CD44 and neoplasm: To determine if monolayer paediatric brain tumour cells maintained their original phenotype in vitro, we used immunofluorecent labelling to investigate the expression of a panel of neural (nestin, nf-200, β-III-tubulin and GFAP) and putative tumour progenitor/stem cell markers (CD15, CD29, CD44 and CD133) in subsets of tumour monolayer cultures.