With all the breaking news stories that come out on cutting-edge stem cell findings each week, it can be easy to lose sight of the bigger picture. Yes, the stem cell family, which includes all of the varieties of stem cells we've discovered so far, is very large, and growing larger with new children, and cousins, and uncles and aunts being discovered or created all the time, but a key feature they all share is their potential to improve our lives.

Our understanding of these cells and their incredible potential to treat diseases, fight cancers, heal wounds, and, in essence, save lives, has grown hugely since we first unknowingly used them in World War II. However, the more we learn about stem cells the more we realize we have yet to understand. The column this article originally appeared in, Biology Bytes, has strived to explore the different stem cell types in detail, including their history, their biology, their potential, their applications in the clinic, and the numerous remaining questions. However, the ways in which the different types of stem cells came to be accepted into the stem cell family is itself an interesting story, and one that can help paint a useful bigger picture.

Hematopoietic Stem Cells: The first time stem cells were successfully used to treat patients was during World War II. However, at the time, people did not know they were using stem cells. During World War II, people exposed to lethal doses of radiation were given bone marrow transplants that, somehow, could cure them. Much later it was discovered that the responsible agents in the bone marrow were hematopoietic stem cells (HSCs).