Lipid droplets: A New Player in Colorectal Cancer Stem Cells Unveiled by Spectroscopic Imaging.

The Cancer Stem Cell (CSC) model is describing tumors as a hierarchical organizedsystem and CSCs are suggested to be responsible for cancer recurrenceafter therapy. The identification of specific markers of CSCs is thereforeof paramount importance. Here we show that high levels of Lipid Droplets(LDs) are a distinctive mark of CSCs in colorectal (CR) cancer. This increasedlipid content was clearly revealed by label free Raman spectroscopyand it directly correlates with well‐accepted CR‐CSCs markers as CD133 andWnt pathway activity. By xenotransplantation experiments, we have finallydemonstrated that CR‐CSCs overexpressing LDs retain most tumorigenic potential.A relevant conceptual advance in this work is the demonstration that a cellularorganelle, the Lipid Droplet, is a signature of CSCs, in addition to molecularmarkers.A further functional characterization of LDs could lead soon to d