The hierarchical model of cancer

The hierarchical model of cancer suggests that tumors are made up of a spectrum of cells, similar to normal tissues. At the top are cancer stem cells that can self-renew and produce different types of cancer cells. These cancer stem cells drive tumor growth and can regenerate the tumor even after treatment. Below them are more specialized, bulk tumor cells that make up most of the tumor mass but have limited ability to reproduce. This hierarchy helps us understand why some cancers are hard to eliminate completely and highlights the importance of targeting cancer stem cells for effective treatment.