SPRY4 and esophageal squamous cell carcinoma: Furthermore, several studies demonstrated that SPRY4-IT1, CCAT2 and prostate cancer-associated ncRNA transcript 1 (PCAT-1) were upregulated in ESCC tissues compared to the adjacent noncancerous tissues, and high expression of these lncRNAs was significantly associated with the clinical pathological stage and poor survival rate of ESCC [75,76,77].