Among the bacteria resulting significantly associated with the tumor (more than two folds increased abundance with respect to HC) in our study, Fusobacterium nucleatum, Bacteroides fragilis and Gemella haemolysans were found to be significantly associated with CCL2 blood levels (p = 0.030, 0.050 and 0.001, respectively) (Figure 6A–C), while Streptococcus intermedius was not associated. This evidence concerns the gene CCL2 and neoplasm.