CDKN2A and glioblastoma: Of note, 7 genes that appeared in this OSC list were also present in the top-30 ranking obtained for the GBM data set, including the known cancer genes CDKN2A and NF1 as well as RFC4, a gene encoding a protein associated with BRCA1 that may sensor abnormal DNA structures and/or regulate post-replication repair processes [14].