Given some similarity between triple negative breast cancers and letrozole resistant breast cancers (i.e., both are estrogen-independent and progesterone receptor negative) [9], we sought to explore the inhibitory properties of glyceollins in a letrozole resistant cell line model (LTLT-Ca cells) and demonstrate for the first time the ability of glyceollins to reverse EMT. The gene discussed is PGR; the disease is triple-negative breast carcinoma.