NR2F1 and breast carcinoma: Because 11a activated PNR-related nuclear receptors COUP-TFI and COUP-TFII in the DR2 luciferase assay at the relatively low concentration of 30 nM (Figure 1) and only COUP-TFII could be detected in all breast cancer cell lines [40], we examined whether 11a could alter the expression of COUP-TFII downstream target genes in MCF7 and T47D, two ERα positive breast cancer cell lines.