HRAS is part of the Ras oncogene family， whose members are related to the transforming genes of mammalian sarcoma retroviruses. The products encoded by these genes participate in signal transduction pathways. These proteins can bind GTP and GDP， and they have intrinsic GTPase activity. HRAS go trough a continuous cycle of de- and re-palmitoylation， which mediates its rapid exchange between the plasma membrane and the Golgi apparatus. Mutations in HRAS result in Costello syndrome， a disease characterized by increased growth at the prenatal stage， growth deficiency at the postnatal stage， predisposition to tumor formation， mental retardation， skin and musculoskeletal abnormalities， distinctive facial appearance and cardiovascular abnormalities. Defects in this HRAS gene are implicated in a range of cancers， including bladder cancer， follicular thyroid cancer， and oral squamous cell carcinoma.
