Fig. 2

Alpha diversity and Beta diversity of HPSCC and CG compared. Alpha diversity is based on A Ace index shown in violin plot, illustrating lower richness of microbiota (p = 0.0083); B Shannon index shown in violin plot, illustrating the lower evenness of microbiota in HPSCC group, compared to CG (p < 0.0001); C Observed species index shown in violin plot, illustrating the lower evenness of microbiota in HPSCC group, compared to CG (p = 0.0049). Beta diversity was used to evaluate the similarity between groups and its measurements were as follows: D PCoA with weighted UniFrac in HPSCC presented statistical difference compared to CG. (Adonis analysis: R2 = 0.1136; p = 0.001) E NMDS in HPSCC presented a statistical difference compared to CG. (Anosim analysis: R2 = 0.0945; p = 0.006)