Accordingly, an increased level of Sphingomonas in healthy compared to tumoral mammary tissue has been observed to be associated with a higher expression of TLR2, -5, and -9 and of antimicrobial response effectors IL-12A, bactericidal/permeability-increasing protein (BPI), and myeloperoxidase (MPO), suggesting its possible protective role in cancer by sustaining immunosurveillance [58]. Here, MPO is linked to cancer.