Which statement about the Bergonie and Tribondeau law is NOT correct?

• A. Radiosensitivity depends on the degree of mitotic activity in tissue
• B. Radiosensitivity depends on the age of the individual cells
• C. Radiosensitivity depends on the number of undifferentiated cells in tissue
• D. Radiosensitivity depends on the length of time the cells stay in active proliferation

Answer: (B)

The key idea here is that radiosensitivity is governed by cellular characteristics: how undifferentiated the cells are, how actively they divide, and how long they remain capable of proliferation. Bergonie and Tribondeau state that tissues with many undifferentiated cells, high mitotic activity, and a long remaining proliferation period are more radiosensitive. The statement about the age of individual cells isn’t part of this framework—the age of a cell does not determine its radiosensitivity in this law. In other words, a cell’s differentiation level and its ongoing ability to proliferate drive sensitivity, not how old the cell happens to be. The other factors described—degree of mitotic activity, number of undifferentiated cells, and length of active proliferation—are all consistent with the law and explain why those aspects increase radiosensitivity.