Fig. 1

Representative correlation plots for mRNA expression. a Non-smoker vs. smoker groups. b Non-periodontitis vs. periodontitis groups. The r _s values in the scatter plot are shown as the median and interquartile of Spearman’s rank correlation coefficients between the cases of the groups. P values near the line with arrows at both ends are P values determined by the Student Wilcoxon rank sum test to compare the Spearman rank correlation coefficients between two groups shown in the x and y axes