Barbagallo et al. [18,19] investigated the expression of 12 different types of circRNAs in both human unaffected brain parenchyma and CNS glial tumors and found that circSMARCA5 is the best example of downregulated circRNAs in WHO grade IV GBM specimens compared to normal cerebral tissue; particularly, circSMARCA5 seems to act as a tumor-suppressor RNA, negatively regulating cell migration through the RNA binding to protein SRSF1, which, in normal conditions, acts as an oncoprotein with a positive regulatory role on cell migration [18,19]. The gene discussed is SRSF1; the disease is glioblastoma.