Question

Choose correct statements about cancer cells.
A. They disobey the growth controlling signals in the body.
B. They escape death signals and achieve immortality.
C. They do not lose properties of differentiation.
D. Due to gain of growth controls, they are genetically stable.
Choose the correct answer from the options given below :

• A. A and C Only
• B. B and D Only
• C. A and B Only
• D. C and D Only

Hint:

Review the "Hallmarks of Cancer" by Hanahan and Weinberg. Key features include: Evading apoptosis, self-sufficiency in growth signals, insensitivity to anti-growth signals, tissue invasion/metastasis, limitless replicative potential, and sustained angiogenesis.

Answer 1

The Correct Option is C

Step 1: Concept:
The question tests fundamental knowledge regarding the hallmarks and pathological characteristics of malignant cancer cells.

Step 2: Step-by-step Explanation:

• Statement A: Normal cells require external mitogenic signals to divide and halt division upon receiving contact inhibition or anti-growth signals. Cancer cells acquire mutations (e.g., in oncogenes or tumor suppressor genes) that allow them to autonomously sustain proliferative signaling. They effectively disobey systemic growth-controlling signals. Thus, Statement A is True.

• Statement B: Apoptosis (programmed cell death) is a natural safeguard against damaged cells. Cancer cells frequently mutate pathways (like the p53 tumor suppressor pathway) to evade these apoptotic death signals. Furthermore, they often upregulate the enzyme telomerase, which maintains telomere length, conferring unlimited replicative potential (immortality). Thus, Statement B is True.

• Statement C: Normal cells are highly specialized (differentiated) to perform specific physiological functions. As cancer cells progress, they typically undergo 'anaplasia' or dedifferentiation, losing their specialized features to become more primitive and exclusively focused on rapid replication. Therefore, they do lose properties of differentiation. Thus, Statement C is False.

• Statement D: Cancer cells are characterized by a profound loss of growth control, not a gain. This rampant, unchecked division combined with defective DNA repair mechanisms leads to massive genomic instability, rampant mutations, and chromosomal abnormalities. They are highly genetically unstable. Thus, Statement D is False.

• The only true statements are A and B.

Step 3: Final Answer:
Since only A and B correctly describe cancer hallmarks, Option (C) is the right choice.