However, histological sections of C6 glioma tumours stained with the endothelial-specific GSL lectin have demonstrated that the number of blood vessels per field (×400) in C6 tumours derived from mice treated with TR (25 μg) was reduced by 33% compared with non-treated control (10.8±0.41 s.e. This evidence concerns the gene CTSA and central nervous system cancer.