EPHA4 and squamous cell lung carcinoma: Based on the RNA sequencing results from TCGA (The Cancer Genome Atlas) database (http://cancergenome.nih.gov), we determined that colorectal cancer tissues (n = 269) express significantly higher mRNA levels of EphrinB2, EphB1, EphB2, EphB3, and EphB4 than all other cancers surveyed (n = 3345; stomach n = 413; breast n = 901; lung adenocarcinoma n = 465; lung squamous cell carcinoma n = 407; hepatocellular carcinoma n = 132; ovarian n = 253; melanoma n = 82; uterine n = 365 and prostate n = 327), but lower levels of EphA4 (Fig. 1A).