The characteristics most strongly associated with predominantly high-grade tumours versus predominantly low/mid-grade tumours were gains of chromosome arms 3q (whole arm 3q, encompassing the SOX2 and TERC genes) and 12p (whole arm 12p, encompassing the KRAS gene, consistent with a previous report6), both of which were often seen as loss/LOH in predominantly low/mid-grade tumours (Fig. 1f, Extended Data Fig. 2c-d). This evidence concerns the gene KRAS and neoplasm.