ISG15 and glioblastoma: In contrast to normal tissues, ISG15 was found to be markedly expressed in breast cancer, uterine corpus endometrial carcinoma, glioblastoma multiforme, colon cancer, head and neck squamous carcinoma, clear cell renal cell carcinoma, pancreatic adenocarcinoma, ovarian cancer, and lung adenocarcinoma (Fig. 1B).