Neuropeptide Y secretion from a malignant extraadrenal retroperitoneal paraganglioma

Potential Biomarkers of Metastasizing Paragangliomas and Pheochromocytomas

Paragangliomas and pheochromocytomas (PPGLs) are rare neuroendocrine tumors originating from paraganglionic tissue in many sites of the body. Most PPGLs are characterized by nonaggressive behavior but all of them have the potential to metastasize. PPGLs represent a great diagnostic dilemma as it is difficult to recognize tumors that are likely to be metastasizing; criteria of malignancy can be found both in benign and metastatic forms. This review aims to analyze the current knowledge of the nature of metastasizing PPGLs paying particular attention to head and neck paragangliomas (HNPGLs). Potential predictors of the malignancy risk for PPGLs were summarized and discussed. These data may also help in the development of diagnostic and prognostic strategies, as well as in the identification of novel potential therapeutic targets for patients with PPGLs.

Differential effects of neuropeptide Y on the growth and vascularization of neural crest-derived tumors

Neuropeptide Y (NPY) is a sympathetic neurotransmitter recently found to be potently angiogenic and growth promoting for endothelial, vascular smooth muscle and neuronal cells. NPY and its cognate receptors, Y1, Y2 and Y5, are expressed in neural crest-derived tumors; however, their role in regulation of growth is unknown. The effect of NPY on the growth and vascularization of neuroendocrine tumors was tested using three types of cells: neuroblastoma, pheochromocytoma, and Ewing's sarcoma family of tumors (ESFT). The tumors varied in expression of NPY receptors, which was linked to differential functions of the peptide. NPY stimulated proliferation of neuroblastoma cells via Y2/Y5Rs and inhibited ESFT cell growth by Y1/Y5-mediated apoptosis. In both tumor types, NPY receptor antagonists altered basal growth levels, indicating a regulatory role of autocrine NPY. In addition, the peptide released from the tumor cells stimulated endothelial cell proliferation, which suggests its paracrine angiogenic effects. In nude mice xenografts, exogenous NPY stimulated growth of neuroblastoma tumors, whereas it increased apoptosis and reduced growth of ESFT. However, in both tumors, NPY treatment led to an increase in tumor vascularization. Taken together, this is the first report of NPY being a growth-regulatory factor for neuroendocrine tumors, acting both by autocrine activation of tumor cell proliferation or apoptosis and by angiogenesis. NPY and its receptors may become targets for novel approaches in the treatment of these diseases, directed against both tumor cell proliferation and angiogenesis.

Unusual cause of early preeclampsia: bladder paraganglioma

Ten to twenty percent of paragangliomas occur at extra-adrenal locations and less than 1% are at the urinary bladder. The most common presenting symptom of bladder paraganglioma is hypertensive attacks precipitated by micturition and hematuria. Paraganglioma of the urinary bladder occurring at pregnancy is extremely rare. We present a case of bladder paraganglioma as an unusual cause of early preeclampsia. After termination of the pregnancy, surgical resection was performed and the histopathologic diagnosis of paraganglioma confirmed. At 24 months of follow-up the patient felt well and was normotensive without any foci of paraganglioma. Although rare, paraganglioma must be considered in the differential diagnosis of early preeclampsia.

The role of tumor necrosis factor-alpha in the pathogenesis of anorexia and bulimia nervosa, cancer cachexia and obesity

In this paper a new immunological model of anorexia and bulimia nervosa will be presented in which the inflammatory cytokines are conceived as the fundamental regulators of body metabolism. This conception differs from the conventional view in which the inflammatory cytokines are perceived primarily as peptide molecules utilized by the immune system to control infection, inflammation and tissue or neuronal damage. Given that the inflammatory cytokines are also fundamental regulators of body metabolism, when they become dysregulated they create physiological chaos which results in the development of a number of autoimmune, metabolic and psychiatric disorders. In this proposed immunological model of anorexia and bulimia nervosa, elevated tumor necrosis factor-alpha features as the primary cause of these conditions. Pathophysiological parallels are drawn between anorexia nervosa and cancer cachexia in terms of the causal role the cytokines, neuropeptides and neurotransmitters play in the manifestation of shared symptoms. These shared symptoms include elevated tumour necrosis factor-alpha, down-regulated interleukin-2 and interleukin-4 and depletion of lean body mass. Furthermore, the following neuropeptides are dysregulated in both anorexia nervosa and cancer cachexia: vasoactive intestinal peptide, cholecystokinin, corticotropin-releasing factor, neuropeptide Y, peptide YY and beta-endorphin. In addition, in anorexia and bulimia nervosa, secretion of the neurotransmitter serotonin is inhibited while norepinephrine is enhanced. It will be argued that the causal interplay between the cytokines, neuropeptides and neurotransmitters initiates a cascade of biochemical events which may result in either anorexia or bulimia nervosa, or cancer cachexia. The extent to which these inflammatory cytokines, neuropeptides and neurotransmitters are causally efficacious in the pathogenesis of other autoimmune disorders, such as diabetes mellitus and rheumatoid arthritis, will also be addressed.

A 15-year experience with chemotherapy of patients with paraganglioma

BACKGROUND

Paraganglioma is a rare tumor thought to arise from the neuroectodermally derived paraganglionic cells that are dispersed widely along the autonomic ganglia. They can metastasize to bones, lymph nodes, and lungs and occasionally present with spinal cord compression. Up to 60% of retroperitoneal paragangliomas can be functional, with symptoms and signs of norepinephrine overproduction.

METHOD

A 15-year experience with chemotherapy of patients with paraganglioma was reviewed. The patient population was identified through a search of the data-base maintained by the Departments of Melanoma-Sarcoma Medical Oncology and Pathology at the University of Texas M.D. Anderson Cancer Center (Houston, TX).

RESULTS

Thirteen of 84 patients with histologically confirmed diagnosis of paraganglioma were treated with chemotherapy. The median age was 42 years (range, 25-67 years); there were eight males and five females. Primary sites included retroperitoneum (seven patients), head and neck (two patients), pelvis, bladder, mediastinum, and paravertebral (one patient each). Twelve patients received chemotherapy for metastatic disease, and 1 had an unresectable mediastinal primary tumor. Eleven patients received cyclophosphamide, doxorubicin, and DTIC/dacarbazine (CyADIC)/cyclophosphamide, vincristine, doxorubicin and DTIC/dacarbazine (CyVADIC), and 2 received doxorubicin and dacarbazine (ADIC) at standard doses for a median of 4 cycles (range, 2-12 cycles). Six of 13 patients achieved an objective partial remission (response rate = 46%, 95% confidence interval = 19-73%); 6 other patients had stable disease, and one developed progressive disease. At the time of last follow-up, eight patients were alive with disease, four died, and one patient was alive with no evidence of disease. The median follow-up from diagnosis was 45 months (range, 12-300 months).

CONCLUSION

Cyclophosphamide, doxorubicin, dacarbazine chemotherapy is active in the treatment of patients with paraganglioma.

Multiple neuropeptide immunoreactivities in a renin-producing human paraganglioma

BACKGROUND

A case of a renin-producing paraganglioma of adrenal origin with metastases to the retroperitoneal area, paravaginal area, and the ovary is reported with immunohistochemical findings indicating expression of multiple neuropeptide immunoreactivities. The patient was 23 years old at the time of diagnosis, and died from metastatic spread of the tumor 7 years later.

METHODS

Tumor tissue was examined by light microscopy, indirect immunohistochemistry, and electron microscopy.

RESULTS

The tumor tissue investigated contained several cells exhibiting opioid peptide-like immunoreactivities (i.e., enkephalin and dynorphin-like immunoreactivity [LI]). A lower number of cells displayed neuropeptide Y-, galanin-, somatostatin-, neurotensin-, substance P-, peptide histidine-isoleucine-, cholecystokinin-, renin-, and calbindin-LI.

CONCLUSION

To the authors' knowledge, galanin, dynorphin, peptide histidine-isoleucine, cholecystokinin, and calbindin have not been reported previously to occur in paraganglioma, and renin has been reported to occur very rarely. A review of recent literature suggest that enkephalin-, neuropeptide Y-, and somatostatin-like immunoreactivities may be useful as diagnostic markers for paragangliomas.