Cancer researchers are discovering that at least some tumors arise from cancer stem cells that share characteristics with other kinds of stem cells.
What are stem cells? They are cells inside us that can divide and renew themselves throughout life. Stem cells have an unrivaled capacity to drive and shape growth by proliferating through repeated cycles of cell division.
Embryonic stem cells arise within days of conception inside a microscopic, still-round embryo, and they can give rise to any kind of cell within the organism -- a potential researchers call "pluripotency." In adults, stem cells are rare and different from most other cells.
Most other cells in adults have reached a terminal stage of development. They are specialized -- "differentiated" -- meaning they perform just one defined set of tasks. They rarely, if ever, divide to generate new cells. They may wear out and eventually die.
Stem cells do not normally wear out and are essentially immortal. They never commit to a final development into a specialized cell.
When tumor cells from patients are separated from one another and given a chance to grow in a laboratory culture dish, only a very small percentage of the tumor cells are capable of regenerating the tumor. Some researchers believe these are the cancer stem cells.
Read more at Jeffrey Norris, UCSF Science Cafe