CREB1 and neoplasm: However, CREB1 AA genotype was more common in patients with tumors located in limbs than in head or trunk (31.7% versus 15.9%, p = 0.009) and tumors with Clark levels III to V than in those with tumors of I or II Clark levels (27.8% versus 13.7%, p = 0.012), and MITF AA genotype was more common in patients with III or IV tumor stage than in those with tumors at 0 to II stages (46.1% versus 24.9%, p = 0.007).