New Science eTextbook 4A (UPC)

7 Why do we have cancer? How can we prevent it? 1. Cancer is not an infectious disease, but it can be deadly. Look at how cancer develops.

cancer cell

abnormal cell

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2

normal cell

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Normal cells keep the body functioning properly (fig 1 ). Abnormal cells divide and grow uncontrollably (fig 2 ), forming a tumour in the body. A harmful tumour is called cancer (fig 3 ). Cancer cells may spread to other organs, affecting the functioning of normal cells and organs, threatening our life.

2. Cancer can develop in different parts of the body. The symptoms can be different. What are the common symptoms of cancer?

Common symptoms of cancer

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long-term unexplained tiredness

lumps on the body

unexplained weight loss

Symptoms of specific cancers

Cancer patients may suffer a lot after treatment. We should care for them.

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a sudden change in toilet habits

a change in moles

long-term coughing

colorectal cancer

skin cancer

lung cancer

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Source: Cancer Online Resource Hub, HKSAR Government

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