Single cell and microarray data collection
Single-cell data were obtained from GSE150430. Data from 15 NPC tumor
and 1 normal biopsies were used for global analysis. Epithelial cells
were identified using EPCAM, KRT5, KRT15 and KRT19. ENOX2 expression in
malignant tumor cells were obtained from 11 patients. ENOX2 expression
was indicated by color scale. Data visualizations were generated by
plotly. NPC gene expression profiling datasets GSE34573, GSE53819 and
GSE12452, and gene methylation profiling datasets GSE52068 were obtained
from the gene expression omnibus (GEO,
https://www.ncbi.nlm.nih.gov/geo/) database of The National Center
for Biotechnology Information. GSE12452 contained 31 NPC specimens and
10 normal nasopharyngeal tissues, GSE53819 included 18 NPC and 18 normal
specimens whereas GSE34573 included 13 NPC specimens and 3 normal
nasopharyngeal tissues excised by laser microdissection. The datasets
were based on the GPL570 [HG-U133_Plus_2] Affymetrix Human Genome
U133 Plus 2.0 Array platform. GSE52068 used Infinium Human Methylation
450K BeadChip and the probes targeted CpG sites of genes. CpG sites are
usually found at or near transcription start site (TSS), so high level
of methylation of CpG might lead to suppressed expression of RNA
transcripts.
Statistics
Differences in quantitative variables were analyzed by the Mann–Whitney
U test when comparing 2 groups and by the two-way ANOVA or
Kruskal-Wallis with Dunn’s post-test when comparing >2
groups when appropriate. A p value < 0.05 was considered as
statistically significant.