Surely the ability to make an iPSC means that "a cell" can have "stemness"? - Mr. Gunn

@Mr. Gunn - It seem like, but it's fuzzy - Alexey

Dr. Lander didn't say something new and unexpected. I agree with him about "cancer stem cell", but you can't extrapolate to normal tissue SC. It's know that they live by populations or community withing the niche and if they loose the niche they loose the stemness. That's why we have trouble to characterize them on single cell level. But it's not disprove SC existence. - Alexey

Yes, that's exactly what I was trying to say, Alexey. Just because it's hard to characterize, doesn't mean it's not real. - Mr. Gunn

Saw no comments, in the article, about successful purification of stem cells, e.g. http://www.ncbi.nlm.nih.gov/pubmed... and http://www.ncbi.nlm.nih.gov/pubmed... - Jim Till

My question , "What about purified stem cells?", has now been answered by Arthur Lander. His response includes the comment that "feedback regulation just like that in my Figure 1 must occur in the HSC system". I agree with this comment. See: http://jbiol.com/content... #openaccess - Jim Till

I agree that HSC is population, we study it on population level, but disagree with an assumption that we are blindly studying something that doesn't exist at all (there are no stem cells). So it's not "holding back biology", it's new biology. - Alexey

we knew that pure single HSC doesn't represent the population, we knew that HSC population is very heterogeneous, so what's new? - Alexey

link to the article - http://jbiol.com/content... - Alexey

Is the debate about 'stemness' becoming another version of the nature-nurture debate? For a recent commentary on the latter debate, see "'Freaks' help scientist unravel nature and nurture", http://www.bio-medicine.org/biology... So, which 'stem cells' are the 'freaks'? - Jim Till

Q&A: Is stem cell research misguided? http://www.the-scientist.com/blog... - Jim Till

Related discussion at http://ff.im/8Xiql - Jim Till

I've cited this discussion in a blog post: A contrarian view of 'stemness' http://cancerstemcellnews.blogspot.com/2009... #cancerSC - Jim Till

one more my input in the story - http://hematopoiesis.info/2009... - Alexey