Despite the robust expression profile of most TLRs in SCAP, we focused on the differential function of TLR2/TLR4 versus TLR3 activation, since these receptor systems are the most likely activated upon microbial infections in the dental pulp that are predominant with Gram-positive and -negative bacteria [30], possibly viruses [31] and endogenous mRNA released upon cell death. Here, TLR4 is linked to syringocystadenoma papilliferum.