The Role of Breast Cancer Stem Cells in Clinical Outcomes

Breast cancer stem cells (BCSCs) or tumor-initiating cells (TICs) constitute a small, dynamic subpopulation of breast tumors that plays a vital role in repopulating a heterogeneous tumor or simply seeding a new tumor following therapy. The BCSCs possess the intrinsic ability to survive therapy through a variety of mechanisms while the bulk tumor cells are eliminated. The surviving BCSCs, tumor cells and stroma constitute the minimal residual disease. Subsequently, BCSCs grow aggressively even in the presence of drugs and become highly invasive and metastatic in nature. They can also survive radiotherapy due to inherently high DNA repair capacity (radioresistance). The net result is frequent tumor relapse which is high in triple-negative breast cancer (TNBC) and is associated with poor patient outcomes. This redirects our focus to selectively target BCSCs or co-target BCSCs and bulk tumor cells to attain clinical success in metastatic breast cancer (MBC) patients.

In order to identify selective novel targets that are more vulnerable for BCSCs than normal mammary stem cells (MaSCs), the biological characteristics, molecular pathways, resistance mechanisms, plasticity of the BCSCs, and mathematical modeling of the behavior of the BCSCs along with their niche have to be investigated. Additionally, novel technology and targeted delivery of drugs through nanomedicine must be developed to improve the efficacy of treatment while also aiming to minimize the global toxicity to the patients.

Through this Research Topic, we welcome articles of different types – mini-reviews, full reviews, data articles, and clinical or pre-clinical articles – pertaining to the biological characteristics, molecular pathways, redox signaling, novel targets, resistance mechanisms, plasticity of the BCSCs, and mathematical modeling of the behavior of the BCSCs, along with nanoformulation and delivery of drugs to BCSCs.