PDCD1 and cancer: Previous research has revealed that the downregulation of EMX2OS in classical papillary thyroid cancer might independently predict shorter recurrence-free survival [35], while the overexpression of EMX2OS in ovarian cancer and EMX2OS/miR-654/AKT3 axis may target PD-L1 (programmed cell death protein 1) to suppress the initiation and progression of cancer [36].