SUV39H1 and esophageal squamous cell carcinoma: In the nucleus of the ESCC cell, CCAT1 functions as a suppressor of sprout RTK signaling antagonist 4 (SPRY4) by linking the enhancer of zeste homolog 2 (EZH2) and the suppressor of variegation 3-9 homolog 1 (SUV39H).