Cancer stem cells (CSCs) also known as
cancer-initiating cells (CIC), are responsible for the sustained and uncontrolled growth of malignant
tumors and are proposed to play significant roles in
metastasis and recurrence. Several hypotheses have proposed that the events in either stem and/or differentiated cells, such as
genomic instability, inflammatory microenvironment, cell fusion, and lateral gene transfer, should be considered as the possible origin of CSCs. However, until now, the exact origin of CSC has been obscure. The development of induced pluripotent stem cells (iPSCs) in 2007, by Yamanaka's group, has been met with much fervency and hailed as a breakthrough discovery by the scientific and research communities, especially in regeneration
therapy. The studies on the development of CSC from iPSCs should also open a new page of
cancer research, which will help in designing new
therapies applicable to CSCs. Currently most reviews have focused on CSCs and CSC niches. However, the insight into the niche before the CSC niche should also be of keen interest. This review introduces the novel concept of
cancer initiation introducing the conversion of iPSCs to CSCs and proposes a relationship between the inflammatory microenvironment and
cancer initiation as the key concept of the
cancer-inducing niche responsible for the development of CSC.