SP1 and breast carcinoma: Genes that are induced by PR/Sp1 have primarily been observed in T47D breast cancer cells that overexpress PR and include p21/p27 [62,63], EGFR [59], PRL receptor [64] and MKP1 [65] that are activated by PR/Sp1; HSPB8 is induced via PRE-(N)X-GC sequence and also includes cyclin D1 as part of the complex [66].