PIK3CA and esophageal squamous cell carcinoma: In addition, other genes that recurrently mutated in ESCC include FAT1 (10%), PTCH1 (10%), EP300 (5%), FAT2 (5%), FBXW7 (5%), KMT2D (5%), NFE2L2 (5%), NOTCH1 (5%), PIK3CA (5%), RB1 (5%), RIPK4 (5%) and TP63 (5%).