CONICET | Buscador de Institutos y Recursos Humanos

Biosilicification (chalcedony) in human astrocytoma and glioblastoma multiforme from aged patients: possible CA IX role. María Prado Figueroa1, Sandro Casavilca2 1Instituto de Investigación Bioquímica (CONICET - Universidad Nacional del Sur) Bahía Blanca, Argentina 2Departamento de Patología, Instituto de Enfermedades Neoplásicas, Lima, Perú A biogenically produced crystalline mineral phase (i.e. chalcedony) has been observed in electric organs from living electric fish (Prado Figueroa et al., 2005; 2007). Chalcedony (SiO2) was also observed in human brain from aged patients (Prado Figueroa et al., 2006). Chalcedony formation is due to the relationship between pH and oxidation potential (Eh) (Krumbein and Garrels, 1952). Chalcedony is a microcrystalline fibrous form of silica and actually consists of nanoscale intergrowths of quartz and the optically length-slow fibrous silica polymorph moganite (Heaney et al., 1994). Glioblastoma is the most aggressive type of primary brain tumor and it involves overexpression of the enzyme carbonic anhidrase IX (CA IX). From these evidences, we decided to document the presence of chalcedony in human astrocytoma II and glioblastoma multiforme from autopsy derived and also biopsy. In those sections, naturally occurring fluorescent mineral was observed by confocal laser scanning microscopy. Our data showed that there is a green fluorescent chalcedony in astrocytoma II with a crystalline mineral phase. In glioblastoma, green fluorescent chalcedony appeared mostly as a partially polymerized fluid that is infiltrating the tissue. CA IX is involved in physiological pH regulation and may be in the depolymerization of silica in the human brain.