NRAS and nasopharyngeal carcinoma: Besides NF-κB pathway, we also identified missense mutation of NRAS in Xeno23, 32 and C666-1 as well as a homozygous missense mutation of PTEN in Xeno47 (Fig. 8a; Supplementary Fig. 19), which further suggests an aberrantly activated phosphoinositide-3-kinase (PI3K)/AKT signaling pathway in EBV+ve NPC PDXs and cell lines.