High SRSF1 levels (IRS ≥ 6) were found in 15/21 cases (71%) of oligodendrogliomas (Figure 2), whereas only 6/21 (29%) showed low expression (IRS < 6); all cases (6/6) of grade III anaplastic oligodendrogliomas had an IRS value ≥ 6. Here, SRSF1 is linked to anaplastic oligodendroglioma.