• Code for proteins involved in control of cell division
• In particular, stimulating cell division (when growth factors attach to receptors on cell membrane, so cell division is required)
• Role in development of tumours
• Mutation could turn it into permanently activated oncogene
• Decreased methylation / increased acetylation causes excess transcription
• Cell division permanently activated; rapid / uncontrolled cell division
• Note – only need 1 mutated allele