Upregulation of the mesenchymal-to-epithelial transition (MET) marker GRHL2 in the nine colorectal CTC lines and in colorectal cancer samples. (A) Comparison of the expression of the indicated MET transcription factors in CTC lines and SW620 cells (microarray data). (B) The GRHL2 MET marker is significantly upregulated in CTC lines compared with SW620 cells. (C) GRHL2 mRNA level in paired normal colorectal epithelium and primary colorectal cancer samples (n = 27). Data are from a cohort of patients with colon neoplasms (GSE41258). (D) GRHL2 mRNA level (same cohort as in (C)) in normal colorectal epithelium (n = 41), primary (n = 41), and lung and liver metastatic (n = 66) colorectal cancer samples. (E) GRHL2 relative gene expression by RT-qPCR in SW620 cells and in each CTC line. (F) Immunofluorescence analysis of GRHL2 protein expression in the nine CTC cell lines. e: p-value = 2.71 × 10−9; f: p-value = 1.80 × 10−17; g: p-value = 1.54 × 10−12. All the RT-qPCR results were normalized to the B2M expression level in each sample; * p < 0.05, ** p < 0.01, *** p < 0.001, ns: not significan.