Which of these properties is found only in cancer cells?

• A. Ability to undergo mitosis
• B. Ability to grow without external growth signals
• C. Containment of DNA
• D. Presence of a nucleus

Answer: (B)

Verified step by step guidance

1. Understand the context of the question: Cancer cells are abnormal cells that exhibit specific properties distinguishing them from normal cells. The question asks for a property unique to cancer cells.
2. Review the options provided: (1) Ability to undergo mitosis, (2) Ability to grow without external growth signals, (3) Containment of DNA, and (4) Presence of a nucleus.
3. Analyze each option: (1) Normal cells also undergo mitosis as part of their cell cycle, so this is not unique to cancer cells. (2) Cancer cells can grow and divide without external growth signals, which is a hallmark of cancer. (3) Both normal and cancer cells contain DNA, so this is not unique. (4) Both normal and cancer cells have a nucleus, so this is not unique.
4. Focus on the hallmark of cancer: Cancer cells bypass the normal regulatory mechanisms that require external growth signals for cell division. This ability to grow autonomously is a defining characteristic of cancer cells.
5. Conclude that the correct answer is 'Ability to grow without external growth signals,' as this property is unique to cancer cells and distinguishes them from normal cells.