Induced pluripotent stem cells are induced pluripotent stem cell-like cells

Gold is rare and precious, while pyrite (FeS2) is abundant and cheap. Pyrite is nicknamed fool9 s gold, since pyrite looks like gold and it is even shinier and brighter than gold. It is very difficult to recognize the differences between a real natural gold and a gold-like rock (pyrite) to non-professional persons [1] , but we know that all that glitters is not gold. Similar mistakes can happen in biomedical research as well. Pluripotent embryonic or adult stem cells can self-renew and proliferate into different cells, and these stem cells are very valuable in transplantation and gene therapy. Because the government of the United States of America and other governments have tight regulations restricting embryonic stem cell work, this has driven research towards finding stem cells from adult sources rather than embryos. Instead of acquiring useful adult stem cells from adult tissues, in recent years some researchers have claimed that they could magically turn adult somatic cells into induced pluripotent stem cells [2,3] . Is this real? Or is this too good to be true? Dr. Liu has actively challenged the validity of the so-called induced pluripotent stem cells since 2008; he suspected that pre-existing adult stem cells might have played a vital and essential role in the process of producing those induced pluripotent stem cells [4] . It was later proven that only real adult stem cells (muse cells) can generate those claimed induced pluripotent stem cells [5,6] . Several research groups have found that those proclaimed induced stem cells had more abnormal chromosomes [7] , more protein-coding point mutations [8] , more abnormal epigenomic reprogramming and DNA methylation [9-11] , and more copy number variations [12,13]