Question

What is the role of the p53 gene in cancer development.

• A. Promoting cell division
• B. Suppressing angiogenesis
• C. Inducing cell cycle arrest and apoptosis
• D. Enhancing DNA replication

Hint:

Think of p53 as a cellular checkpoint manager. When it detects a problem (like DNA damage), it gives the cell a choice: "stop and repair" (cell cycle arrest) or "self-destruct" (apoptosis). If p53 is mutated, this manager is gone, and damaged cells can continue to divide, leading to cancer.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The p53 gene is a crucial tumor suppressor gene, often referred to as the "guardian of the genome." Its primary role is to prevent cells with damaged DNA from proliferating, thus preventing the accumulation of mutations that can lead to cancer.
Step 2: Detailed Explanation:
When a cell experiences stress, such as DNA damage or oncogene activation, the p53 protein is activated. Once active, it functions as a transcription factor, initiating several protective responses:
Cell Cycle Arrest: p53 can halt the cell cycle, typically at the G1/S or G2/M checkpoints. This provides the cell with time to repair the DNA damage before it proceeds with DNA replication or division.
Apoptosis (Programmed Cell Death): If the DNA damage is too severe to be repaired, p53 triggers the intrinsic pathway of apoptosis. This eliminates the potentially cancerous cell, preventing it from passing on its mutations.
Other Roles: p53 is also involved in other anti-cancer processes, including suppressing angiogenesis (the formation of new blood vessels that tumors need to grow) and regulating cellular metabolism.
Comparing these functions to the options:
(1) and (4) describe the functions of oncogenes, which promote cancer. p53 does the opposite.
(2) is a correct function of p53, but it is a secondary role compared to its primary function.
(3) describes the two most central and critical functions of p53 in preventing cancer. The loss of these functions is a key step in the development of many human cancers.
Step 3: Final Answer:
The primary and most well-known role of p53 in preventing cancer development is to respond to cellular stress by inducing cell cycle arrest and apoptosis.