Fig. 2

The microbial profile differs between NPC and normal nasopharyngeal tissues. A Contamination removal procedure for 16S rRNA gene sequencing. B Overview of the bacterial differences in 343 NPC tumours and 36 normal nasopharyngeal tissues at the phylum level using the Circos plot. C Notched boxplots show the differential abundances of bacteria between NPC and normal nasopharyngeal tissues. The comparison was performed with the Wilcoxon rank-sum test. D Alpha diversity violin plot (Shannon and Simpson indexes) revealed differences in the community richness and evenness of the bacteria between NPC and normal nasopharyngeal tissues. The comparison was performed with the Wilcoxon rank-sum test. E Principal coordinate analysis (PCoA) using Bray-Curtis and unweighted UniFrac distances of beta diversity revealed the diversity distance of bacteria between NPC and normal nasopharyngeal tissues