1. Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, P.R. China
2. Department of Hepatobiliary Surgery, China‑Japan Friendship Hospital, Beijing 100029, P.R. China
3. Research and Early Development, Bristol Myers Squibb, Princeton, NJ 08540, USA
4. Department of Pathology, China‑Japan Friendship Hospital, Beijing 100029, P.R. China