Identify all the factors which make a cell more radiosensitive.

• A. Long dividing future
• B. Unspecialized cell
• C. Rapidly reproducing cells
• D. All of the above

Answer: (D)

Radiosensitivity depends on how actively a cell can divide and how specialized it is. Cells that can divide many times in the future, are not highly differentiated, and are currently dividing rapidly are more vulnerable to radiation because DNA damage interferes with ongoing replication and progression through the cell cycle. This idea is captured by the principle that radiosensitivity increases with reproductive capability and decreases with differentiation. Therefore a cell that has a long dividing future, is unspecialized, and is rapidly reproducing is more radiosensitive. In contrast, mature, differentiated, and slowly dividing cells tend to be more resistant to radiation.