Isolation and characterization of human breast tumor stem cells

Objective: To isolate and culture human breast cancer stem cells, and characterize their biological properties in vitro.

Methods: Fresh tumor tissues of breast cancer patients were collected from surgical rooms. The tissue samples were mechanically sheared and enzyme-digested to get single cell suspensions. Cancer cell surface antigens were analyzed by flow cytometry, and cell growth curve was established by MTT assay; Real-time quantitative PCR (qPCR) was employed to detect the expressions of stem cell-specific genes Sox2 and Nanog in the cancer cells; Immunofluorescence staining was performed to examine the expressions of breast cancer-specific proteins Bcl-2 and progesterone receptor (PR).

Results: Human breast cancer stem cells grew in the form of spheres. These stem cells had a CD44(+);/CD24(-); phenotype as characterized by flow cytometry, expressed high levels of Sox2 and Nanog genes, and were positive for Bcl-2 and PR.

Conclusions: Human breast tumors contain CD44(+);/CD24(-); cancer stem cells which are capable of self-renewal and proliferation, and can be long-term cultured and expanded in vitro.