n.

1. 癌，惡性腫瘤；癌症[C][U]
   The doctors are making an attempt to prevent cancer cells spreading.

   醫生們試圖阻止癌細胞擴散。

2. （社會等的）弊端，痼疾，病根[C]
   What was happening was a sickness, a cancer in society that could not be helped.

   所發生的一切是種病態，一種無可救藥的社會弊病。

3. （大寫）巨蟹星座[C]；巨蟹座

n.

1. a disease caused by an uncontrolled division of abnormal cells in a part of the body.
   ▸a malignant growth or tumour resulting from such a division of cells.
2. something evil or destructive that is hard to contain or eradicate:
   the cancer of racism.