hereditary tumor is correct, it may open new opportunities to resolve the oncological problem and the problem of the obesity epidemic. New interventions targeting LEP, NOTCH1, SPRY1, PPARG, ID2, and CIDEA gene network, in addition to what already is going on, can be designed for treatment and prevention of both obesity and tumors.

Molecular challenges of neuroendocrine tumors

Neuroendocrine tumors (NETs) are a very heterogeneous group that are thought to originate from the cells of the endocrine and nervous systems. These tumors develop in a number of organs, predominantly in the gastrointestinal and pulmonary systems. Clinical detection and diagnosis are reliable at the late stages when metastatic spread has occurred. However, traditional conventional therapies such as radiation and chemotherapy are not effective. In the majority of cases even surgical resection at that stage is unlikely to produce promising reusults. NETs present a serious clinical challenge, as the survival rates remain low, and as these rare tumors are very difficult to study, novel approaches and therapies are required. This review will highlight the important points of accumulated knowledge covering the molecular aspects of the role of neuroendocrine cells, hormonal peptides, the reasons for ectopic hormone production in NET, neuropeptides and epigenetic regulation as well as the other challenging questions that require further understanding.

Acromegaly in a patient with a pulmonary neuroendocrine tumor: case report and review of current literature

Background

Pulmonary neuroendocrine tumors (NET) form a heterogeneous group of rare diseases. In these tumors, paraneoplastic syndromes have been described to drive the course of the disease, among them acromegaly induced by paraneoplastic secretion of growth hormone-releasing hormone (GHRH).

Case presentation

We report the case of a 43 years old patient initially diagnosed with acromegaly accompanied by weight gain and acral enlargement. Subsequently, further diagnostic work-up identified a solitary pulmonary neuroendocrine tumor (NET). Laboratory tests revealed markedly increased growth hormone (GH) and insulin-like growth factor 1 (IGF-1) without GHRH elevation in the absence of pituitary pathologies confirming the paraneoplastic origin of clinical presentation with acromegaly. Curative surgery was performed leading to normalization of the elevated hormone levels and improvement of the clinical symptoms. Immunohistochemically, a typical carcinoid (TC) was seen with low proliferation index and abundant IGF-1 expression.

Conclusions

The association of acromegaly and pulmonary NET has only rarely been reported. We present an individual case of paraneoplastic GH- and IGF-1 secretion in a patient with pulmonary NET. Based on their rarity, the knowledge of paraneoplastic syndromes occurring in patients with pulmonary NET such as acromegaly due to paraneoplastic GH- and IGF-1 secretion is mandatory to adequately diagnose and treat these patients.

Cushing's syndrome due to an ACTH-producing primary ovarian carcinoma

Although Cushing's syndrome has been described in association with various neuroendocrine tumors producing ectopic adrenocorticotropin (ACTH), primary ovarian carcinoma rarely causes this syndrome. We hereby report the case of a 61-year-old woman presented with abdominal distension, facial swelling and skin pigmentation. Clinical and diagnostic evaluation revealed a right ovarian tumor with hypercortisolemia, high plasma ACTH, extremely high plasma ACTH precursors and lack of dexamethasone suppression. Removal of the tumor led to normalization of ACTH, ACTH precursors and cortisol levels. In addition, hypokalemia, hyperglycemia and elevated serum CA 125 were noted, which were also normalized after resection of the tumor. Histopathological examination indicated a primary ovarian carcinoma with a mixed pattern of differentiation. Immunohistochemistry showed immunoreactivity for chromogranin A, synaptophysin and ACTH. Hence, the diagnosis of Cushing's syndrome arising from an ovarian carcinoma secreting ectopic ACTH was made. The case was managed successfully, with subsequent good recovery and no evidence of recurrence at 4 years of follow-up.

Establishment and characterization of a novel cell line derived from a human small cell lung carcinoma that secretes parathyroid hormone, parathyroid hormone-related protein, and pro-opiomelanocortin

There are few case reports describing small cell lung carcinoma (SCLC), which secrete parathyroid hormone (PTH)-related protein (PTHrP) and result in hypercalcemia. We have established a novel cell line, derived from a 37-year-old woman with SCLC, which produced PTH, PTH-rP, and a part of proopiomelanocortin (POMC), and led to hypercalcemia. The cell line, named SS-1, was grown as floating cell clusters in DMEM/F12 medium supplemented with 10% fetal bovine serum and had a population doubling time of 72 h. The modal chromosome number was 47 (88%); marker chromosomes were not observed. The SS-1 cell line secreted not only PTHrP but also PTH, and both were decreased by CaCl(2) administration. Decreasing the concentration of Ca(++) in the growth medium stimulated the secretion of both PTHrP and PTH. The cell line had calcium sensing receptor (Cas-R). Since PTHrP and PTH secretion from the SS-1 cells was related to Ca(++) concentration in the growth medium, the cell line might be useful for the study of PTH-rP and PTH regulation as well as for SCLC analysis. In addition, the cells secreted N terminal POMC, the precursor of adrenocorticotropic hormone, in response to stimulation with corticotropin releasing hormone. In summary, we established a novel cell line, SS-1 from SCLC, which produced PTHrP, PTH and N terminal POMC.

p21-activated kinase 3 is overexpressed in thymic neuroendocrine tumors (carcinoids) with ectopic ACTH syndrome and participates in cell migration

Thymic carcinoid is an important component of the tumor spectrum causing Ectopic ACTH Syndrome (EAS) and usually carries a poor prognosis. Efforts have been focused on exploring the mechanism of the excessive ACTH production in non-pituitary tumors, whereas few studies have reported the molecular events underlying the tumor progression. In this study, seven patients with ACTH producing thymic carcinoids were enrolled. Of note is that five of them showed either lymph node metastasis, local invasion or distant metastasis. By using cDNA profiling approach, we evaluated the expression of cell adhesion pathway genes and found a remarkable overexpression of p21-activated kinase 3 (PAK3) in all thymic carcinoids which was further confirmed at both transcriptional and translational level. RAC1, an upstream activator of PAK3, was also overexpressed in thymic carcinoids. Overexpression of PAK3 in NIH3T3 cell enhanced cell migration and invasion. Importantly, we observed c-Jun NH(2)-terminal kinase (JNK) was activated in PAK3 transfected cells, and inhibition of JNK activity by SP600125, a JNK pathway inhibitor, abolished PAK3 mediated cell migration. Activation of JNK pathway was also detected in thymic carcinoid with high level of PAK3 expression. Our findings suggested a potential role of PAK3 in the progression of ACTH-producing thymic carcinoid.

An ACTH-secreting pituitary adenoma within the sphenoid sinus

A 68-year-old woman developed Cushingoid features three months prior to admission. She was found to have a markedly elevated plasma ACTH-cortisol level. Magnetic resonance imaging (MRI) revealed a mass in the left sphenoidal sinus, which had become enlarged to a point where it could not be removed by transsphenoidal surgery. We decided to proceed with radiation therapy to shrink the tumor. However, it was ineffective. Despite a reduction in serum cortisol levels using metyrapone, she died of septic shock. We describe a rare case of an ACTH-secreting pituitary adenoma within the sphenoid sinus.

Paraneoplastic syndromes in patients with nasopharyngeal cancer

Paraneoplastic syndromes (PNS) represent the clinical manifestation of the remote and indirect effects produced by tumor metabolites or other products. Paraneoplastic effects are not directly mediated by tumor invasion of normal tissue, or by the disruption of normal function of the involved organ, or by distant metastases. More than 260 cases of nasopharyngeal carcinoma (NPC) associated with PNS have been reported in the literature. These syndromes can be divided into six main groups: cutaneous or dermatologic, endocrine, hematologic, osteoarticular or rheumatologic, neurologic, and ocular. The most common dermatologic manifestation is dermatomyositis, while the syndrome of inappropriate secretion of antidiuretic hormone and occasionally Cushing's syndrome due to ectopic ACTH production are the endocrinologic manifestations. Tumor fever and leukemoid reaction, osteoarticular or rheumatic syndromes, including clubbing of the fingers and toes, sensory neuropathy and demyelinating motor polyneuropathy, and rarely optic neuritis represent the most prominent examples of the other groups of syndromes. PNS may occur before the NPC is manifest, or while it is in an occult stage, and thus the possibility of NPC should be considered in patients with these various disorders. While some PNS will respond to direct treatment, most often the PNS subsides in parallel to response of the NPC, and thus may be useful for monitoring tumor response or recurrence.

Insulinoma and gastrinoma syndromes from a single intrapancreatic neuroendocrine tumor

CONTEXT

The insulinoma syndrome is marked by fasting hypoglycemia and inappropriate elevations of insulin. The gastrinoma syndrome is characterized by hypergastrinemia, ulcer disease, and/or diarrhea. Rarely, insulinoma and gastrinoma coexist in the same patient simultaneously.

OBJECTIVE

Our objective was to determine the cause of a patient's hypoglycemic episodes and peptic ulcer disease.

DESIGN AND SETTING

This is a clinical case report from the Clinical Research Center of the National Institutes of Health.

PATIENT AND INTERVENTION

One patient with hypoglycemic episodes and peptic ulcer disease had a surgical resection of neuroendocrine tumor.

RESULTS

The patient was found to have a single tumor cosecreting both insulin and gastrin. Resection of this single tumor was curative.

CONCLUSIONS

A single pancreatic neuroendocrine tumor may lead to the expression of both the hyperinsulinemic and hypergastrinemic syndromes.

Ectopic ACTH syndrome

Ectopic adrenocorticotropic secretion (EAS) is responsible for 12-17% of cases of Cushing's syndrome (CS) and covers a range of tumours, from undetectable benign lesions to widespread metastases. The syndrome is often associated with severe hypercortisolaemia, which aggravates the underlying condition. EAS requires a complete workup that includes the establishment of endogenous CS, diagnosis of adrenocorticotropic hormone (ACTH) dependency, localization of the source of ACTH secretion and rapid biochemical control of hypercortisolaemia. Dynamic endocrine tests should include inferior petrosal sinus sampling with CRH stimulation. Localization studies depend on the availability of reliable high-resolution cross-sectional imaging. This systematic review of the largest published series of patients with EAS (over 380 patients) reveals the common trends in the prevalence and management of this syndrome. The concept of 'occult' EAS has been revisited and the terms 'overt' and 'covert' EAS introduced. In addition to small cell lung carcinoma, the most common causes of ectopic EAS are bronchial carcinoids, thymic tumours, islet cell tumour of the pancreas, medullary thyroid carcinomas, and phaeochromocytomas. Their prevalence and the best localization modalities are presented. Medical and surgical management is discussed on the basis of the extensive experience of major referral centres.

Paraneoplastic Syndromes: Elements of Interest for the Urologist

A paraneoplastic syndrome is a clinical condition in a patient affected by tumor which occurs distally from the primary neoplasia or its metastases, and is assessed via the humoral mediators. The uncommon secretion of peptide hormones is the most frequent cause of paraneoplastic syndromes. Although the symptoms are strongly varied, paraneoplastic endocrine syndromes are characterized by several functional features that differentiate them from the endocrine glands hyper-function related disorders. Based on the field's literature, the article presents the pathogenetic mechanisms, the laboratory and imaging features, and the essential therapeutic measures for humoral hypercalcemia of malignancy, hypercortisolism from ectopic ACTH/CRH production and water intoxication syndrome due to inadequate ADH secretion. Moreover, neuroendocrine differentiation in some urogenital cancers (prostate, bladder, kidney etc.), occurring as pure endocrine malignancy or as focal lesion, can develop a paraneoplastic carcinoid-like syndrome. On the other hand, some patients with urogenital tumors have increased serum levels of IGF-2 resulting in paraneoplastic hypoglycemia.

An ectopic adrenocorticotropic hormone syndrome caused by a sacrococcygeal chordoma: report of a case with a slow progression

OBJECTIVE

To report the first case of an ectopic adrenocorticotropic hormone (ACTH) syndrome caused by a sacrococcygeal chordoma.

METHODS

We present a case report with clinical, laboratory, and histologic details.

RESULTS

A 76-year-old man was admitted to the hospital because of urinary obstruction. Five years previously, a urethral mass had been detected, and transurethral prostatectomy had been performed. Annual computed tomographic (CT) scans showed no change in size of the mass. In 1995, skin hyperpigmentation, central obesity, and bilateral edema were noted. The patient was admitted to the hospital in July 1996. A CT scan of the abdomen revealed a large mass close to the sacrum and compressing the bladder and rectum. Cortisol measurements (AM and PM) were 309 and 271 ng/mL, respectively. The plasma ACTH concentration was extremely elevated (3,125 pg/mL). Although resection of the mass was attempted, complete resection was not possible because the tumor had infiltrated the sacrum. Plasma cortisol concentrations in samples obtained 7 and 8 days postoperatively were normal. Plasma ACTH was substantially decreased (180 pg/mL) but remained above normal. The histologic features of the tumor were compatible with a chordoma. Neoplastic cells stained positively for ACTH.

CONCLUSION

This report describes the first case of an ectopic ACTH syndrome caused by a sacrococcygeal chordoma. A slow progression of symptoms in an ectopic ACTH syndrome had been described only for carcinoid tumors. These data add a new entry to the list of neoplasms capable of causing this syndrome.

Neuron-specific enolase is an effective tumour marker in non-small cell lung cancer (NSCLC)

BACKGROUND

Neuron-specific enolase (NSE) is a well known marker of small cell lung cancer. The present study was designed to assess the clinical value of NSE in non-small cell lung cancer (NSCLC), as compared to that of carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA).

METHODS

The study comprised 448 new consecutive NSCLC patients seen from 1996 to 2001. A set of 30 anthropometric, clinical, physical, laboratory, radiological, and pathological variables was prospectively recorded for all patients. Patients were carefully followed-up, and their subsequent clinical course recorded.

RESULTS

Increased values of NSE were present in 32% of the patients. Bivariate analyses showed that NSE, TPA and CEA were significantly correlated with each other, lactate dehydrogenase, tumour diameter, and disease extent. Univariate analyses showed that patients with elevated concentration of both NSE and TPA had significantly shorter survivals than patients with low values (30 [95% CI: 25-35] vs. 61 weeks [46-76], and 30 [CI: 24-36] vs. 59 weeks [40-79], respectively, P=0.0000). The Cox proportional hazards model including all the 22 variables significant in univariate analysis selected, in decreasing order of significance, the following variables: (1) N factor; (2) main treatment; (3) ECOG PS; (4) CNS metastasis; (5) age; (6) tumour cavitation; (7) NSE; (8) T factor; and (9) adrenal gland metastasis.

CONCLUSIONS

This data indicates that serum assay of NSE is a useful marker also in NSCLC and a significant predictor of survival, independently of the other prognostic factors.

Endocrine paraneoplastic syndromes in lung cancer

Lung tumors are capable of synthesizing and secreting peptide proteins (hormones) that lead to a variety of endocrine paraneoplastic syndromes. Knowledge about the clinical manifestations, pathophysiology, and treatment of these syndromes has evolved over time. This article provides an up-to-date overview of this knowledge.

Ectopic pro-opiomelanocortin syndrome

Ectopic POMC syndrome remains one of the most challenging differential diagnoses in endocrinology. Recent progress in the understanding of the tissue specific regulation of POMC gene expression and new insights into the processing of the POMC peptide in nonpituitary tissues has helped elucidate some of the molecular events leading to ectopic expression and secretion of POMC peptides. Corticotropin and other POMC-derived peptides have diverse effects on adrenal steroidogenesis, growth, and extra-adrenal tissues. Differences in POMC gene regulation in the corticotrope versus ectopic POMC-producing tumors provides a scientific framework for the clinical distinction between eutopic and ectopic Cushing's syndrome. In an attempt to revisit recent basic and clinical advances in the diagnosis of ectopic POMC syndrome the authors undertook an extensive literature review of 530 cases in 197 published papers and provided a molecular biologic, demographic and diagnostic update. According to this review, the four most common causes of ectopic POMC syndrome are the small cell carcinoma of the lung (27%), bronchial carcinoids (21%), islet cell tumor of the pancreas (16%), and thymic carcinoids (10%). Although the clinical features of patients with ectopic POMC syndrome are similar to those with Cushing's disease, subgroup analysis reveals a broad spectrum of severity and progression of signs and symptoms of hypercortisolism. The endocrine workup of a patient with suspected ectopic POMC syndrome includes the establishment of pathologic hypercortisolism, diagnosis of corticotropin dependency, and the differential diagnosis of corticotropin-dependent Cushing's syndrome. The use of a variety of baseline endocrine values, dynamic endocrine testing, and invasive procedures leads to the correct diagnosis in the majority of patients with ectopic POMC syndrome. Diagnostic imaging, including conventional radiological techniques and somatostatin receptor scintigraphy, aids in the correct localization and eventual treatment of ectopic POMC production.

Analysis of the human proopiomelanocortin gene promoter in a small cell lung carcinoma cell line reveals an unusual role for E2F transcription factors

The small cell lung carcinoma (SCLC) cell line DMS-79 has been used as a model for studying the molecular mechanism underlying the ectopic ACTH syndrome. We previously showed that two domains of the human Proopiomelanocortin (POMC) gene promoter were specifically active in DMS-79 cells. The present study focuses on the more distal one, Domain IV (-376/-417). DNaseI footprinting experiments identified a single binding site for DMS-79 cell proteins in this domain. Gel-shift and sequence analysis indicated that E2F proteins might bind this site. Indeed, proteins from DMS-79 cells which bind this site (i) have in vitro DNA binding properties indistinguishable from those of E2F proteins (ii) form, like E2F proteins, multiprotein complexes which can be dissociated by sodium deoxycholate and (iii) are recognized by antibodies directed against E2F proteins. Further, we show that the rat POMC distal promoter domain contains a homologous sequence which constitutes a natural mutant of the human POMC E2F binding site, since it does not bind E2F. We show by transient transfection that this natural mutant, in the context of the rat POMC promoter, is not active in DMS-79 cells by contrast to the human POMC E2F binding site. We conclude that E2F binding is required for the activity of Domain IV in DMS-79 cells and contributes to the expression of the POMC gene in SCLC. Further studies are required to elucidate the role of E2F factors in POMC gene transcription in SCLC cells, but our results have identified mechanisms different from those in pituitary corticotroph cells that are used by these SCLC tumor cells.

Multihormone-producing islet cell tumor of the pancreas associated with somatostatin-immunoreactive amyloid: immunohistochemical and immunoelectron microscopic studies

Pancreatic islet cell tumors, especially insulinomas, are often associated with amyloid deposition in the tumor tissue. Biochemical analysis has demonstrated that the amyloid protein from insulinoma is derived from islet amyloid polypeptide (or amylin) that is produced by tumor cells originating from beta cells of the islet of Langerhans. We examined a case of malignant pancreatic islet cell tumor with amyloid deposition in the tumor tissue using immunohistochemistry and double-labeling immunogold electron microscopy. The tumors were composed of cells producing multiple hormones, including somatostatin, gastrin, amylin, insulin, calcitonin gene-related polypeptide, and calcitonin. Amyloid deposits reacted with antisomatostatin antiserum but not with other antisera, including antiamylin. The present study demonstrated for the first time that amyloid associated with islet cell tumors is not always derived from amylin and can come from somatostatin.

Thyroid autoantibodies and thyroid function in patients with pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PA) patients often present high serum titres of several autoantibodies including autoantibodies against beta-islet cells and insulin. In the present study we examined with an hemagglutination method the sera of 33 patients with PA for the presence of both anti-mitochondrial and anti-thyroglobulin antithyroid autoantibodies (ATA). Twenty-six surgical patients with other non-malignant gastrointestinal tract (GI) disease (chronic pancreatitis or hernia) and 40 healthy volunteers were used as controls. Eight of the 33 PA patients were found to have ATA autoantibodies, whereas only one patient with chronic pancreatitis and 2 normal individuals had high serum ATA titres. The difference between the PA patients and either of the control groups was statistically significant (p < 0.05). The production of autoantibodies could be attributed to impaired immunoregulation caused by the malignant cells.

Autoantibodies against insulin and beta-islet cells in pancreatic adenocarcinoma: a possible explanation for diabetes mellitus

To evaluate the prevalence of autoantibodies against the b-islet cells (ICA) and the molecule of insulin (IAA) in the serum of patients with pancreatic adenocarcinoma (PA), we examined the sera of 36 newly diagnosed pancreatic adenocarcinoma patients for the presence of these antibodies, using an enzyme-linked immuno-assay method. These results were correlated with survival. Ten patients with insulin-dependent diabetes mellitus (IDDM) and 21 healthy volunteers were evaluated as age-matched controls. Twenty out of 36 (57%) PA patients were found to have detectable ICA autoantibodies and 17 (48%) PA patients had detectable IAA antibodies. Five out of 10 (50%) and 3 out of 10 (30%) IDDM patients had ICA and IAA antibodies, respectively. None of the healthy volunteers was positive for either of the autoantibodies examined. The difference was statistically very significant and the presence of high serum titers of both autoantibodies was associated with a worse outcome for these patients than for those without such autoantibodies. Our data suggest that the high incidence of diabetes mellitus in patients with PA may be attributed to the presence of these autoantibodies. Further clinical studies are needed to establish the above autoantibodies as prognostic markers of pancreatic cancer.

Unusual endocrine presentations of nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma is endemic in Southern China and the majority of patients present with local symptoms due to the tumor.

METHODS

This report describes two unusual cases of occult nasopharyngeal carcinoma in which the patients initially presented with endocrine manifestations.

RESULTS

The first patient presented with Cushing's syndrome secondary to ectopic adrenocorticotropic hormone (ACTH) production. Nasolaryngoscopy showed a growth in the left nasal fossa and biopsy revealed a poorly differentiated nasopharyngeal carcinoma that exhibited positive immunostaining for ACTH. The second patient presented with a 10-month history of bone pain over both lower limbs. She was normocalcemic but her serum alkaline phosphatase was markedly elevated. A bone biopsy showed both osteoclastic and osteoblastic activity with widespread fibrosis suggestive of Paget's disease. Three months later, she developed third cranial nerve palsy. Computed tomography investigation revealed a soft tissue mass filling the sphenoid and ethmoid sinuses. Biopsy showed a poorly differentiated nasopharyngeal carcinoma. The bone biopsy was reviewed and immunohistochemistry demonstrated the presence of cells positive for the epithelial marker AE1/3 within the fibrous stroma. Radio-labeled in situ hybridization showed that Epstein-Barr virus early RNA was present in these tumor cells and the bone lesions were in fact metastases.

CONCLUSIONS

Nasopharyngeal carcinoma can present with rather atypical symptoms that may lead to a delay in diagnosis. Therefore, in high risk populations, it is important to consider nasopharyngeal carcinoma as a possible primary tumor in patients with occult carcinomas.

Preliminary evaluation of the usefulness of Tc-99m (V) DMSA in pancreatic neuroendocrine tumors

The authors describe the possible application of Tc-99m (V) DMSA scintigraphy in pancreatic neuroendocrine tumors. In consideration of the common embryonic origin of these tumors and other neoplastic diseases (medullary thyroid carcinoma, pheocromocytoma, neuroblastoma) that have been well studied with radionuclide imaging, five cases of pancreatic neuroendocrine tumors (two insulinomas, one vipoma, and two unclassified neuroendocrine tumors) were successfully visualized with Tc-99m (V) DMSA scintigraphy, thus giving an overall "imaging confirmation" of the histologic and/or cytologic results in terms of primary and metastatic localization. The authors point out the importance of their results, obtained in a simple and repeatable manner, and suggest a real comparison in this setting between this approach and octreotide scintigraphy.

Ectopic ACTH syndrome

Ectopic ACTH syndrome represents a cancer-induced amplification of a property [proopiomelanocortin (POMC) peptides production] normally present in the cells from which the cancer originated but with aberrant posttranslational processing of POMC resulting in a greatly elevated secretion of ACTH precursors. The classic ectopic ACTH-producing tumors described in the 1960s were highly malignant but more recently slowly growing tumors such as carcinoids are reported with increasing frequency. Clinical features of patients with ectopic ACTH were analyzed, including biochemical abnormalities, plasma ACTH, cortisol and urinary steroids. Dynamic tests such as high-dose dexamethasone suppression, metyrapone and ovine-CRH (oCRH) stimulation were explored, as well as inferior petrosal sinus ACTH sampling before and after oCRH. Among the tumor markers examined, elevation of ACTH precursors was uniformly present followed by increased output of calcitonin, gut hormones, oncofetal and placental hormones in decreasing order. Since more than 90% of ectopic ACTH tumors are neuroendocrine in nature exhibiting APUD characteristics, their 2 markers, neuron-specific enolase and chromogranins are very useful. The imaging procedures for localization of the tumor ranged from chest X-rays to computed tomography and magnetic resonance of the chest and abdomen. Abdominal ultrasonography was also useful. Finally somatostatin receptor scintigraphy permitted demonstration of unrecognized tumors and/or metastases, even when the tumors were occult. The ACTH content, immunostaining for APUD markers and altered POMC processing were evaluated in ectopic tumors and/or metastases. Occult ectopic ACTH syndrome of more than 4-6 months of symptoms without the emergence of an obvious source was reviewed. Since the tumors are often clinically and biochemically undistinguishable from pituitary-dependent Cushing's disease, inferior petrosal sinus sampling for ACTH after oCRH stimulation established the diagnosis in over 90% of the cases. 60% of the occult tumors were thoracic carcinoids (3/4 bronchial carcinoids), followed by small cell lung cancer and pancreatic neuroendocrine tumors. In 12% the primary etiology was not detected. The rare syndrome of ectopic CRH syndrome (6 published cases) leading to excessive stimulation of the pituitary which became hyperplastic and secreted excessive amounts of ACTH is discussed. Finally, the 12 published cases and 1 unreported patient with ectopic CRH-ACTH tumors were reviewed, the majority being metastatic small cell lung carcinomas, bronchial and thymic carcinoids.

Thyroid autoantibodies and thyroid function in patients with gastric cancer

Antibodies against thyroid antigens are commonly found in patients with chronic gastritis type B (20-30%) and pernicious anaemia (50%), two disorders that predispose to gastric cancer. In addition, thyroid disease in increased incidence has been reported in breast and in colon cancer. In order to determine a) the incidence of antithyroid antibodies (ATA) in gastric cancer, b) the thyroid function in patients with ATA and c) the correlation between ATA and the presence of chronic gastritis, we examined the sera of 32 patients with gastric cancer (GC) for the presence of antithyroglobulin and antimicrosomal antibodies. T3, T4 and TSH values were also measured. The sera of 36 patients with malignant tumours of the GI tract other than stomach (OMT) and of 40 healthy blood donors were used as controls. Three of the 32 GC patients had antithyroglobulin antibodies, 4 had antimicrosomal and one had both types. Of the eight patients with ATA (25%) only two had hypothyroidism and another two histologically diagnosed chronic gastritis. Three sera of the healthy controls and one of the OMT had also antithyroid antibodies. To conclude, a significant number of patients with GC had ATA as compared to controls (p < 0.01) but the presence of ATA did not necessarily indicate an abnormality of thyroid function. The presence of antibodies did not correlate with chronic gastritis type B.

Reproduction and the APUD system

Substantial evidence for involvement of the APUD system in the normal reproductive tract is limited to the prostate gland and uterine cervix. Most supportive data simply documents the presence of neuro-endocrine cells in these tissues. A biological product(s) or role(s) remains to be discovered, but appears likely in the prostate. Tumors possessing cells with APUD characteristics have been described in many reproductive tissues including the prostate, cervix, endometrium, ovary, and testes. These tumors are generally aggressive in behavior, and optimum therapy needs to be determined.

The cellular and molecular basis of the ectopic ACTH syndrome

In recent years the techniques of molecular and cellular biology have made it possible to begin to dissect the origins and behaviour of the ACTH-secreting tumour cell. It is becoming apparent that these tumours represent undifferentiated neuroendocrine cells, and it may be that their peptide-secreting properties may have no more sinister oncological significance. However, an autocrine role for beta-endorphin may confer a selective growth advantage on the POMC-expressing cell. It is still not clear why glucocorticoids fail to inhibit the POMC gene in these extra-pituitary tumours despite the presence of glucocorticoid receptors. This may not be resolved until the mechanism for inhibition of POMC by glucocorticoids in the normal pituitary is understood, although it is tempting to speculate that a mutation in the glucocorticoid receptor or a tissue specific interaction is responsible for the resistance of POMC observed in the ectopic ACTH syndrome. In studying the peptides secreted by the extra-pituitary tumours responsible for the ectopic ACTH syndrome it would appear that direct measurement of ACTH precursors and comparison with the circulating concentrations of ACTH can give valuable information on the percentage of tumours which do not effectively process the ACTH precursors. However, far more data have to be collected on patients with occult tumours in order to identify whether this type of processing is tissue specific. Nevertheless, these studies provide useful insights into the mechanisms of intracellular signalling and regulation in such tumours which may identify unique pharmacological tools to inhibit ACTH secretion or more importantly tumour growth.

Paraneoplastic syndromes associated with lung cancer

Paraneoplastic phenomena associated with primary lung cancer have diverse initial manifestations and epitomize the systemic nature of human malignant disease. The spectrum of clinical features in patients with paraneoplastic syndromes ranges from mild systemic or cutaneous disease to hypercoagulability and severe neuromyopathic disorders. Although the diagnosis is often one of exclusion, an improved understanding of the pathogenesis involved in some of these syndromes has provided another means of recognizing the disorders and perhaps treating the affected patients. Proposed mechanisms of paraneoplastic processes include the aberrant release of humoral mediators such as hormones and hormone-like peptides, cytokines, and antibodies. In this update, we review the potential mechanisms, diagnosis, and treatment of paraneoplastic syndromes associated with lung cancer.

Characterisation of the expression and post-translational processing of the preprotachykinin-I gene and the regulated release of tachykinins by the RINm5F cell-line

Normal transcription and postranslational processing of the preprotachykinin (PPT)-I gene and regulated release of substance P and neurokinin A by the rat pancreatic endocrine cell-line, RINm5F, has been demonstrated, using radioimmunoassays (RIAs), reversed-phase (rp)HPLC and Northern blot analysis. This is the first stable cell-line found to express the PPT-I gene and provides an opportunity for investigating PPT-I gene expression and tachykinin biosynthesis. RIN5mF cells are a model for the pancreatic beta-cell, which is not known to exhibit PPT-I gene expression which may, therefore, be a feature of the transformed state of these cells. These data may imply that the tachykinins are important in pancreatic islet embryogenesis.

Extraplacental human fetal tissues express mRNA transcripts encoding the human chorionic gonadotropin-beta subunit protein

The glycoprotein hormone human chorionic gonadotropin (hCG) is synthesized in large quantities by the developing placenta, reaching peak concentrations in maternal blood during the late first trimester and early midtrimester of pregnancy. In general it is believed that the alpha-subunit of this dimeric hormone is expressed in pituitary gonadotropes, thyrotropes, and trophoblasts, while the beta-subunit is expressed exclusively by trophoblasts. Studies from our laboratory and other laboratories have shown that some midtrimester human fetal tissues, in addition to the placenta, can synthesize proteins that appear to be very similar to the beta-subunit of hCG. To define precisely the nature of this putative hCG-beta-subunit in extraplacental fetal tissues, we have examined the mRNA from a variety of human fetal and adult tissues using nucleic acid hybridization and reverse transcription-polymerase chain reaction (PCR) methods. Our results demonstrate that midtrimester fetal kidney and adrenal tissues contain hCG-beta mRNA transcripts at concentrations comparable to that of placenta, while fetal lung, brain, muscle, and adult adrenal contain only trace to undetectable levels of hCG-beta mRNA. By restriction endonuclease mapping of PCR fragments from fetal tissue cDNAs, we show that the hCG-beta transcript expressed in midtrimester human fetal organs is a bone fide copy of hCG-beta gene No. 5 of the beta-subunit gene family located on chromosome 19.

Postmenopausal uterine bleeding due to estrogen production by gonadotropin-secreting lung tumors

Two postmenopausal women are described who had uterine bleeding due to hormone production by lung tumors--a large cell carcinoma in one case and a choriocarcinoma in the other. Both tumors stained positively for one or more placental peptides (human chorionic gonadotropin [hCG], placental lactogen, or pregnancy-specific beta-1 glycoprotein) and both patients had extremely elevated serum levels of hCG, suggesting the tumors had some placental-like endocrine function. Clinical and hormonal data supported the concept that the uterine bleeding resulted from estrogen excess due to steroid bio-transformation by the tumors.

Small cell (endocrine cell) carcinoma of the gallbladder with squamous and adenocarcinomatous components

Small cell (endocrine cell) carcinoma of the gallbladder in a 62-year-old woman is reported. The palliative cholecystectomy specimen revealed a submucosally invading tumor with extensive hemorrhagic necrosis. At autopsy, performed five months after surgery, a huge tumor measuring 14 x 12 x 8 cm was located at the liver hilus. No signs or symptoms related to overproduction of hormones were recorded throughout her illness. Neither lung lesions nor gall stones were identified. Histologically, diffuse proliferation of small, spindle-shaped atypical tumor cells with numerous mitoses was evident. Intraepithelial tumor cell proliferation in the gallbladder mucosa was seen focally. The neuroendocrine nature of the tumor cells was confirmed by the histologic pattern of growth with pseudo-rosette formation, positive reaction for Grimelius' argyrophilia, neuron-specific enolase and Leu 7, and ultrastructural demonstration of neuroendocrine-type granules. Immunostaining for a variety of hormones was all negative. Characteristically, foci with squamous and adenocarcinomatous differentiation were identified in the tumor tissue. The glandular components were immunoreactive for carcinoembryonic antigen, secretory component, epithelial membrane antigen and CA19-9. The histogenesis and totipotentiality of the neoplasm were discussed.

Neuroendocrine differentiation in lung tumours

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Human chorionic gonadotropin in esophageal carcinomas. An immunohistochemical study

We have examined immunohistochemically the presence of human chorionic gonadotrophin (hCG) in 29 esophageal carcinomas: 24 squamous cell carcinomas, 2 adenocarcinomas, 2 adenoid cystic carcinomas and 1 adenosquamous carcinoma. In hCG-positive tumors, the presence of human placental lactogen (hPL) and pregnancy-specific beta-1 glycoprotein (SP-1) was also assessed. HCG immunoreactive cells were found in 5 squamous cell carcinomas (21%) and in none of 5 non-squamous cell tumors. The hCG positive cells were found in the most infiltrating areas of the tumors where poorly differentiated and pleomorphic cells predominated. The positive tumors were 4 poorly differentiated (31%) and one moderately differentiated carcinoma (12%). Four out of 10 cases (40%) with lymph node metastases had hCG in the primary tumor, whereas only one out of 11 cases (9%) without metastases was hCG positive. HPL and SP-1 were found in two cases. These placental proteins were detected in similar areas than hCG but the number of hPL and SP-1 immunoreactive cells was lower than hCG positive cells. SP-1 was also seen in areas of squamous cell differentiation negative for hCG. None of these two cases showed trophoblastic differentiation.

Human chorionic gonadotropin in esophageal carcinomas. An immunohistochemical study

We have examined immunohistochemically the presence of human chorionic gonadotrophin (hCG) in 29 esophageal carcinomas: 24 squamous cell carcinomas, 2 adenocarcinomas, 2 adenoid cystic carcinomas and 1 adenosquamous carcinoma. In hCG-positive tumors, the presence of human placental lactogen (hPL) and pregnancy-specific beta-1 glycoprotein (SP-1) was also assessed. HCG immunoreactive cells were found in 5 squamous cell carcinomas (21%) and in none of 5 non-squamous cell tumors. The hCG positive cells were found in the most infiltrating areas of the tumors where poorly differentiated and pleomorphic cells predominated. The positive tumors were 4 poorly differentiated (31%) and one moderately differentiated carcinoma (12%). Four out of 10 cases (40%) with lymph node metastases had hCG in the primary tumor, whereas only one out of 11 cases (9%) without metastases was hCG positive. HPL and SP-1 were found in two cases. These placental proteins were detected in similar areas than hCG but the number of hPL and SP-1 immunoreactive cells was lower than hCG positive cells. SP-1 was also seen in areas of squamous cell differentiation negative for hCG. None of these two cases showed trophoblastic differentiation.

v-rasH induces non-small cell phenotype, with associated growth factors and receptors, in a small cell lung cancer cell line

Small cell lung cancer (SCLC) tumor progression can involve partial or complete conversion to a more treatment-resistant non-small cell (NSCLC) phenotype. In a cell culture model of this phenomenon, we have previously demonstrated that insertion of the viral Harvey ras gene (v-Ha-ras) into SCLC cell lines with amplification and overexpression of the c-myc gene induced many NSCLC phenotypic features. We now report that the v-Ha-ras gene can also induce morphologic, biochemical, and growth characteristics consistent with the NSCLC phenotype in an N-myc amplified SCLC cell line, NCI-H249. We show that v-Ha-ras has novel effects on these cells, abrogating an SCLC-specific growth requirement for gastrin-releasing peptide, and inducing mRNA expression of three NSCLC-associated growth factors and receptors, platelet-derived growth factor B chain, transforming growth factor-alpha (TGF-alpha), and epidermal growth factor receptor (EGF-R). TGF-alpha secretion and EGF-R also appear, consistent with the induction of an autocrine loop previously shown to be growth stimulatory for NSCLC in culture. These data suggest that N-myc and v-Ha-ras represent functional classes of genes that may complement each other in bringing about the phenotypic alterations seen during SCLC tumor progression, and suggest that such alterations might include the appearance of growth factors and receptors of potential importance for the growth of the tumor and its surrounding stroma.

Differential utilization of calcitonin gene regulatory DNA sequences in cultured lines of medullary thyroid carcinoma and small-cell lung carcinoma

Regulation of expression of the human calcitonin gene was found to differ between two tumor lines of different tissue origin, medullary thyroid carcinoma (TT line) and small-cell lung carcinoma (DMS53 line). Distal 5' DNA elements between -750 and -2000 exhibited a stronger basal activity in DMS53 than in TT cells, whereas proximal DNA sequences between -132 and -252 mediated a dramatic cyclic AMP response in TT but not DMS53 cells.

Differential utilization of calcitonin gene regulatory DNA sequences in cultured lines of medullary thyroid carcinoma and small-cell lung carcinoma

Regulation of expression of the human calcitonin gene was found to differ between two tumor lines of different tissue origin, medullary thyroid carcinoma (TT line) and small-cell lung carcinoma (DMS53 line). Distal 5' DNA elements between -750 and -2000 exhibited a stronger basal activity in DMS53 than in TT cells, whereas proximal DNA sequences between -132 and -252 mediated a dramatic cyclic AMP response in TT but not DMS53 cells.

"APUD" cells: fact and fiction

Pearse's "APUD" cell theory helps define the ontogeny and differentiation programs of small polypeptide hormone-secreting cells of diverse tissue origins. Cells with such features may arise through one of multiple related pathways of epithelial cell differentiation ongoing in tissues of all embryonic lineages.

Endocrine neoplasms (non-gastrin) of the pancreas

Although neoplasms that produce gut regulatory peptides and amines can be found throughout the gastroenteropancreatic axis (excluding carcinoids), the vast majority of these lesions are found within the pancreas. Recognition of the various clinical syndromes produced by the secretions of these tumors, the development of sensitive and specific radioimmunoassays for the elaborated peptides, and development of more effective localization techniques have contributed to earlier diagnosis and marked improvement in patient care. Treatment is directed toward medical management to correct the metabolic disturbances produced by the excessive amounts of gut regulatory peptides, followed by localization and extirpation of tumor. In the presence of unresectable tumor or metastases, palliative treatment directed at reducing peptide secretion or preventing its effects by surgery, chemotherapy, hormonal therapy, and hepatic-artery embolization can produce long-term remission of symptoms. Because the majority of these tumors are malignant, the ultimate goal in successful patient management is the early detection and surgical excision of the islet cell tumor before metastases occur.

Three cases of oral squamous cancer associated with leukocytosis, hypercalcemia, or both

Three examples of malignant neoplasms primary to the oral cavity and associated with paraneoplastic syndromes are presented. The first case is a squamous cell carcinoma of the maxilla associated with leukocytosis. The second case is a mandibular squamous cell carcinoma associated with hypercalcemia in the absence of bony metastases. The third case is a squamous cancer of the tongue that metastasized to the lumbar vertebrae and right second rib and was associated with both hypercalcemia and leukocytosis. There was no evidence of acute infection or leukemia that could be expected to account for leukocytosis. Hypercalcemia in the second case was defined as humoral hypercalcemia of malignancy by biochemical and clinical evaluations. To our knowledge, this is the first definitive report of a carcinoma primary to the oral cavity associated with humoral hypercalcemia of malignancy. In each case, the severity of hypercalcemia, leukocytosis, or both very closely correlated with tumor growth. Surgical excision of the tumors or regression of tumor mass due to aggressive anticancer drug administration resulted in decreases in leukocyte number, serum calcium level, or both. In contrast, recurrence or regrowth of tumors induced further development of hypercalcemia, leukocytosis, or both. It is therefore likely that humoral factors released by these oral carcinomas are responsible for the hypercalcemia, leukocytosis, or both.

Structure and methylation of the human calcitonin/alpha-CGRP gene

We report a detailed analysis of the human calcitonin/alpha-CGRP gene locus. About 39kb of DNA containing the gene has been mapped and a common Pvu II RFLP identified downstream of the gene. DNA sequence analysis revealed an extensive CpG island containing several rare restriction enzyme sites at the 5' end of the gene. The structure of this island is unusual in that it contains two distinct CpG-rich regions, one located around exon 1 and the other about 1.5kb further upstream. Msp I sites within both CpG-rich regions were found to be unmethylated, regardless of whether the calcitonin/alpha-CGRP gene was being expressed. However, a correlation was found between demethylation of Msp I sites in intron 2, downstream of the CpG island, and calcitonin/alpha-CGRP gene expression. DNA sequence analysis also revealed the presence of several binding sites for constitutive and regulatory transcription factors in the promoter of the gene. These results suggest that both unmethylated CpG islands and specific demethylation of internal sequences may play a role in the activation of calcitonin/alpha-CGRP gene transcription.