In Vitro Assays of Breast Cancer Stem Cells.

Aldehyde dehydrogenase and mammosphere assays enable the cost-effective quantification and characterization of cancer stem cells (CSCs) from cancer cell lines as well as cancer tissue. Here we describe the quantification of CSCs in breast cancer cell lines using aldehyde dehydrogenase and mammosphere assays under hypoxic (1% O2 ) and non-hypoxic (20% O2 ) culture conditions. Using this method, a significant enrichment of CSCs compared to bulk populations is observed when breast cancer cells are exposed to 1% O2 for 72 h.