The calcium and zink dependent protein S100A9 regulates the accumulation of tumor infiltrating MDSCs [48], and tasquinimod as a representative of quinoline compounds which recently were described as a strong binders to S100A9 [44], may have inhibited the MDSC accumulation and thereby prohibited MDSCs/M2 macrophages to act in a pro-angiogenic and pro-tumor fashion. Here, S100A9 is linked to neoplasm.