If the highest preponderance of ALDH-expressing E-CSCs occurs in the HER2e/cHER2+ and luminal B/cHER2+ BC subtypes and not in the luminal A/cHER2+ subtype, this model could also explain why a minority of patients with cHER2+ BC have an excellent prognosis even in the absence of treatment [83, 84]. The gene discussed is LDHA; the disease is breast cancer.