Demystifying the Differences Between Tumor-Initiating Cells and Cancer Stem Cells in Colon Cancer

Purpose of Review

Tumor-initiating cells and cancer stem cells refer to a subpopulation of self-renewing cells involved in tumor initiation and tumor maintenance, respectively. With this review, we aimed to define the functional and molecular differences between both cell types in the context of colon cancer.

Recent Findings

Recent evidence suggests that the two major stem cell populations in the normal intestinal crypt have tumor-initiating capacity and could be the cell-of-origin in colon cancer. Activation of the Wnt/β-catenin pathway (an early event in mouse intestinal carcinogenesis) in the crypt base columnar stem cells and reserve stem cells leads to adenoma formation, supporting a role in tumor initiation. On the other hand, colon cancer stem cells express several membrane markers facilitating their isolation by FACS and are associated with treatment resistance and higher metastatic potential.

Summary

Tumor-initiating cells and cancer stem cells express distinct markers, display discrete biological functions, and can be studied using different molecular and cellular approaches. While cancer stem cells may be derived from tumor-initiating cells, these terms are not necessarily interchangeable and more likely reflect a specific cell state.