Abstract: The present disclosure relates to a method for predicting prognosis of cancer and a composition thereof. More specifically, the present disclosure relates to a composition and a method for predicting prognosis of breast cancer and predicting the treatment effect of chemotherapy. The present disclosure provides gene expression information useful for predicting whether a cancer patient is more likely to respond favorably to treatment in chemotherapy.

Abstract: Provided is a multipotent cancer stem cell line derived from breast-cancer tissue and expressing a breast cancer stem cell marker. Also provided is a method for producing a multipotent cancer stem cell line, including (1) isolation of breast-cancer cells from previously extracted breast cancer tissue, (2) primary culture of the isolated breast cancer cells in a suspended state in a medium for suspension culture, (3) recovery of the cells in the suspended state from the primary culture, and (4) production of a multipotent cancer stem cell line by subculturing the recovered cells a predetermined number of times or more in a suspended state in the medium for suspension culture.