cancer
The word 'cancer' in French is used similarly to English, referring to the disease characterized by the development of abnormal cells. It is used in various contexts in the medical field and can refer to any type of cancer. Take note, it's pronounced ka(n)-sɛʁ in French.
I have cancer.
This is a straightforward statement where a speaker is conveying that they have cancer. In French, possession is often expressed with 'avoir' (to have), positioned before the thing being possessed, in this case cancer.
The fight against cancer is important.
In this sentence, we express the importance of combating a phenomenon or condition such as cancer. The use of the definite article 'le' before cancer is typical in French when speaking about general concepts or situations.
He makes a donation for cancer research.
This sentence pertains to someone offering a donation for a specific cause or purpose - in this case, the cause is cancer research. Note that 'faire un don pour' is a fixed expression that stands for 'making a donation for'. 'La recherche sur le cancer' means 'cancer research'.