The Reporting Recommendations for Tumor Marker Prognostic Studies guidelines [11]. The primary breast tumors were from patients with detailed clinical follow-up as previously described [12-14]. ER protein status was determined by routine ligand-binding assays or enzyme immunoassays [15], and ESR1, ESR2, and PGR mRNA status wasTissue processing, RNA isolation, cDNA synthesis, and quantitative RT-PC