Heterogeneous populations may contain subpopulations with different phenotypic and genetic profiles. Among these are cancer stem cell-like cells (CSCs), a dynamically changing subpopulation of cancer-initiating cells (CICs) that arises due to the acquisition of malignant cellular transformations as part of a biological evolutionary process. Although, in theory, many tumors contain limited minority of CSCs, in practice, it is difficult to identify the cells that acquire the genetic/epigenetic alterations that lead to tumor initiation. As the name suggests, the CSC hypothesis describes a process driven by rare cellular components that display stem cell properties of self-renewal and differentiation: self-renewal promotes tumorigenesis, whereas differentiation contributes to the phenotypic heterogeneity of tumors.
The role of CSCs as adverse factors in ovarian cancer may reflect their suggested origin from aberrant CICs. Consistent with this, a subpopulation of cells isolated from mouse ovarian cancer cell lines and ascites of human ovarian cancer patients phenotypically resemble stem cells. CSCs are thought to be self-renewing and possess multipotency. This latter property enables CSCs to differentiate into diverse cells that display histologic heterogeneity and tumorigenicity, even in a subpopulation or a small minority of cells.
