Evidence is accumulating implicating a role for integrins in the pathogenesis of cancer, a disease in which alterations in cellular growth, differentiation, and adhesive characteristics are defining features. In the present report we studied a panel of 8 human astrocytoma cell lines for their expression of integrin subunits by RT-PCR, and of integrin heterodimers by immunoprecipitation analyses. The functionality of integrin heterodimers was assessed using cell attachment assays to plastic or single matrix substrates. Downstream effects of integrin activation were studied by western blot analyses of FAK expression in human astrocytoma cell lines growing on plastic and on a fibronectin matrix, and in 13 primary human brain tumor specimens of varying histopathological grade. Furthermore, we studied tyrosine phosphorylation of FAK in astrocytoma cells growing on plastic versus fibronectin. Finally, we analyzed the effects of intermediate filament gene transfer on FAK phosphorylation in SF-126 astrocytoma cells. Our data show that astrocytoma cell lines express various integrin subunits by RT-PCR, and heterodimers by immunoprecipitation analyses. The beta1 and alphav integrin subunits were expressed by all astrocytoma cell lines. The alpha3 subunit was expressed by all cell lines except SF-188. By immunoprecipitation, the fibronectin receptor (alpha5beta1 integrin heterodimer) and the vitronectin receptor (alphavbeta3) were identified in several cell lines. Astrocytoma cell attachment studies to human matrix proteins suggested that these integrin heterodimers were functional. Using confocal laser microscopy, we showed that FAK was colocalized to actin stress fibers at sites of focal adhesion complexes. By western blot, FAK was variably but quite ubiquitously expressed in human astrocytoma cell lines, and in several primary human astrocytoma specimens. When U373 and U87 MG astrocytoma cells bind to a fibronectin matrix, FAK is phosphorylated. GFAP-transfected SF-126 human astrocytoma cells were shown to overexpress the phosphorylated form of FAK only when these cells were placed on a fibronectin matrix. This result is of interest because it suggests that manipulations of the astrocytoma cytoskeleton per se can bring about potential signaling changes that channel through integrins and focal adhesion sites leading to activation of key kinases such as FAK.

A 9-month-old male presented to hospital with signs and symptoms of raised intracranial pressure. A CT scan showed obstructive hydrocephalus from a large pineal region mass lesion into which an intratumoral hemorrhage had occurred. A posterior fossa craniectomy and subtotal excision of the mass lesion were performed. By histopathology, the lesion was a malignant rhabdoid tumour (MRT). Despite surgery and chemotherapy, the tumour grew inexorably, and the patient died four months after the initial diagnosis. MRT is a rare and highly invasive neoplasm which infrequently arises from the central nervous system. This is the first documented case of a MRT arising from the pineal region. The clinical, radiographic, and pathological features of the MRT in this patient are presented.Resume: Tumeur rhaboi'de maligne de la region pineale. Un bebe de sexe masculin, age' de 9 mois, a &X& admis a l'hopital parce qu'il pr6sentait des signes et des symptomes d'hypertension intracriinienne. Un CT scan a montre' une hydrocephalic obstructive due & une grosse masse situ6e dans la region pindale dans laquelle une hdmorragie intratumorale s'6tait produite. Par voie de la fosse postdrieure, on a precede' a une excision subtotale de la masse. A l'histopathologie, la lfision etait une tumeur rhabdoi'de maligne (TRM). La tumeur a progress^ inexorablement, malgre' la chirurgie et la chimiotherapie, et le patient est decfid6 quatre mois apres le diagnostic initial. La TRM est une n£oplasie rare et tres invasive originant peu fr6quemment du systeme nerveux central. Ceci constitue le premier cas document^ d'une TRM originant de la region pineale. Nous prSsentons les caracteiistiques cliniques, radiologiques et pathologiques de la TRM chez ce patient.Can. J. Neurol. Sci. 1994; 21: 273-277 The malignant rhabdoid tumour (MRT) is an uncommon neoplasm of early childhood. MRT is clinically characterized by an early age of onset and a poor prognosis.'-2 The high mortality associated with MRT results from its highly invasive and metastatic potential. The majority of MRTs occur in the infant kidney. MRT accounts for 2% of all childhood renal neoplasms. 3 Extra-renal MRTs are much less common than renal MRTs. To date, only 13 cases of MRTs of the central nervous system (CNS) have been reported. 4 " 13 We present the 14th documented case of a primary rhabdoid tumour of the CNS which satisfies the clinicopathological criteria for classification as a primary MRT. To our knowledge, this is the first reported case of a MRT arising from the pineal region. The clinical, radiographic and pathological findings of this rare but recently recognized CNS tumour are presented. CASE REPORTA 9-month-old male infant presented to hospital with a 5 day history of vomiting and irritability. On examination, he was clinically dehydrated, lethargic and demonstrated a "sun-setting" gaze paresis. His head circumference measured 49 cm (> 98th percentile) and his anterior fontanelle was full and tense. A CT scan showed enlarged ventricles and a large, hyperdense ma...