Description
Breast cancer is a curable disease if it is diagnosed at an early stage. However, only little options are left once the tumor is metastasized to distant organs, and more than 90% of breast cancer death is attributed to metastatic disease. The process of metastasis is highly complex and involves many steps for successful colonization of tumor cells at a target organ. According to the cancer stem cell (CSC) theory, which still remains a hypothesis, these metastatic cells must have stem cell-like capability for their self-renewal in addition to their invasive ability. Therefore, it has been predicted that a metastatic stem cell, which is distinct from a cancer stem cell, must exist in the primary tumor mass. To identify genes that are involved in metastasis of CSCs, we isolated CSC populations from a well-established model cell line of breast cancer, MDA-MB231, and that of highly metastatic variants, 231BoM-1833 and 231BrM-2a, using CD24, CD44 and EpCAM (ESA), which have been identified as surface markers for CSCs in breast cancers. Overall yield of CSCs from these cells ranged from 2% to 4%. We then performed global expression profile analysis for these CSCs using the Affymetrix Human Gene 1.0ST array.