NSUN2 Expression in Nasopharyngeal Carcinoma

The TMA with 125 NPC patients were purchased from Superbiotek (Shanghai, China). IHC determined the expression of NSUN2 in NPC and normal tissues as previously described (16 (link)). After deparaffinizing and blocking endogenous peroxidase, the slides were incubated with antibody against NSUN2 (1:800 dilution, 20854-1-AP, Proteintech, Wuhan, China). Arrays were then washed with PBS and incubated for 30 min with the EnVision™+ Dual Link System-HRP (Dako, Carpinteria, CA). After rinsing thrice with PBS for 3 min each time, the slides were incubated with DAB reagent (Dako, Carpinteria, CA) for 3–5 min and evaluated under a light microscope. The TMA were then counter-stained with hematoxylin and observed under a Leica microscope (DM4000b, Wetzlar, Germany). The results were evaluated independently by two blinded pathologists according to the following scoring criteria: 0, negative; 1, weak; and 2–3, strong. The degree of staining was scored as the proportion of the positive staining area relative to the whole cancerous area: 0, <5%; 1, 5–25%; 2, 26–50%; 3, 51–75%; and 4, >75%.