POU5F1 and esophageal squamous cell carcinoma: KLF3-AS1 is downregulated in esophageal squamous cell carcinoma stem cells, promoting cell migration and invasion by being unable to sponge miR-185-5p, which induces KLF3 mRNA degradation, thereby preventing transcriptional repression of SOX2 and OCT4 by KLF3 [68], and acts as a competing endogenous tumor suppressor RNA in gastric cancer [69] and osteosarcoma [70].