A growing body of evidence suggests that malignant stem cells have a role in the growth, spread, and clinical outcomes of breast cancers. In “Correlation of Breast Cancer Axillary Lymph Node Metastases With Stem Cell Mutations,” Donovan et al1 have built on prior notable works devoted to understanding the behavior of breast cancers. This group of authors previously demonstrated that breast cancer stem cells are distinctively different compared with benign and progenitor stem cells found in normal breast tissue, especially with regard to mutations in genes critical for maintaining normal cellular metabolism and proliferation.2