The mandatory fresh frozen tumor biopsy sample can be obtained through standard-of-care surgical procedures (i.e., performed at progression, for cytoreduction, to proof progressive disease, or to reduce mass effect on the surrounding brain tissue). Thus, surgical procedures are standard-of-care and not part of trial participation. Fresh frozen tumor tissue must have been obtained ≤2 months before inclusion, and without any type of anti-cancer therapy within those ≤2 months. After surgical procedures, patients must meet the following inclusion criteria: