The assessment of sTILs at the primary tumor site via light microscopy of haematoxylin and eosin (H&E) stained sections, has been shown to be superior to classical TNM staging in TNBC and HER2-positive breast cancers in predicting outcome3, response to chemotherapy4, anti-HER2 therapy5 and to immunotherapy6. The gene discussed is ERBB2; the disease is neoplasm.