Expression in human lung cancer cell lines of genes of prohormone processing and the neuroendocrine phenotype

Lung tumor cells and cell lines, principally the histologically classified small cell lung cancer, are characterized by the expression of neuroendocrine (NE) features including AADC (aromatic amino acid decarboxylase, previously called DOPA decarboxylase) and the production of many peptide hormones. The general mechanisms by which most aspects of the NE phenotype affect the clinical behavior of lung tumor cells are unknown, but it is well recognized that peptide hormones can have systemic effects (paraneoplastic syndromes) and several have been shown to be autocrine growth factors for cancer cells. In order to determine the relationship between expression of different aspects of the NE phenotype in lung cancer cell lines, we have compared expression of a gene required for biosynthesis of some active peptide hormones (PAM, peptidylglycine alpha-amidating monooxygenase) to the gene for AADC in 32 lung cancer cell lines. Expression of these genes was quantified by both steady state Northern blot analysis and radiochemical enzymatic activity measurements. To ensure a range of expression of NE markers, non-small cell lung cancer (NSCLC) cell lines were chosen to include several which had previously been shown to express NE markers, and several small cell lung cancer (SCLC) cell lines with previous low levels of AADC were included. PAM enzyme activity and Northern blot analysis showed a two to three log variation in levels of expression in both the small cell and non-small cell lines. A smaller range was found for AADC expression. Using the highly sensitive PAM enzyme assays, all cell lines were found to express detectable PAM. PAM activities were secreted into the growth medium of all cell lines. There was no simple correlation apparent between AADC and PAM gene expression in the lung cancer cell lines. However, classic small cell lines demonstrated high levels of expression of both PAM and AADC genes, as did the carcinoid subset of the NSCLC lines. NSCLC lines expressed levels of PAM mRNA and enzyme activities equivalent to those of SCLC but had infrequent expression of AADC (principally only carcinoid NSCLC expressed AADC). These data demonstrate that separate aspects of the NE phenotype can be differentially expressed in lung cancer histological sub-types. Expression of PAM enzymes in all sub-types of lung cancer suggests that peptide prohormone activation may be a common mechanism for autocrine growth stimulation even in non-Ne NSCLC cell lines, or may reflect maintenance in cell lines of a common pathway of lung tumor promotion.

Simultaneous exposure to nicotine and hyperoxia causes tumors in hamsters

BACKGROUND

We have shown that the nicotine-derived nitrosamine 4-(methyl-nitrosamino)-3-(pyridyl)-1-butanone (NNK) causes a high incidence of neuroendocrine lung tumors in male Syrian golden hamsters when administered to animals maintained in an atmosphere of 60% hyperoxia. In vitro studies with fetal hamster pulmonary neuroendocrine cells (PNE cells) and human neuroendocrine lung cancer cell lines revealed that nicotine and NNK are both potent mitogens for normal and neoplastic PNE cells when the cells were maintained in an atmosphere of high CO2. These effects were completely inhibited by antagonists of nicotinic acetylcholine receptors (nAChR). NNK displaced 3H-(-)L-nicotine from the nAchR in radioreceptor assays with cell membrane fractions from hamster lungs enriched in PNE cells. We therefore hypothesized that NNK acts as an agonist of the nAchR in PNE cells and that stimulation of this receptor in an environment of impaired pulmonary oxygenation is an important molecular event leading to the development of lung tumors with a neuroendocrine phenotype.

EXPERIMENTAL DESIGN

To test this hypothesis, we exposed male Syrian golden hamsters maintained in 60% hyperoxia to s.c. injections of nicotine for the duration of their life. To allow for a survival time long enough to assess a potential carcinogenic effect of this treatment, animals demonstrating symptoms of respiratory distress were returned to ambient air for 24 hours throughout the experiment.

RESULTS

A low but significant number of the animals exposed to hyperoxia and nicotine developed tumors of the nasal cavity, lungs, and adrenal glands. All of the tumor-bearing animals had survived 40 weeks or longer. The lung tumors demonstrated focal areas of positive immunoreactivity to neuron-specific enolase (NSE) and 5-hydroxy-tryptamine (5-HT, serotonin), both of which are markers of neuroendocrine differentiation. Hamsters maintained in ambient air and receiving identical injections with nicotine as well as animals maintained in hyperoxia and injected with saline did not develop tumors in any organs. All hamsters exposed to hyperoxia and surviving more than 12 weeks had thickened alveolar walls and emphysema.

CONCLUSIONS

Our data support the hypothesis that chronic stimulation of the nAChR in an environment of impaired pulmonary oxygenation contributes to the carcinogenic burden associated with exposure to cigarette smoke and provides selective growth advantage for lung tumors with a neuroendocrine phenotype.

Neuroendocrine neoplasms of the larynx

Neuroendocrine neoplasms of the larynx are a rare group of tumors that include carcinoid tumor, atypical carcinoid tumor, and small cell carcinoma. These neoplasms pose interesting diagnostic, prognostic, and therapeutic dilemmas, and they are, as a whole, aggressive tumors with a tendency for local and distant spread. The authors of this study examined six new cases of laryngeal neuroendocrine neoplasms. One case manifested itself as a primary atypical carcinoid tumor and caused a "carcinoid syndrome." The remaining five cases were small cell carcinomas of the larynx. Histologic, immunocytochemical, DNA flow cytometric, and p53 studies were performed on all cases. The expression of neuron-specific enolase and chromogranin were the most useful markers in this group of tumors. Overexpression of p53 protein was present in the majority of cases, including the atypical carcinoid tumor. The implications of these studies for diagnosis, classification, and treatment are discussed.

Neoplastic endocrine cells in prostatic carcinoma: a case report with immunocytochemical and electron microscopic findings

A case of a 68-year-old male with prostatic carcinoma which was partially well differentiated but largely poorly differentiated is presented in this report. The poorly differentiated area of the adenocarcinoma seemed to arise from the well-differentiated portion. The former was populated with Grimelius argyrophilic cells, and occasionally contained round, eosinophilic intracytoplasmic inclusions which appeared to be composed of a secretory substance. Immunocytochemistry revealed that endocrine cells were present in the normal portion of the gland as well as in the well-differentiated adenocarcinoma, but were more numerous in the poorly differentiated portion. The latter portion was positive for chromogranin A, endocrine granule constituents, neuroendocrine markers, serotonin, Leu 7, ACTH and neuron specific enolase. In addition, cells of poorly differentiated portion were reactive with CEA, prostatic acid phosphatase and human prostate specific antigen. Ultrastructural features observed in the poorly differentiated adenocarcinoma included five kinds of round neurosecretory granules. This was a rare case of prostatic adenocarcinoma in which the evolution from well differentiated to poorly differentiated tissue containing neuroendocrine constituents could be clearly observed.

In situ hybridization analysis of chromogranin A and B mRNAs in neuroendocrine tumors with digoxigenin-labeled oligonucleotide probe cocktails

The chromogranin/secretogranin (Cg/Sg) molecules are a family of acidic proteins present in neuroendocrine cells and tumors with secretory granules. They have been frequently used to characterize neuroendocrine cells and tumors by immunohistochemical analyses. Immunoreactivity for CgA is related to the presence of secretory granules in these tumors, so immunohistochemical staining for CgA may be absent in neuroendocrine tumors with only a few secretory granules. RNA in situ hybridization with a series of oligonucleotide probes for CgA and CgB was used to detect the mRNA transcripts for CgA and CgB with digoxigenin-labeled probes in 31 neuroendocrine tumors. These results were compared to ISH with 35S-labeled probes and with immunohistochemical staining for CgA and synaptophysin in the same neoplasms. ISH with 35S-labeled probes for CgA and B detected mRNA transcripts in 31 of 31 tumors, whereas the digoxigenin-labeled probe cocktails for CgA and B were positive in 19 of 31 cases when used separately and in 24 of 31 cases when used together. Immunohistochemical staining for CgA was positive in 22 of 31 cases and for synaptophysin in 23 of 31 cases. The CgA and B oligonucleotide probe cocktails were highly specific, since nonneuroendocrine cells and tumors did not stain and the hybridization signal was abolished by ribonuclease A pretreatment. These results indicate that non-isotopic ISH with digoxigenin-labeled probe cocktails for CgA and B or with 35S-labeled probes can be used in characterizing neuroendocrine cells and tumors in formalin-fixed paraffin-embedded tissue sections even when the CgA protein is not detected by immunohistochemistry.

Florid vascular proliferation associated with neural and neuroendocrine neoplasms. A diagnostic clue and potential pitfall

We report the light microscopic and immunohistochemical features of vascular proliferations associated with 26 extracranial neural and neuroendocrine neoplasms including esthesioneuroblastoma, neuroblastoma/ganglioneuroblastoma, the primitive neural component of immature teratoma, mediastinal teratoma, primitive neuroectodermal tumor, intra-abdominal desmoplastic small cell tumor, Merkel cell carcinoma of the skin, and thyroid medullary carcinoma. These vascular proliferations were similar to those associated with high-grade glial neoplasms and were characterized by tufts of vessels with a glomeruloid configuration or by long cords of vessels. Immunohistochemical evaluation documented the presence of endothelial cells, perithelial cells, and basement membrane components within the foci of proliferating vessels. We propose that these vascular proliferations represent a characteristic feature of the neuroendocrine/neural neoplastic phenotype and that they possibly arise as the result of angiogenic factors produced by the neoplastic cells. The presence of these distinctive vascular lesions in the stroma of a poorly differentiated neoplasm should alert the pathologist to the possibility of the neoplasm being of a neural or neuroendocrine nature.

Immunohistochemical distribution of chromogranins A and B and secretogranin II in neuroendocrine tumours of the gastrointestinal tract

The aim of the present study was to investigate immunohistochemically the distribution of chromogranin A, chromogranin B, and secretogranin II in a series of 152 neuroendocrine tumours of the gastrointestinal tract. Tumour tissues from 25 argyrophil gastric carcinoids, 18 gastrin and 5 somatostatin-producing tumours, 4 'gangliocytic paragangliomas', 49 classical argentaffin and 2 L cell appendiceal carcinoids, 27 classical ileal carcinoids, 17 rectal carcinoids, and 5 poorly differentiated neuroendocrine tumours of the stomach and rectum were immunostained with antibodies against chromogranin A, chromogranin B, and secretogranin II. Chromogranin A was the major granin expressed in gastric carcinoids and in serotonin-producing carcinoids of the appendix and the ileum. In contrast, strong chromogranin B and secretogranin II immunoreactivity was found in rectal carcinoids, in which chromogranin A was rarely expressed. Since chromogranin A is a widely used marker for neuroendocrine differentiation, it is of diagnostic importance that some gastrin-producing tumours, 'gangliocytic paragangliomas', poorly differentiated neuroendocrine carcinomas, and appendiceal L cell carcinoids completely lacked chromogranin A positivity. It is concluded that the various neuroendocrine tumours of the gastrointestinal tract show distinctly different patterns of granin expression, probably reflecting their histogenetical origin.

Endocrine tumors of the small and large intestine

Among endocrine tumors arising in the intestinal tract, midgut argentaffin EC cell carcinoids, duodenal gastrin cell tumors and rectal trabecular L cell carcinoids, in order of decreasing frequency, are those better represented. Together they account for more than 80% of such tumors. Duodenal somatostatin cell tumors, gangliocytic paragangliomas and poorly differentiated neuroendocrine carcinomas, are also well defined tumor entities. The carcinoid syndrome with intermittent flushing, hypotension and diarrhea, and the Zollinger-Ellison syndrome with severe peptic ulcer disease, are the only hyperfunctional syndromes consistently found in association with these tumors. The carcinoid syndrome arises in about 10% of intestinal carcinoids, usually in their advanced metastatic stage. The Zollinger-Ellison syndrome occurs in association with about 40% of gastrin cell tumors, including small intramural growths. Tumor prognosis depends on mode and site of presentation, histology, cell type(s), size, level of invasion, metastases (especially distant metastases) and associated clinical syndrome or background disease.

[Primary and metastatic hepatic cancer: the surgical option]

Major hepatic resection is the treatment of choice in patients with primary and secondary liver cancer. During a 22-month period 31 men and 27 women (mean age 63 years, range 14-84) with space-occupying hepatic lesions were admitted. All 15 patients with benign lesions were operated, except for 3 in whom a liver abscess was drained percutaneously. Of the 43 with malignant liver lesions, 30 had liver metastasis secondary to colorectal cancer, 15 of whom underwent major, anatomical and nonanatomical, liver resection and 1 had cryoablation of the tumor. 9 had hepatocellular carcinoma, 1 of whom had a 4-segment non-anatomical resection and 1 tumor cryoablation. 2 with metastasis from a neuroendocrine tumor had anatomical resection of liver lobes. Of 2 with liver metastasis secondary to breast cancer, 1 underwent resection. CT portography, intraoperative ultrasonography and intraarterial injection of Lipiodol were found to be very useful in selecting patients for liver resection.

Expression of transforming growth factor alpha and its receptor in human neuroendocrine tumours

Transforming growth-factor-alpha (TGF-alpha) is a 50-amino-acid polypeptide that binds to the epidermal growth factor (EGF) receptor and stimulates cell growth. It has been suggested that enhanced production of TGF-alpha and EGF receptors by tumour cells promote tumour-cell growth by autocrine mechanisms. In the present study we have investigated the expression of TGF-alpha and EGF receptors in human neuroendocrine tumours, including midgut carcinoid tumours, phaeochromocytomas and medullary thyroid carcinomas. TGF-alpha expression was demonstrated in biopsies of all tumours examined (n = 30) and EGF receptors in a majority of tumours by Northern analysis and/or immunocytochemistry. Expression of TGF-alpha and EGF receptors was also demonstrated in primary cultures of tumour cells. Carcinoid tumours and phaeochromocytomas in culture secreted detectable amounts of TGF-alpha into the culture medium (400-700 pM). The amount of secreted TGF-alpha could be suppressed by octreotide treatment in individual tumours. Administration of exogenous TGF-alpha stimulated carcinoid tumour growth in vitro as determined by the DNA contents of cell cultures. The growth-stimulatory effect of TGF-alpha could be partially blocked by the use of neutralizing anti-EGF receptor monoclonal antibodies (MAbs). In conclusion, several human neuroendocrine tumours express both TGF-alpha and EGF receptors in in vivo and in vitro, suggesting that TGF-alpha may regulate tumour-cell growth by autocrine mechanisms.

[Middle ear tumor of neuroendocrine nature]

Middle ear neuroendocrine neoplasms are rare and of benign behaviour. Diagnosis is difficult since they produce non-specific symptoms. Electron microscopy and immunochemistry are necessary. We present a carcinoid tumor in a 28-year-old man with one side deafness. He underwent tympanoplasty, staying free of recurrences two years and a half later.

Somatostatin receptor subtypes in neuroendocrine tumor cell lines and tumor tissues

Somatostatin receptor scintigraphy (SRS) is positive in approximately 80% of all patients who have been found to have neuroendocrine (NE) gastroenteropancreatic (GEP) tumors. The reasons for negative results are unclear. The aim of the present study was identification of the specific somatostatin receptor (SSTR) subtypes that are responsible for the in vivo binding of the widely used somatostatin (SST) analogues octreotide and lanreotide in human neuroendocrine gastroenteropancreatic tumors. Ten patients were subjected to SRS with radiolabeled octreotide. Following surgical resection, tumor tissues were analyzed for SSTR subtype mRNA expression by the reverse transcription-polymerase chain reaction (RT-PCR). In addition, SSTR subtype transcripts were investigated by Northern blot analysis and RT-PCR in neuroendocrine tumor cell lines. Expression of SSTR at the protein level was studied by chemical cross-linking experiments. Three patients were negative by SRS. However, RT-PCR revealed most prominently SSTR 2 expression in all tumor specimens. In addition, all tumor tissues analyzed by chemical crosslinking exhibited SST-14 binding sites, indicating that at least some NE tumors were false-negative on SRS.

[Laryngeal neuroendocrine carcinoma. Report of a clinical case]

A case of neuroendocrine small cell carcinoma is described in a 79 year-old male. This tumor is an unusual laryngeal carcinoma (the incidence is slightly lower than 1% of all carcinomas) with an aggressive biological behaviour. This work analyzes its clinical, pathological, therapeutical and evolutive aspects, and compare this case to those reported in the literature.

The expression profile of alternatively spliced neuronal c-src RNA distinguishes between human tumours of the sympatho-adrenal lineage

Human neuronal and neuroendocrine tumour specimens and cell lines were analysed regarding proteins and transcripts coded by the proto-oncogene c-src. At the protein level, most of the neuroblastomas and phaeochromocytomas expressed the neuronal c-src form, pp60c-srcN. None of the other neuroendocrine tumours, i.e. paragangliomas, neuroendocrine pancreatic tumours, or carcinoid tumours and small-cell lung carcinomas of different types, appeared to express the neuronal form. In the brain, c-src is transcribed into 3 differently spliced mRNA variants, c-src, c-srcNI, and c-srcNI+NII. The expression of these transcripts was analysed by PCR amplification of fragments covering the mini-exons I and NII of the corresponding cDNAs. The PCR products were analysed by Southern hybridization and characterized by determination of their sequences. Neuroblastomas, paragangliomas, retinoblastomas and the phaeochromocytomas expressed neuronal c-src splice variants. However, whereas neuroblastomas and retinoblastomas contained all 3 transcripts, the phaeochromocytomas and paragangliomas expressed, with 2 exceptions, only the c-src and the c-srcNI+NII mRNA species. To assess whether neuroblastomas display adrenal chromaffin characteristics, they were analysed regarding expression of the chromaffin marker enzyme, phenylethanolamine-N-methyl transferase. Whereas phaeochromocytomas were positive, all neuroblastomas were immuno-chemically negative for this enzyme. These results and the c-src expression profile suggest that neuroblastomas, including those with an adrenal location, do not originate from the adrenal chromaffin differentiation lineage. The data further suggest neuronal c-srcNI mRNA as a marker for sympathetic neuronal cells of the sympatho-adrenal lineage.

Immunolocalization of neuropeptide Y in human pancreatic endocrine tumors

Neuropeptide Y (NPY) is a 36 amino acid peptide known to inhibit glucose-stimulated insulin secretion. NPY has recently been shown to be synthetized within rat islets of Langerhans and to be secreted in a differentiated rat insulin-secreting cell line, and as to this date the localization of NPY in human endocrine pancreas has not been reported. As NPY shares high amino acid sequence homology with peptide YY (PYY) and pancreatic polypeptide (PP), the polyclonal antibodies raised against these peptides often cross-react with each other. To demonstrate the presence of NPY in the human endocrine pancreas, we used a highly specific monoclonal antibody raised against NPY and another against its C-flanking peptide (CPON). We studied three cases of hyperplasia of Langerhans islets and 11 cases of endocrine tumors of the pancreas. NPY and CPON were detected in all three cases of hyperplasia. For the 11 pancreatic tumors, five and nine of the tumors were positive for the antibodies NPY and CPON, respectively. The two negative tumors for CPON immunoreactivity were differentiated insulinomas, which showed no evidence of other hormonal secretion. In normal Langerhans islet, NPY and CPON immunoreactivities were colocalized in glucagon-producing cells (alpha-cells) and in a few insulin-secreting cell (beta-cells).(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroendocrine metastases of the liver

Neuroendocrine liver metastases are rare, yet they represent an entity that has attracted much attention lately. The protracted course of neuroendocrine tumors and the hormone origin of their typical incapacitating symptoms constitute a logical basis for well founded and bespoke treatment. Demonstration of the liver secondaries is best done by ultrasonography (US) and contrast-enhanced computed tomography (CT), which on the whole have replaced the invasive angiography techniques. By use of histochemical and molecular biologic methods the exact nature of the tumor can be typified in tissue samples obtained percutaneously, laparoscopically, or surgically. Localization of nonpalpable metastases of the liver is best done by intraoperative US. Surgical removal of liver metastases is curative in some cases and is usually effective in relieving the symptoms. Also, palliative debulking or cytoreductive surgery is often worthwhile as it offers a chance of prolonged survival and symptom relief. Similar benefits are achieved by ischemic therapy preferably by temporary dearterialization, which in our department is done on an outpatient basis using a specially designed (externally controlled) occluder applied during a single laparotomy that includes debulking when appropriate as well as cholecystectomy. Hormonal therapy with somatostatin analogs may be used as a single treatment or in combination with ischemic therapy. It has an ensured symptom-reducing effect, whereas its influence on tumor growth is unsettled. Lately similar effects have been ascribed to human leukocyte interferon. In conclusion the specific characteristics of neuroendocrine tumors and the available treatment arsenal favor an active treatment approach in patients who have developed liver metastases.

[Ossified bronchial neuroendocrine tumors: 3 cases]

Large calcium deposits can occur in neuroendocrine tumours of the bronchi and have been observed more frequently with the development of tomodensitometry which is now used for the diagnosis of calcified lung tumours including neuroendocrine tumours. The knowledge of such calcified images should not however mask the possibility of a malignant tumour.

Carcinomas of the breast with endocrine differentiation: a review

The occurrence of endocrine differentiation in some mammary carcinomas seems well-established, but pathologists continue to debate its significance. Contemporary thinking suggests that endocrine tumours of the breast do not constitute a single clinicopathological entity with a consistent histogenesis but rather that endocrine differentiation represents a pathway of neoplastic development available to a range of breast cancers. This pattern of differentiation occurs in tumours with vastly different morphological appearances, such as: ductal carcinoma in situ, mucinous carcinoma, a variant of lobular carcinoma, and low grade invasive ductal carcinoma. Although such tumours share some characteristics with intestinal endocrine neoplasms, the typical pattern of intestinal carcinoid virtually never occurs in mammary lesions. Conventional microscopy permits the diagnosis in most cases. Specialized techniques (histochemistry, immunohistochemistry, and electron microscopy) can serve as the basis for diagnosis in the absence of the appropriate morphological features. Although the system of nomenclature proposed by the World Health Organization for use with endocrine tumours in other organs can be used for endocrine tumours of the breast, only a minority of lesions will fit the established criteria. Most lesions are classifiable in the conventional categories of mammary carcinomas. No special prognostic significance is attached to these tumours at the present time.

Impact of neuroendocrine differentiation in non-small cell lung cancer. The LCSG experience

Non-small cell lung cancers with neuroendocrine differentiation (NSCLC-NE) may demonstrate biologic behavior intermediate between non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) with impact on prognosis. We studied the expression of four well-defined neuroendocrine (NE) markers: neuron-specific enolase (NSE), chromogranin A, Leu-7, gastrin-releasing peptide, and a panel of three non-NE markers, including vimentin, and the epithelial markers carcino-embryonic antigen (CEA) by immunohistochemistry, and mucin by histochemistry in 237 resected NSCLCs from patients on six LCSG protocols. Twenty-nine (12%) tumors were positive for 2 or more NE markers. An NE differentiation score was calculated but failed to correlate with recurrence as did other combinations of markers. However, the presence of tissue staining for CEA was strongly associated with improved survival (p = 0.011), whereas the presence of mucin was associated with a worse outcome (p < 0.001). Individually, CEA and mucin remained prognostic even when corrected for stage, histologic features, and performance status. We conclude that NE differentiation is not predictive of recurrence in patients with resected NSCLC but data on patterns of CEA and mucin expression may improve prognostication and permit rational design of new therapeutic approaches.

Gastrointestinal neuroendocrine cell proliferations

The gastrointestinal neuroendocrine cell proliferations are comprised of a few hyperplasias and various neoplasias. The better characterized hyperplasias include G-cell hyperplasia, either primary or secondary, enterochromaffin-like (ECL)-cell hyperplasias, generally secondary to hypergastrinemia, and EC-cell hyperplasias. The neoplasias include carcinoid tumors, demonstrating low malignancy and divided into foregut, midgut, and hindgut varieties, poorly differentiated neuroendocrine carcinomas resembling their pulmonary counterparts the "oat cell" carcinomas both in histological pattern and in their highly malignant behavior mixed endo-exocrine tumors, which in turn can be divided into composite tumors formed by a population of endocrine cells and a population of exocrine cells, and amphicrine tumors formed by a uniform population of cells with a mixture of endocrine and exocrine phenotypic traits. Although some of these mixed tumors show a degree of malignancy intermediate between the classical carcinoid and an adenocarcinoma, more information must be gathered to establish firm prognostic parameters for these relatively new entities.

Variable regions of chromosome 11 loss in different pathological tissues of a patient with the multiple endocrine neoplasia type I syndrome

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder characterized by nodular proliferation of the parathyroid glands and tumors of the anterior pituitary gland, the endocrine pancreas, and the neuroendocrine cell system of the gut. Loss of the putative tumor suppressor effect of the MEN1 gene is probably responsible for the development of MEN1-associated tumors. We report here a genetic study of a female MEN1 patient with the association of nodular hyperplasia of two parathyroid glands, an insulinoma, multiple duodenal gastrinomas, a prolactinoma, and a gastric carcinoid. We performed loss of heterozygosity (LOH) studies of chromosome 11 on all affected tissues except the insulinoma. Allelic losses of chromosome 11 were detected in several tumors, but the chromosomal regions of LOH were different, suggesting that different somatic mutational events are involved in the pathogenesis of these tumors. LOH of chromosome 11 was also detected in the prolactinoma of this patient, which indicates that the MEN1 gene has a tumor suppressor effect in the pituitary.

Hepatic radioembolization with yttrium-90 containing glass microspheres: preliminary results and clinical follow-up

The treatment of hepatic tumors remains unsatisfactory. These lesions receive most of their blood supply from the hepatic artery, therefore the hepatic artery administration of beta-emitting particulate radiopharmaceuticals is an attractive approach to deliver therapeutic irradiation to the liver and differentially to tumors within the liver.

METHODS

A Phase I dose escalation study of the hepatic tolerance to radiation delivered by 90Y containing glass microspheres was carried out in 24 patients with hepatic malignancy. Doses of 90Y microspheres to achieve an estimated whole-liver nominal absorbed radiation dose of 5000 cGy (two patients), 7500 cGy (six patients), 10,000 cGy (seven patients), 12,500 cGy (six patients), and 15,000 cGy (three patients) were administered via the hepatic artery. The administered nominal absorbed radiation dose (NARD) was estimated based on liver volume determined from CT scans and the assumption of uniform distribution of microspheres throughout the liver.

RESULTS

No hematologic, hepatic or pulmonary toxicity was encountered in the dose range examined during a mean follow-up period of up to 53 mo. Reversible gastritis or duodenitis was encountered in four patients without imaging or biopsy evidence for extrahepatic deposition of microspheres. Response data, based on CT scans obtained 16 wk after treatment, showed progressive disease in eight patients, stable disease in seven patients, minimal response in four patients and partial response in five patients. Subsequent follow-up revealed three long-term survivors at 204, 216 and 228 wk.

CONCLUSIONS

These preliminary data demonstrate that in the examined dose range, radiation may be safely delivered to liver tumors by means of 90Y glass microspheres with encouraging response data.

Expression of somatostatin receptors in normal, inflamed, and neoplastic human gastrointestinal tissues

The multiple actions of somatostatin are mediated by specific membrane-bound receptors present in all somatostatin target tissues, such as brain, pituitary, pancreas, gastrointestinal tract, and kidney. For instance, in the human gastrointestinal tract, three different types of tissue compartments express somatostatin receptors: the gastrointestinal mucosa, the peripheral nervous system, and the gut-associated lymphoid tissue, where the receptors are preferentially located in germinal centers. In all these cases, somatostatin binding is of high affinity and specific for bioactive somatostatin analogues. Somatostatin receptors are also expressed in pathological states, such as cancers. A particular abundance is found in neuroendocrine tumors of the gastrointestinal tract. Ninety percent of the carcinoids and a majority of islet cell carcinomas, including their metastases, usually have a high density of somatostatin receptors. Several different somatostatin-receptor subtypes can be expressed by these tumors, the SSTR2 subtype being the most frequently and abundantly expressed. The somatostatin receptors in tumors are identified with in vitro-binding methods, molecular biology techniques, or in vivo-imaging techniques; the latter allow the precise localization of the tumors and their metastases in the patients. Because somatostatin receptors in human gastroenteropancreatic tumors are functional, their identification can be used to predict the therapeutical efficacy of octreotide to inhibit excessive hormone release. Of differential diagnostic importance is the fact that other pathological processes in the gastrointestinal tract may be associated with a high density of somatostatin receptors. Ninety percent of lymphomas, including those with intestinal involvement express somatostatin receptors. Furthermore, a moderate number of colorectal carcinomas contain somatostatin receptors, whereas exocrine pancreatic carcinomas do not. Finally, an increased expression of SS receptors in nonneoplastic conditions, such as in intestinal veins in inflammatory bowel disease, has been recently observed. These observations demonstrate the ability of the human body to regulate SS receptors in a wide number of tissues and conditions.

Dynamic Gd-DOTA-enhanced MR imaging of hepatic metastases from pancreatic neuroendocrine tumors

The aim of this study was to determine the MR imaging features of hepatic metastases from pancreatic neuroendocrine tumors (HMPNT), and to assess their enhancement characteristics on dynamic gadolinium-chelate-enhanced MR imaging. Twelve consecutive patients with pathologically proven HMPNT underwent spin-echo (SE) and dynamic gradient-recalled echo (GRE) MR imaging before and after intravenous administration of a gadolinium-chelate (gadolinium tetraazacyclododecanetetraacetic acid; Gd-DOTA). MR examinations were performed prospectively and interpreted retrospectively in consensus by two radiologists. Fifty-five HMPNT were identified in matching anatomic sections on the different MR sequences and included in the study. On T1-weighted SE images, 45 HMPNT (82%) were hypointense and 10 HMPNT (18%) were isointense. On T2-weighted SE images 55 HMPNT (100%) were hyperintense. On GRE images obtained 20 s after Gd-DOTA injection, 41 HMPNT (75%) showed slight peripheral enhancement, and 14 HMPNT (25%) showed internal enhancement. Forty-four HMPNT (80%) were heterogeneous. On GRE images obtained 4 min after Gd-DOTA injection, 37 HMPNT (67%) showed peripheral enhancement, and 18 HMPNT (33%) showed a global and almost complete enhancement. Heterogeneity of enhancement was seen in all 55 HMPNT (100%). Although HMPNT exhibit a large spectrum of MR features, early enhancement and heterogeneity on dynamic GRE MR images are suggestive features of HMPNT.

Systemic argyria

A 74 year old man presented with signs and symptoms of mild cardiac failure. His face and chest were severely discoloured, which was thought to be due to cyanosis. He deteriorated and died of bronchopneumonia. At post mortem examination multiple organs, including the skin, showed silver pigment deposition; he also had a gastric malignant neuroendocrine tumour. He gave no history of contact with silver compounds. Systemic argyria caused by chronic ingestion of silver compounds is a rare condition which, apart from its cosmetic effects, is thought to be relatively harmless; it is not thought to be carcinogenic. This condition can pose diagnostic problems for both clinicians and pathologists.

Nonfunctioning cystic neuroendocrine neoplasms of the pancreas

BACKGROUND

Three types (functioning solid, nonfunctioning solid, and functioning cystic) of neuroendocrine neoplasms (benign and malignant) of the pancreas have been reported.

PATIENTS

We report three patients with nonfunctioning neuroendocrine neoplasms of the pancreas with cystic components, a type of neoplasm not previously reported. One of the neoplasms we report was benign; the other two were malignant. The patients were admitted with abdominal pain. In each case an abdominal computed tomography scan defined a large multicystic pancreatic mass.

RESULTS

In all instances, immunochemical staining was positive for neuroendocrine markers, confirming the neuroendocrine nature of the tumors. The nonfunctional nature of the neoplasms was confirmed by (1) the absence of clinical symptoms traditionally attributed to neuroendocrine secretagogues and (2) the lack of gastroenteropancreatic peptide serum levels.

CONCLUSIONS

Two of these three cases represent another subset of pancreatic neuroendocrine pathology: a nonfunctional cystic neoplasm. Increased clinical awareness, appropriate operation, and better immunohistochemical staining techniques may yield more, heretofore unrecognized, subtypes. These cases reemphasize the need for proper surgical exploration and biopsy of all unexplained pancreatic cystic lesions, particularly if they are multicystic.

Tyrosine hydroxylase indicates cell differentiation of catecholamine biosynthesis in neuroendocrine tumors

The intracellular localization of tyrosine hydroxylase (TH), which is the rate limiting enzyme in catecholamine (CA) biosynthesis, and its activity in various adrenal and other neuroendocrine tumors was studied. TH was strongly localized in adrenal medulla, pheochromocytoma, and paraganglioma, but was scatteredly expressed in neuroblastoma. TH was not detected in adrenocortical tumors, ganglioneuroma, and other neuroendocrine tumors. Neuron specific enolase (NSE) was found in all neuroendocrine tumors, but Grimelius staining showed only the secreting granules of the tumor cells. TH activity was significantly high in pheochromocytoma and paraganglioma as compared with that in normal adrenal gland, whereas TH activity was low in a neuroblastoma and was undetectable in other tumors. These findings indicate that TH correlates well with the biosynthetic function of CA in the tumor cell and, thus, both the immunostaining of TH and the measurement of its activity in adreno-medullary and related tumors may provide some information about the process of cell differentiation in these tumors.

[Combined treatment of metastatic endocrine tumors of the gastrointestinal tract with octreotide and interferon-alpha]

14 patients with metastatic endocrine gastro-entero-pancreatic carcinoma (6 patients with Carcinoid-syndrome, 3 with gastrinoma and 5 with non-functioning tumor) have been treated with Octreotide 3 x 200 micrograms/die plus Interferon-Alpha 3 x 5 Mio U/week after documented tumor progression during preceding Octreotide-monotherapy. 6 out of 14 patients responded favourable to the treatment: one patient with partial regression and 5 patients with stillstand of tumor growth. In only one patient initial tumor stillstand for 6 months was followed by tumor progression whereas in five patients a beneficial effect on tumor growth could be documented up to 34 months. Inhibition of tumor growth and tumor progression was not necessarily paralleled by respective changes in peripheral hormone levels. These results should initiate a controlled prospective study to prove the hypothesis that in patients with metastasized endocrine gastro-entero-pancreatic tumors the combination of Octreotide and Interferon-Alpha is superior to monotherapy with Octreotide or Interferon-Alpha and to identify those patients who respond to this combined therapy.

[Morphological diagnosis and classification of lung tumors]

Morphologic examination is mandatory for distinction between benign and malignant pulmonary lesions and separation of primary tumors from metastatic disease. Tumors are classified as to their type and grade by histology and/or cytology. Differences in behavior and response to treatment make the distinction between small cell carcinoma [SCLC] and non-small cell carcinoma [NSCLS] the single most important decision the pathologist must make when examining a lung tumor. The considerable cellular heterogeneity of bronchogenic carcinoma may be the source of problems and pitfalls in morphologic classification of these tumors, discussed in this review together with the concept of neuroendocrine neoplasms.

[A benign neuroendocrine tumor of the lung: study on the origin of the so-called sclerosing hemangioma of the lung]

31 cases of the so-called sclerosing hemangiomas of the lung were studied by light microscope, immunohistochemical and electron microscopy. This tumor is benign and has 3 histologic patterns: papillary, hemangioma-like and solid type. Characteristic morphology being uniform round tumor cells, lying within the stroma in different patterns and regarded as the major component of sclerosing hemangioma, expressing neuroendocrine markers which include chromagranin A, neuron-specific enolase, ACTH, growth hormone, calcitonin and gastrin. Only a few tumor cells were positive for epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), all the tumor cells were negative for keratin (Polyclonal, Z622) stain. However, in contrast to the round tumor cells, the cells lining papillary projections or cystic spaces, which presented as normal or hyperplastic alveolar cells, stained positive for keratin, EMA and CEA but negative for neuroendocrine markers. Both the surface cells and tumor cells were negative for Factor VIII-related antigen and alpha 1-AT. Therefore, pulmonary sclerosing hemangioma was regarded to be a benign tumor originating from the neuroendocrine cells of the lung and we suggest that it be renamed as benign neuroendocrine tumor of the lung (LBNET). This viewpoint has not been previously reported in the literature.

[Expression and co-expression of cellular oncogenes in the course of tumor progression in neuroendocrine lung tumors]

The tumours studied were as follows: benign carcinoids, well differentiated carcinomas (atypical carcinoids) and poorly differentiated tumours (small-cell carcinoma with neuroendocrine differentiation). Oncoproteins c-myc, c-fos, c-jun, L-myc, c-sis, c-ras, c-src, c-ets-1, c-met were studied immunohistochemically in the material obtained from 25 patients during the operations. A higher expression of c-fos, c-jun, c-ets-1 and c-met is observed at early stages of progression and that of c-myc and L-myc at later stages. Enhancement of c-myc and L-myc expression correlated with the invasiveness and lymphogenic metastasizing. Co-expression and negative correlation between some oncogenes are established. The data obtained may be used for prognosis and therapy.

Endocrine tumors of the gastrointestinal tract

Endocrine tumors of the gastrointestinal tract are among the most interesting and heterogeneous of human malignancies. Presenting in highly variable fashions, carcinoid tumors and pancreatic endocrine tumors share natural histories that may range from the serendipitously found, easily cured appendiceal carcinoid to the highly malignant pancreatic islet cell tumors associated with unique endocrine syndromes. The heterogeneity and the relative rarity of these tumors hinder both basic and clinical research. However, new concepts of tumor biology, diagnosis, and treatment are emerging, which will lead to better understanding of the behavior of these tumors and, ultimately, to better treatment of the individual patient.

Reactivity of lung tumors with lung-derived and non-lung-derived monoclonal antibodies

The reactivity of 74 lung-derived monoclonal antibodies (MAbs) provided by the Third International Workshop on Lung Tumor Antigens and of 41 non-lung-derived commercially available MAbs against sections of 15 lung tumors of various histologic types was investigated by immunohistochemistry. Three MAbs with specificity for human neural-cell adhesion molecule (H-NCAM) and 3 MAbs with specificity for small-cell lung carcinoma (SCLC) were able to distinguish between neuro-endocrine (NE) and non-NE tumors. Fifteen MAbs stained non-small-cell carcinomas (NSCLC) but not SCLC. Neuron-specific enolase (NSE) stained all NE tumors but also some of the non-NE tumors. Two MAbs showed specificity for mesotheliomas. Carcino-embryonic MAb strongly stained all SCLC and NSCLC. Among MAbs with lymphoid-cell specificities, Leu 7 (CD57) stained SCLC, but not NSCLC. LN2 (CD45R), LN3 (HLA-DR), Leu 22 (CD43) and BLA 36 reacted with NSCLC and were non-reactive with SCLC. Some of the lung-derived MAbs showed immune staining of lymphoma and melanoma.

[Contributions and limitations of transcutaneous ultrasonography in the preoperative evaluation for hepatic resections]

From October 1990 to January 1992, 36 patients were operated in order to perform an hepatectomy for hepatic metastases (n = 33) or primary malignant tumors (= 3). The authors evaluated the reliability of preoperative ultrasonography (US) by comparing US data to intraoperative findings without consideration of others preoperative examinations. Preoperative US detected 65 out the 78 nodules founded intra-operatively; 13 nodules (4 to 30 mm) and a micronodular dissemination were not detected (sensitivity 82% for the whole lesions). Probable causes of false negative cases (size, location and echogenicity of the nodules) are discussed. Sixty three out of the 65 nodules detected were correctly located in the hepatic segmentation by preoperative US. Hepatectomy was performed in 30 of the 36 patients (84%). The resection previously planned by preoperative US was realized in 24 patients, 5 hepatic resections (14%) had to be enlarged and one completed by a lymphadenectomy; in 6 cases (16.5%) the hepatectomy was not possible because of intraoperative findings of lesions previously not detected by preoperative examinations including US (3 with not removable hepatic nodules, 3 with lymph nodes metastases). This study confirms the reliability of US for anatomical location of hepatic lesions. US sensitivity for the detection is satisfactory. However the number of nodules was underestimated in one third of the patients. The hepatic resection previously planned was effectively realized in only 67% of the cases, in one case out of 6, the resection had to be enlarged and in one case out of 6, the resection was not possible.

Characterisation of neuroendocrine tumors in transgenic mice

Transgenic mice carrying hybrid constructs made by hormone gene promoters attached to viral oncogene sequences proved extremely valuable to investigate the regulatory potency of hormone gene 5' regions. These transgenic mice heritably develop tumors from hormone-producing cells and offer excellent opportunities for studying oncogenesis in the neuroendocrine system. Here the histology of neuroendocrine tumors of three transgenic mice strains (AVP/SV40; RIP1Tag2/RIP2PyST1; GLU2/Tag) is reviewed, preneoplastic lesions are described and tumor development morphology is reconstructed. Transgenic mice experiments provide unique tools for expanding our knowledge of neuroendocrine tumor histogenesis.

NCAM and lung cancer

The presence of the neural cell adhesion molecule, NCAM, is indicative for a poor prognosis in lung-cancer patients. Using MAb 735, we have investigated the expression of polysialic acid, PSA, on NCAM in a spectrum of neuro-endocrine lung tumors, ranging from the slowly growing typical carcinoids via the atypical carcinoids with clinically unpredictable behavior to the highly aggressive small-cell lung carcinomas. Our immunohistochemical findings indicate a significant association between the presence of PSA on the tumor cells and an aggressive and immature sub-type of the tumor. This might be related to impairment of cell-cell and cell-matrix interactions by the presence of PSA, as we demonstrated in vitro, since detachment is one of the first steps in the metastatic process. The NCAM-MAb 123C3 used in these studies appeared extremely useful in immunoscintigraphy and immunotherapy of SCLC xenografts in nude mice, and for immunoscintigraphy of a SCLC patient. This may be explained by internalization of the 123C3 antibody, which we demonstrated in vitro. 123C3 is the only Cluster-I SCLC MAb studied thus far that becomes internalized.