Answer: Loss-of-function mutations in Rb protein, leading to uncontrolled cell cycle progression
Rationale: The retinoblastoma (Rb) protein is a crucial growth suppressor that regulates the cell cycle. A loss-of-function mutation in Rb leads to loss of control over cell cycle progression, enabling cancer cells to “evade growth suppressors.”
Rb normally functions to control whether E2F is able to induce transcription – if Rb is bound to E2F, then E2F isn’t functional. In the case of mutations to Rb, the ability of the protein to bind E2F is lost, so E2F becomes active when it shouldn’t be.
Q9 During the treatment of a cancer, a patient develops resistance to multiple chemotherapy agents. Which hallmark of cancer is most likely contributing to this phenomenon, and what mechanism is involved?
LaNts and Laminins 