Xinyu Yang1, Jiale Chen1, Ning Wang1, Zhui Liu1, Yuan Li2. 1. Department of Pediatric Surgery, West China Hospital, Sichuan University, Chengdu, China. 2. Institute of Digestive Surgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China. Electronic address: liyuanletters@163.com.