Other genes with high level amplifications include PRKAB2 (6–10 copies in ovarian cancer), MDM4 (10–30 copies in glioblastoma), MDM2 (10–15 copies in lung adenocarcinoma), PIK3CA (5–20 copies in lung squamous cancer), DCUN1D1 (5–15 copies in lung squamous cancer), FADD and PPFIA1 (each with 5–10 copies in head and neck cancer), NDUFC2 (5–15 copies in ovarian cancer), and RAP1B (5–15 copies in lung adenocarcinoma). Here, MDM4 is linked to head and neck cancer.