S100A9 and neoplasm: We found that AQP9 in glioblastoma tissue biopsies is expressed in a subset of malignant astrocytic cells and in tumor infiltrating CD15+ and Calgranulin B+ cells, thus identifying these cells as myelomonocytic linage cells, including neutrophils, eosinophils, and some monocytes, but not basophils [13].