In the May 10th issue of Nature Cell Biology, L. Vermeulen et al. from the University of Amsterdam (Netherlands) reported their study results correlating the level of Wnt signaling in tumors and colon cancer stem cells. With a Wnt reporter construct, the investigators observed that high activity of Wnt signaling was observed in tumor cells located close to stromal myofibroblasts. The data suggested that "Wnt activity and cancer stemness may be regulated by extrinsic cues. The researchers found that myofibroblast-secreted factors (e.g. hepatocyte growth factor) activated β-catenin transcription and cancer stem cell (CSC) clonogenicity. Interestingly, the study results also revealed that myofibroblast-secreted factors could also induce CSCs (activation of a quiescent population of CSCs?) in adenocarcinomas populated with differentiated tumor cells both in vitro and in vivo. The authors concluded from their observtions that "stemness of colon cancer cells is in part orchestrated by the microenvironment and is a much more dynamic quality than previously expected that can be defined by high Wnt activity."

In the May 7th issue of Cell Stem Cell, J. D. Lathia et al. from the Cleveland Clinic published their study results on identifying other markers that may have a role in the maintenance of cancer stem cells (CSCs). The investigators analyzed glioblastoma stem cells (GSCs) from primary tissue specimens of cancer patients. The CSC were enriched using CD133 (Prominin-1) marker. The study data revealed that cells from the perivascular regions of the primary tumor samples co-expressed integrin α6 in the GSC-enriched subpopulation of cells. Additionally, targeting integrin α6 inhibited GSC self-renewal, proliferation, and its tumor-initiating potential. The authors concluded that their study results "provide evidence that GSCs express high levels of integrin α6, which can serve not only as an enrichment marker but also as a promising antiglioblastoma therapy."