Oneliner_2415

OneLiner

Retinoblastoma is inherited in 40% of cases. A point mutation inactivates the RB tumor-suppressor gene on chromosome 13, which encodes a protein that binds to and regulates the E2F transcription factors. When both alleles are lost, the E2F transcription factors are uninhibited and cause the cell to move from a quiescent stage into the synthesis phase. As a result of the mutation she carries in her functioning RB tumor-suppressor gene, the patient is at increased risk of developing osteosarcomas later in life.