Stem Cell Origin of Cancer: Biological Principles and Clinical Strategies for Chemoprevention and Maintenance Therapy in Cancer Care

In this Perspective, we discuss a stem cell origin of cancer and consider the biological principles and clinical strategies for chemoprevention in cancer care. We examine the role of vitamin D, tumor microenvironment, and GLP-1R agonists in chemoprevention and maintenance therapy. If cancer were a stem cell disease, then keeping stem cells pristine and healthy would be essential and keeping cancer stem cells (CSC) dormant and innocuous necessary. According to a stem cell (unified) theory of cancer, chemoprevention is effective when we refrain from disturbing CSCs and/or inciting non-CSCs with inflammatory factors and/or insulinemic habits. We postulate that many effective chemoprevention (and anti-cancer) treatments modulate stem-ness/stem-like cells and operate through anti-stem-ness/stem-like mechanisms. They affect progenitor stem cells versus progeny differentiated cells as well as their malignant counterparts and respective microenvironments. We propose that to fulfill the visions and missions of cancer prevention, it is imperative to first formulate a pertinent scientific theory and then adopt and adhere to the proper scientific method in our conduct of cancer research and provision of cancer care.