A new cell line, CB109, has been established from a human glioblastoma multiforme. The cytoskeleton was positive for glial fibrillary acidic protein, vimentin and fibronectin. Hyaluronan (HA) and the HA-binding protein hyaluronectin (HN) were expressed in the cell cytoplasm and in the extracellular matrix of spheroids and plated cells. Hyaluronidase did not prevent spheroid formation suggesting that HA was not involved in the cell-cell adhesion. HA precoating prevented cell adherence to the plates and favoured spheroid formation. HA was secreted in relatively large amounts into the culture medium. High performance liquid chromatography demonstrated that HA was in the high molecular weight form. The rate of HN secretion by cells was very low. Basic fibroblast growth factor significantly increased the proliferation in vitro and tumour growth after grafting into nude mice. The epidermal growth factor receptor was not expressed on cultivated CB109 cells. Cytogenetic analysis showed polysomy 7, structural rearrangement of chromosome 10 short arm and a translocation 13q13-q14 without detectable alteration of the RB gene.