Therefore, we analysed the glycosylation profile of internalized cystatin F. As a model, we used U-251 MG glioblastoma cells that do not express cystatin F. However, these cells stained positive for cystatin F after culturing in conditioned media from NK-92 (Fig. 7B) or U-937 cells (Fig. 7D). This evidence concerns the gene CST7 and glioblastoma.