LGR5 and colorectal carcinoma: EGF significantly induced STAT3 phosphorylation and elevated the mRNA levels of LGR5 in the HT29 cells (Fig. 4d), implying that addition of EGF activated STAT3 in the cancer stem-like tumorspheres, thus contributing to the formation and survival of EGFR-positive CRC stem-like tumorspheres.