Stem Cells: In Sickness and in Health.

Stem cells are undifferentiated cells with the ability to proliferate and convert to different types of differentiated cells that make up the various tissues and organs in the body. They exist both in embryos as pluripotent stem cells that can differentiate into the three germ layers and as multipotent or unipotent stem cells in adult tissues to aid in repair and homeostasis. Perturbations in these cells' normal functions can give rise to a wide variety of diseases. In this review, we discuss the origin of different stem cell types, their properties and characteristics, their role in tissue homeostasis, current research, and their potential applications in various life-threatening diseases. We focus on neural stem cells, their role in neurogenesis and how they can be exploited to treat diseases of the brain including neurodegenerative diseases and cancer. Next, we explore current research in Induced Pluripotent Stem Cells (iPSC) techniques and their clinical applications in regenerative and personalized medicine. Lastly, we tackle a special type of stem cells called Cancer Stem Cells (CSCs) and how they can be responsible for therapy resistance and tumor recurrence and explore ways to target them.