Four of these populations were composed of cancer cells: Cancer LumA (predominantly Estrogen Receptor (ER+) clinical subtype, 98.9%), Cancer LumB (mainly ER+ clinical subtype, 94.5%), Basal (primarily triple‐negative breast cancer (TNBC) clinical subtype, 96.8%), and Cancer Her2 (present across clinical subtypes, comprising 8.8% ER+, 36.1% HER2+, and 55.1% TNBC). The gene discussed is ESR1; the disease is cancer.