Human breast tumors consist of phenotypically diverse cells and studies indicate that a small subset of cells termed cancer stem cells are the only cells in a tumor capable of initiating and maintaining cancer growth. A subpopulation with a CD44+/CD24– phenotype has been isolated from breast tumors and was found to possess highly tumorigenic characteristics. These CD44+/CD24– cells were able to differentiate into phenotypically diverse nontumorigenic cells, resembling the composition of the original tumor. Further molecular and phenotypic analysis of CD24+ and CD44+ cells from breast tumors revealed distinct gene expression, epigenetic and genetic profiles that may have clinical relevance. There is also heterogeneity between tumors, illustrated by stratification into various subtypes based on gene expression profiles or histopathological features.
Our research focus on characterizing the putative cancer stem cells in breast cancer with respect to phenotype, genotype and function in order to identify new markers of stemness and examine the importance of the stem-cell like population in proliferation, tumorigenicity and chemoresistance. We also investigate the correlation between putative cancer stem cells and biological or clinical characteristics in different subtypes of breast cancer to determine any association of this population to tumour progression and metastatic behaviour.