Dr. Louis' laboratory has studied the molecular genetic basis of human brain tumors, both common sporadic brain tumors as well as rarer, inherited brain tumor syndromes. Most of the work has focused on malignant gliomas. The laboratory was the first to demonstrate that molecular genetic analysis could be used to divide glioblastomas into clinicopathologically distinct genetic subsets. The laboratory has also shown that specific genetic alterations are powerful predictors of chemotherapeutic response and survival in patients with anaplastic oligodendrogliomas. Recent work focused on the effects of chemotherapy on malignant glioma genotype at the time of recurrence and, in collaboration, on glioma epigenetics.