Figure 9.

Graphical model of the generation of tumor-initiating cells (TICs) and the OCT4 molecular targets regulated in OCT4-transduced breast cells (OTBCs). (a) Illustration of the proposed model for the generation of OTBCs endowed with tumor-initiating ability. (b) Endogenous expression of OCT4 in normal breast tissue results in aberrant self-renewal and expansion of an undifferentiated early stem/progenitor population. OCT4 expression results in an activation of self-renewal transcription factors (TFs) and a concomitant repression of tumor suppressor genes that allow cells to immortalize and gain stem cell-like features. CDH1, E-cadherin; EMT, epithelial-to-mesenchymal transition; hTERT, human telomerase reverse transcriptase; miRNA, microRNA; TSG, tumor suppressor gene.