NF1 and neoplasm: NF1 encodes neurofibromin 1, a cytoplasmic protein highly expressed in neurons, Schwann cells, oligodendrocytes, and leukocytes but also involved in RAS pathway as a tumor suppressor through its inhibiting activity as GAP (GTPase-activating protein) that converts the active RAS-GTP to RAS-GDP (Trovó-Marqui and Tajara, 2006).