The analysis of CK7, ELF3, EGFR, and EphB4 mRNAs in PBMCs for the detection of CTCs have been reported in various epithelial cancers including NSCLC [11,12,13,14], respectively; however, a combined of these four markers in NSCLC has not yet been reported. The gene discussed is EPHB4; the disease is non-small cell lung carcinoma.