Cancer Cells and Checkpoints?

📌 CONCEPT: Cancer cells exploit the G1 checkpoint by disrupting the normal regulation of cell division, allowing them to continue proliferating uncontrollably.

📐 RULE / FORMULA: The G1 checkpoint's primary function is to ensure that the cell has sufficient resources and DNA integrity before progressing to the S phase.

💡 WORKED EXAMPLE: Imagine a normal cell at the G1 checkpoint, where it assesses its growth status and DNA integrity. A cancer cell, however, may bypass this checkpoint by mutating genes involved in the G1-S transition, such as p53, leading to uncontrolled cell division. This impairs the cell's ability to stop proliferating in response to DNA damage.

⚠️ COMMON MISTAKE: Students often misunderstand the G1 checkpoint as a mechanism that entirely prevents cell division, rather than a regulatory step that ensures the cell's readiness for DNA replication.