Breast cancer is classified into four subtypes in clinic as ER+ (luminal A or luminal B, usually PR+/− Her2−),overexpressed Her2 (Her2+, usually ER−PR−), negative for ER, PR, and Her2 (ER−PR−Her2−, mostly basal-like) i.e. Triple negative, and normal-like. In breast cancer, showed a small subset of population (CD44+ CD24low/-) that are highly tumorigenic. These cells are termed as Cancer-stem cells (CSC). Owing to heterogeneity nature of these cells, it will be crucial to identify the homogenous population that perhaps could be beneficial in targeted cancer therapy. In this project, the novel cancer stem cells will be isolated and characterized from the human breast cancer cell lines.