Department of Anatomy and A.P., Faculty of Veterinary Sciences, University of Santiago de Compostela, Spain.

Adrenomedullin (ADM) is a novel peptide originally identified in extracts of human pheochromocytoma. It is produced by several tissues, including the pituitary gland. The presence of ADM has been immunohistochemically demonstrated in pathologic pituitary glands, but no systematic study of ADM expression in human pituitary adenomas has been reported. Thus, we investigated ADM immunoexpression in 88 various hormone-secreting and clinically nonfunctioning pituitary adenoma types as well as 30 nontumoral adenohypophyses. Furthermore, ADM immunoreactivity was assessed on a 0 to +3 scale in all samples. We found strong immunoreativity for ADM in normal gonadotrophs also expressing FSH and LH whereas in the other adenohypophysial cell types expression of ADM was mild. Results showed that normal adenohypophyses were strongly immunopositive for ADM (2.18+/-0.11). Our findings demonstrate that ADM expression in the anterior pituitary is diminished in tumors as compared to the normal gland. The physiologic function of ADM is unknown, but it could act as a paracrine or autocrine factor in the adenohypophysis.

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Operative Unit of Neurosurgery, Regional General Hospital, Via Bohler 5, 39100 Bolzano, Italy.

Primary central nervous system lymphoma (PCNSL) is an extranodal non-Hodgkin lymphoma arising from and confined to the neuraxis. It represents about 3-4% of all primitive brain neoplasms and is mainly located in deep supratentorial regions. A ventricular involvement is quite frequent, but in the vast majority of cases it is secondary to an extension from a subependymal location. Amongst the primary ventricular forms occasionally reported, a choroid plexus origin is extremely rare; to date, only three cases have been described in the English literature. We report the case of a 71-year-old left-handed woman admitted to our department after a progressive 2-week history of confusion, motor speech disturbances and left hemiparesis. A brain MRI scan displayed an intraventricular lesion located in the right atrium, about 2.5cm in its major axis, homogeneously enhancing after gadolinium administration, surrounded by edema in the homolateral deep hemispheric region; the main diagnostic hypothesis was meningioma. She underwent a parieto-occipital craniotomy and a navigation-assisted posterior parietal transcortical approach, achieving complete removal of the intraventricular lesion originating from the choroid plexus. The histological diagnosis was of high-grade diffuse large B-cell lymphoma. Both an MRI scan of the entire craniospinal axis and a thoracic and abdominal CT scan showed no other neoplastic lesions; a bone marrow biopsy was normal; a final diagnosis of primary central nervous system lymphoma was made. CSF cytological analysis did not show any signs of lymphoma dissemination. Adjuvant chemotherapy with methotrexate was administered, and at the last follow-up (26 months) our patient is clinically and radiologically disease-free. Primary choroid plexus lymphoma is a very rare tumor that should be included in the differential diagnosis of intraventricular neoplasms. It usually occurs in the lateral ventricles (with a predilection for the atrium) of adult people (>50 years of age), apparently with a male prevalence. Generally, the radiological picture mimics that of a meningioma, despite the fact that meningiomas usually reach a greater volume before clinical onset. Surgery is almost always necessary to obtain an adequate tissue sample and frequently leads to a radical removal of the lesion. Low-grade marginal zone B-cell, T-cell and high-grade diffuse large B-cell (present case) forms have been described. With a proper adjuvant therapy a relatively good outcome is observed.

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Department of Neurology, University of Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany, ludwig.aigner@klinik.uni-regensburg.de.

Mechanisms that regulate neural stem cell activity in the adult brain are tightly coordinated. They provide new neurons and glia in regions associated with high cellular and functional plasticity, after injury, or during neurodegeneration. Because of the proliferative and plastic potential of neural stem cells, they are currently thought to escape their physiological control mechanisms and transform to cancer stem cells. Signals provided by proteins of the transforming growth factor (TGF)-beta family might represent a system by which neural stem cells are controlled under physiological conditions but released from this control after transformation to cancer stem cells. TGF-beta is a multifunctional cytokine involved in various physiological and patho-physiological processes of the brain. It is induced in the adult brain after injury or hypoxia and during neurodegeneration when it modulates and dampens inflammatory responses. After injury, although TGF-beta is neuroprotective, it may limit the self-repair of the brain by inhibiting neural stem cell proliferation. Similar to its effect on neural stem cells, TGF-beta reveals anti-proliferative control on most cell types; however, paradoxically, many brain tumors escape from TGF-beta control. Moreover, brain tumors develop mechanisms that change the anti-proliferative influence of TGF-beta into oncogenic cues, mainly by orchestrating a multitude of TGF-beta-mediated effects upon matrix, migration and invasion, angiogenesis, and, most importantly, immune escape mechanisms. Thus, TGF-beta is involved in tumor progression. This review focuses on TGF-beta and its role in the regulation and control of neural and of brain-cancer stem cells.

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Department of Surgery, Saint Mary’s Health System, 56 Franklin St., Waterbury, CT 06702, USA. home_pimiento@hotmail.com

BACKGROUND: Cancer of unknown primary (CUP) origin is a very aggressive disease with a poor prognosis. Most of the literature reports of CUP are generated from tertiary cancer centers. METHODS: A retrospective chart review of all patients with a diagnosis of CUP was performed between January 1995 and January 2005. Age, gender, diagnostic evaluation, histologic diagnosis, location of metastases, treatment, and survival were recorded. RESULTS: Ninety-one patients met the inclusion criteria. The pathologic diagnoses included adenocarcinoma (42.8%), undifferentiated carcinoma (34.5%), squamous cell carcinoma (9.8%), neuroendocrine cancer (6.5%), sarcoma (3.2%), and nonspecific malignant neoplasm (3.2%). The overall mean survival was 9.2 months (95% confidence interval, 6.1-12.4 mo), and for squamous cell carcinoma was 26.9 months (standard error, 5.7; P = .007). CONCLUSIONS: CUP encompasses a variety of different pathologic entities with an overall dismal 5-year survival. Nonetheless, squamous cell and neuroendocrine CUP are associated with a significantly better early prognosis than the other malignancies.

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Department of Neurology, University of Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany, ludwig.aigner@klinik.uni-regensburg.de.

Mechanisms that regulate neural stem cell activity in the adult brain are tightly coordinated. They provide new neurons and glia in regions associated with high cellular and functional plasticity, after injury, or during neurodegeneration. Because of the proliferative and plastic potential of neural stem cells, they are currently thought to escape their physiological control mechanisms and transform to cancer stem cells. Signals provided by proteins of the transforming growth factor (TGF)-beta family might represent a system by which neural stem cells are controlled under physiological conditions but released from this control after transformation to cancer stem cells. TGF-beta is a multifunctional cytokine involved in various physiological and patho-physiological processes of the brain. It is induced in the adult brain after injury or hypoxia and during neurodegeneration when it modulates and dampens inflammatory responses. After injury, although TGF-beta is neuroprotective, it may limit the self-repair of the brain by inhibiting neural stem cell proliferation. Similar to its effect on neural stem cells, TGF-beta reveals anti-proliferative control on most cell types; however, paradoxically, many brain tumors escape from TGF-beta control. Moreover, brain tumors develop mechanisms that change the anti-proliferative influence of TGF-beta into oncogenic cues, mainly by orchestrating a multitude of TGF-beta-mediated effects upon matrix, migration and invasion, angiogenesis, and, most importantly, immune escape mechanisms. Thus, TGF-beta is involved in tumor progression. This review focuses on TGF-beta and its role in the regulation and control of neural and of brain-cancer stem cells.

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