Expression of nuclear receptor coregulators in ovarian stromal and epithelial tumours

Granulosa cell tumours of the ovary (GCT) exhibit high expression of estrogen receptor β (ERβ). A role for estrogen receptors in these tumours may depend on altered co-activator expression. This study examines the expression of the co-activators SRC-1a/e, SRC-2, SRC-3, SRA, and the corepressors NCoR and SMRT in GCT, epithelial ovarian tumours and normal ovary. No significant difference in the expression of SRC-1, SRC-2, SRC-3 or NCoR and SMRT was found. In particular, there was no correlation of co-activator expression with ERβ expression. There was a significant upregulation in the expression of the novel RNA co-activator SRA in the serous tumours compared with the other tumour types and normal ovary. The findings suggest that ERβ may require co-activators, other than members of the SRC family for the modulation of transcription in GCT.