However, most discordance studies initially include all breast cancer patients in their studies (HR‐positive as well as HR‐negative), monitor the conversion to the HR over time, and make a sum of the conversion rates for ER and PR to attain a discordance rate, whereas the biology of the cancers and their treatment may vary considerably between the patients depending on the HR‐status. The gene discussed is ESR1; the disease is breast carcinoma.