CD274 and Epstein-Barr virus infection: EBV infection; CpG island methylation; CCDKN2A silencing; JAK2, CD274, PDCD1LG2,ERBB2, PD‐L1 and PD‐L2 amplification; mutations in PIK3CA (80%), ARID1A (55%) and BCOR (23%) [A].