Clinical implication of estrogen-related receptor (ERR) expression in uterine endometrial cancers

Estrogen receptor (ER)α and ERβ mRNAs levels decreased with clinical stage, myometrial invasion and dedifferentiation. On the other hand, ERRα mRNA levels and histoscores increased with clinical stage and myometrial invasion, regardless of dedifferentiation. ERRα can bind to the steroid receptor coactivator family without any ligands, and drive transcription activity of the target genes. The competitive interaction of ERRα/ER expression associated with the use of common cofactors during loosing estrogen dependency might cause their expression manner. The up-regulation of ERRα might be related to tumor growth and advancement in uterine endometrial cancers. It is speculated that ERRα is a candidate for prognostic factors in uterine endometrial cancer, although ERRs are not directly related to growth of uterine endometrial cancer.