PTGER4 and laryngotracheoesophageal cleft: The positive expression rates of SHOX2, RASSF1A, and PTGER4 in cancer tissues of LC patients were 44.0%, 54.00%, and 50.00%, respectively, which were significantly lower than those in paracancerous tissues, which were 90.00%, 96.00%, and 82.00%, respectively (P < 0.05).