MUC1 and idiopathic pulmonary fibrosis: In the aforementioned large-scale survey conducted by the Japanese Association for Chest Surgery, seven of the aforementioned conventional risk factors were identified as significant independent risk factors for AE [48]: prior history of AE (assigned score 5), UIP pattern (4), anatomical segmentectomy or more extensive surgical procedure (4), male gender (3), preoperative steroid use (3), preoperative serum KL-6 > 1000 U/mL (2) and preoperative %VC < 80 (1).