There are reports indicated that overexpression of epigenetics modifiers, Enhancer of Zeste homolog 2, protein methyltransferase, (EZH2) [33] and DNA methyltransferase 1 (DNMT1) [34] in NPC correlated with NPC tumorigenesis; thus, we chose EZH2 inhibitor “GSK126” and DNA methylation inhibitor “decitabine” (a nucleotide analogue of DNMT1) in our NPC-PDX drug screening model. Here, DNMT1 is linked to nasopharyngeal carcinoma.