The Colon Cancer Stem Cell Microenvironment Holds Keys to Future Cancer Therapy

Background: Colorectal cancer remains the most common gastrointestinal cancer. While screening combined with effective surgical treatment has reduced its mortality, we still do not have effective means to prevent recurrence nor to treat metastatic disease. What we know about cancer biology has gone through revolutionary changes in recent decades. The advent of the cancer stem cell theory has accelerated our understanding of the cancer cell. However, there is increasing evidence that cancer cells are influenced by their surrounding microenvironment. Purpose: This review divides the tumor microenvironment into four functional components-the stem cell niche, cancer stroma, immune cells, and vascular endothelia-and examines their individual and collective influence on the growth and metastasis of the colon cancer stem cell. The discussion will highlight the need to fully exploit the tumor microenvironment when designing future prognostic tools and therapies.