We have known since 1994 that the recurrence of some types of cancer can be driven by cancer- specific stem cells (cancerous duplicates of the normal stem cells that we all carry in our bone marrow and our blood stream). Whether this is true of all cancers is definitively not known.
Specific prostate cancer stem cells certainly exist see for example the article by Wang et al. from 2009 and the review by Shen and Abate-Shen just this year – but whether these (or other) prostate cancer stem cells really hold out the potential suggested by Maitland and Collins, we still don’t know.
There has been an explosion of basic research in this field in recent years, but we still have to learn whether it is possible to develop types of drug therapy that can specifically and selectively target prostate cancer stem cells and that’s long before we will know whether such drugs can actually be used effectively and safely to treat patients.