Since yeast two-hybrid experiments have shown S100A6 to interact with S100B and co-localise in astrocytoma cells (Deloulme et al, 2000), we investigated the expression of both S100A6 and S100B in serial sections of prostatic adenocarcinoma of various Gleason scores and adjacent benign epithelium. The gene discussed is S100B; the disease is astrocytoma (excluding glioblastoma).