Human ovarian GCTs are also characterized by frequent focal staining for estrogen receptor alpha (ERα) (Fig. 8; Additional file 6: Figure S5)e which suggests that APC2 deficiency not only increases the frequency of GCTs in mice which also carry a hypomorphic Apc allele, but also results in tumours with a greater histological and molecular similarity to human GCTs. This evidence concerns the gene ESR1 and neoplasm.