雅思阅读 124: Lung Cancer Hijacks the Brain

改编自 Scientific American 2026 年真实文章，去广告后按雅思阅读题型出题。

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Reading Passage

For years, scientists have viewed cancer as a localized glitch in which cells refuse to stop dividing. But a new study published in Nature suggests that, in certain organs, tumors actively communicate with the brain to trick it into protecting them.

Scientists have long known that nerves grow into some tumors, and that tumors containing lots of nerves usually lead to a worse prognosis. But they did not know exactly why.

Chengcheng Jin, an assistant professor of cancer biology at the University of Pennsylvania, and her colleagues discovered that lung cancer tumors in mice can use nerve endings to send signals to the brain through a complex neuroimmune circuit. They also confirmed the circuit exists in humans.

Setting up this circuit starts with a process called innervation, in which lung tumors wire themselves into the vagal nerves, the internal information highway that connects vital organs to the brain. Within this highway, the team identified a specialized group of sensory neurons that communicate directly with the central nervous system. "Our study suggests that the tumor actually hijacks these existing pathways to promote itself," explains Rui Chang, a co-author at the Yale School of Medicine.

When a tumor develops, it employs vagal neurons to send signals up to the nucleus of the solitary tract, a region in the brain stem that normally keeps blood pressure, heart rate and digestion in check. The signal sent by the tumor exploits this system, much like malicious code used by a hacker.

Instead of recognizing the tumor as an invader that needs to be destroyed, the brain processes the signal and activates the sympathetic nervous system, known as the driver of the fight-or-flight response. This causes the release of noradrenaline. In the context of cancer, this has catastrophic consequences.

The noradrenaline is released directly near the tumor, where it attaches to macrophages, the frontline immune cells that identify, eat and destroy threats. These macrophages have docking stations called beta-2 adrenergic receptors. When noradrenaline binds to these receptors, it reprograms the macrophages to switch sides.

In this suppressed state, the macrophages release chemical signals that act as a "do not disturb" sign for the rest of the immune system. This neutralizes T cells, the specialized assassins that normally kill tumor cells. Because the brain has ordered the macrophages to create an immunosuppressive shield, the T cells lose their energy, stop multiplying and fail to recognize the cancer as a threat.

"The authors characterized an entire bidirectional tumor-neural pathway that promotes tumor growth, with huge relevance to human health," says Catherine Dulac, a Harvard professor who was not involved in the study.

Jin and her team also looked for ways to stop tumors from talking to the brain. By mapping this loop from lung to brain and back, they identified several points where they could "cut the wire." Blocking any part of the circuit reawakened the immune system.

However, the researchers caution that translating these findings into human therapies is still far away. "What we are talking about is going from a mouse model to human. I think there is still a long way to go," Chang says.

Questions 1-5

Choose the correct letter, A, B, C or D.

1. What is the main finding of the study?

   • A. Cancer cells divide faster.
   • B. Tumors communicate with the brain to suppress immunity.
   • C. Nerves do not grow into tumors.
   • D. Cancer is purely a genetic disease.

2. What are the vagal nerves?

   • A. Nerves in the hands.
   • B. An information highway connecting organs to the brain.
   • C. Nerves in the skin.
   • D. The optic nerves.

3. What does the tumor signal cause the brain to release?

   • A. Insulin.
   • B. Noradrenaline.
   • C. Serotonin.
   • D. Dopamine.

4. What happens to macrophages when noradrenaline binds?

   • A. They attack the tumor.
   • B. They switch sides and suppress immunity.
   • C. They die immediately.
   • D. They multiply rapidly.

5. What does "cut the wire" mean?

   • A. Physically cutting the vagus nerve.
   • B. Blocking any part of the brain-tumor circuit to restore immunity.
   • C. Removing the tumor with surgery.
   • D. Killing all macrophages.

Questions 6-8

Do the following statements agree with the information given in the passage? Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

6. The researchers confirmed the circuit exists only in mice.
7. Macrophages normally identify and destroy threats.
8. Human therapies based on the findings are already available.

Questions 9-13

Complete the summary below. Choose ONE WORD ONLY from the passage for each answer.

Lung cancer tumors hijack the vagal nerves to send signals to the brain. The brain releases noradrenaline, which reprograms macrophages to suppress the immune system. This creates a shield that stops T cells from killing tumor cells. Blocking the circuit can reawaken immunity.

Answers

1. B
2. B
3. B
4. B
5. B
6. FALSE
7. TRUE
8. FALSE
9. vagal
10. noradrenaline
11. shield

Key Vocabulary

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