KLF4 and esophageal squamous cell carcinoma: The migration and invasion of esophageal squamous cell carcinoma (ESCC) is positively correlated with CDR1as, CDR1as acts as an miR-7 sponge to promote tumor progression by increasing the function of the stem cell marker Klf-4 and homeobox gene B13 (HOXB13)-mediated nuclear factor (NF-κB) [63, 64].