PREX2 and adenocarcinoma: Besides, PREX2 mutations were only occurred in males (7/72, 9.7%), which is significantly more frequent than in females (0%; P = 0.042); PREX2 mutations were only occurred in smokers (7/60, 12%), which was significantly higher in never smokers (0%; P = 0.013), and PREX2 mutations were significantly higher in patients with squamous (4/15, 26.7%) than those with adenocarcinoma (2/96, 2.1%; P = 0.0029).