Case Study:

In 2025, a 45-year-old patient named Rajesh from Delhi was diagnosed with Stage II lung cancer after prolonged symptoms of chronic cough and weight loss. Medical reports showed uncontrolled division of lung epithelial cells due to mutations in tumor suppressor genes such as p53. Doctors at a government cancer institute recommended a combination of chemotherapy and targeted immunotherapy.

Rajesh’s treatment plan included 6 cycles of chemotherapy drugs administered every 21 days. Each cycle aimed to destroy rapidly dividing cancer cells, but it also affected normal cells, causing side effects like hair loss and reduced immunity. Alongside this, immunotherapy was introduced to enhance his immune system’s ability to recognize and attack cancer cells.

After 3 months, tumor size reduced by approximately 40%, as confirmed by CT scans. However, doctors had to carefully balance treatment dosage to avoid damage to healthy tissues. Financial constraints also influenced treatment decisions, as immunotherapy costs were significantly higher than conventional methods.

This case highlights the biological basis of cancer (loss of cell cycle control), the principle of selective toxicity in treatments, and the challenges in real-world cancer management in India, including affordability and accessibility.

Questions:

Section A - MCQs

1. Why does chemotherapy affect both cancerous and normal cells?

A. It targets only mutated DNA
B. It attacks all rapidly dividing cells
C. It destroys only immune cells
D. It works only in lungs

2. The role of p53 gene in normal cells is to:

A. Promote uncontrolled cell division
B. Inhibit DNA replication
C. Regulate cell cycle and apoptosis
D. Produce antibodies

3. Immunotherapy is preferred in some cases because it:

A. Directly kills all body cells
B. Boosts immune system to target cancer cells
C. Stops oxygen supply to tissues
D. Replaces damaged DNA

4. A major challenge in cancer treatment in India highlighted in the case is:

A. Lack of doctors
B. Excessive availability of drugs
C. High cost of advanced therapies
D. Absence of hospitals

Section B - Short Answer Questions

1. Explain why cancer is considered a disease of the cell cycle.

2. Compare chemotherapy and immunotherapy based on their mechanism of action. 

3. Why is dosage regulation important during cancer treatment? 

Section C - Long Answer Question

1. Suppose Rajesh’s cancer cells developed resistance to chemotherapy.

• Explain how resistance occurs.
• Suggest alternative treatment strategies.
• Evaluate which therapy would be most effective and why. 

Answer Key:

MCQs:

1. B
2. C
3. B
4. C

Short Answers:

1. Cancer involves loss of control over the cell cycle due to mutations in regulatory genes. Cells divide uncontrollably, forming tumors.

2.

• Chemotherapy: Uses chemicals to kill rapidly dividing cells (non-specific).
• Immunotherapy: Enhances immune system to specifically target cancer cells.

3. Proper dosage prevents excessive damage to normal cells and reduces severe side effects while ensuring effectiveness against cancer cells.

Long Answer:

Resistance Explanation:
Cancer cells may mutate further, altering drug targets or increasing drug efflux, reducing chemotherapy effectiveness.

Alternative Treatments:

• Immunotherapy
• Targeted therapy
• Radiation therapy

Evaluation:
Immunotherapy may be more effective as it adapts with the immune system and provides targeted action with fewer side effects.