Which statement is true about mitotic activity and radiosensitivity according to Bergonie and Tribondeau?

• A. Radiosensitivity increases with greater mitotic activity
• B. Radiosensitivity decreases with greater mitotic activity
• C. Radiosensitivity is unrelated to mitotic activity
• D. Radiosensitivity depends on tissue size

Answer: (A)

Radiosensitivity follows how actively a cell divides and how undifferentiated it is. Bergonie and Tribondeau showed that tissues with high mitotic activity and little differentiation have the greatest sensitivity to radiation, because their cells have strong reproductive potential and less specialized DNA repair mechanisms. When radiation damages DNA, cells that are rapidly dividing have less time to repair and are more likely to die during or after division, especially as they enter mitosis. In contrast, well-differentiated, slowly dividing cells are more resistant because they have lower proliferative potential and greater capacity to cope with damage. So the statement that radiosensitivity increases with greater mitotic activity is the correct reflection of their observation. Tissue size is not the determining factor in this law.