Having only had their existence substantiated in 1997, Cancer Stem Cells (CSCs) were identified when researchers discovered that certain cancer cells harvested from a tumor had the ability to regrow a tumor when transplanted to a new location. These CSCs did so through the stem cell process of self-renewal, thus their given name. Researchers theorize that traditional forms of cancer treatment such as chemotherapy target only differentiated cells that form the bulk of the tumor however the cells that actually grow the tumor, CSCs, remain unscathed due in part to inherent defense mechanisms to radiation and chemotherapy. Even one such CSC left may fuel the growth of a new tumor following treatment. An alternative to traditional treatment could be just to target the CSCs as seen below: