About 65% of these are also ‘PR-positive’ (Progesterone receptor).Tumours that are ER/PR-positive are much more likely to respond to hormone therapy than tumours that are ER/PR-negative.Triple negative breast cancer (TNBC) lacks all three receptors i.e.ER, PR, and Her2. The gene discussed is ESR1; the disease is triple-negative breast carcinoma.