"c" for Cancer Stem Cell

腫瘤幹細胞

Yesterday, during an interview with the press, one of the topic that I took quite a long time to clarify is regarding to cancer stem cells.

To lots of people, when they heard of stem cell and cancer, immediately they are thinking of the normal or good (I would put it) stem cell such as those from bone marrow that are used to alleviate some of the adverse effect faced by the cancer patients undergoing chemoradiotherapy.

They hardly can imagine, there is a group of stem cells that are evil or cancerous that are found in the cancer cell population itself.

So, what is cancer stem cell then?

The cancer stem cells, is a small subset of cancer cells, which constitute a reservoir of self-sustaining cells with the exclusive ability to self-renew and maintain the tumor. These cancer stem cells have the capacity to both divide and expand the cancer stem cell pool and to differentiate into the heterogeneous nontumorigenic cancer cell types that in most cases appear to constitute the bulk of the cancer cells within the tumor.
Source: http://cancerres.aacrjournals.org/cgi/content/full/66/19/9339

In order words, they are......

are cancer cells (found within tumors or hematological cancers) that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. These cells are therefore tumorigenic (tumor-forming), perhaps in contrast to other non-tumorigenic cancer cells.
Source: Wikepedia

These cancer stem cells, currently, is believed as one of cause of cancer recurrent after anti-cancer therapy been stop when a cancer patient been certified as cured from cancer. This is mainly because these cancer stem cells still remain in the cancer patient as these cells are resistance to most conventional chemotherapies widely used to date.

That is why, on Sep 11th 2008, there is one striking heading published in The Economist

Cancer stem cells: The root of all evil?

Viewing these phenomena, till late, very little is known about all these cancer stem cells and researches are on-going to understand them further and to discover novel therapy that specifically targeting these cells.

At this point, I am wondering, under tumor microenvironment, these cancer stem cells are existed. If we managed to revert these tumor microenvironment to normal microenviroenment where normal cells are living, can these cancer stem cells revert to normal stem cells? As currently, there is hypothesis indicating that cancer stem cells could be derived from normal stem cells that undergo cancerous mutation.