CAMKK2 and central nervous system cancer: Recent studies have shown that miR-224 is more highly expressed in not only HCC but also esophageal cancer, non-small cell lung cancer, colorectal cancer, cervical cancer and glioma, and this molecule has a proliferative effect on these cancer cells through direct interactions with various tumor-suppressor genes, such as CAMKK2, ADAM17, Homeobox D 10 and RKIP [63–68].