S100A10, S100A6, S100A4 and S100A2 are all members of the S100 family of calcium-binding proteins and are located in a cluster on 1q21.3; a region that has been shown to have both high level gains (1q21–q31; Ward et al, 2001) and an association with tumour recurrence in ependymoma (1q21.1–q23.1; Mendrzyk et al, 2006). This evidence concerns the gene S100A6 and ependymoma.