Breast Cancer Stem Cells; Signaling Pathways and Therapeutics

The most important evidence for the existence of a heterogeneous population of cancer stemcells (CSCs) responsible for the initiation and maintenance of cancer has been characterizedfor several tumors in these several years. The most important characteristics of stem cells arethe capacity for self-renewal and differentiation and also the regulation of the balancebetween self-renewal and differentiation. They function in initiation, maintenance, growth,and metastasis of tumors and demonstrate slow cycling and indefinite ability to renewthemselves. CSCs can proliferate limitlessly and are more resistant to chemotherapy andapoptosis than somatic cancer cells. CSCs are tumorigenic multipotential cells withdisregulated self-renewal properties in which upon division, one daughter cell retainsstemness and the other becomes committed to a lineage. In the mammary gland, signalingpathways such as Hedgehog (Hh), Wnt/β-catenin, and Notch play a critical role inembryogenesis and organogenesis and maintenance of tissues in the adult throughregulation of the balance between self-renewal and differentiation of stem cells. Relevantliterature was identified by a PubMed search of English-language literature using the termsBreast cancer, stem cell, stemness pathways , therapeutic and such related terms. TargetingBreast cancer stem cells (BCSCs) may be achieved by a number of approaches such aschemotherapy sensitization, differentiating therapy, targeting stem cell elimination, targetingsignaling pathways and drug transporters, and inhibition of regulatory pathways involved inself-renewal. Targeting cells which have the potential to metastasize could be an importantaspect of the field as these are the cells that cause the majority of morbidity and mortality frombreast cancer.

Keywords:

Breast cancer , Stem cells , Pathways , self renewal , Therapeutic