CD99 and neoplasm: Many signals favoring tumor cells were significantly activated in C2, such as integrin-related signals (COL9A3 − (ITGA2+ITGB1), JAM3 − (ITGAM+ITGB2), COL6A1 − (ITGA1+ITGB1)), immune suppression signals (CD99 − PILRA), etc. (Figure S8E; Table S3).