CCL2 and neoplasm: Recently Yang et al. showed in their experiments, that in ACC the mechanism of CCL2/CCR2 axis in the interactions between tumor cells and tumor-associated macrophages during the progression of salivary ACC, promotes a polarization to M2 tumor-associated macrophages [20], which explains the significantly higher polarization (p = 0.0005) of macrophages in the M2-subpopulation found in our study.