Breast cancer stem cells and epithelial to mesenchymal transition, their putative role in tumor initiation, propagation, and metastasis

Breast cancer stem cells (CSC) are small subset of tumor cells within the tumor, possessing distinct immunological phenotype; they initiate the tumor and sustain tumor growth. Epithelial to mesenchymal transition (EMT) is the loss of epithelial differentiation and gained the mesenchymal properties among some of tumor cells. Acquisition of mesenchymal phenotype allows these cells to infiltrate surrounding tissue, which ultimately enhance tumor propagation and progression. EMT occurrence is always co-existent with CSC subsistence. EMT induced by various factors is rich source of cancer stem like cells suggesting a possible biological similarity between CSC and EMT phenotypic cells. The inhibition of EMT occurrence and CSC elimination may have significant effect on cancer prognosis, which could suggest that these cells will be a target for cancer therapeutics. Prospective identification of new molecules and markers for these tumorigenic cells will facilitate the invention of new agents to eliminate cancers.