Moreover, RASSF1A hypermethylation significantly associated to secondary glioblastoma phenotype, as 4 of 5, secondary glioblastomas, suffered hypermethylation on its promoter, while only 4 of 19 primary glioblastomas did so (P = 0.028, Fisher's exact test). The gene discussed is RASSF1; the disease is glioblastoma.