Firstly, they say that "In fact, some types of cancer occur so often in people with AIDS that they are considered AIDS-defining conditions".
But that's only certain specific cancers. Then there are some other cancers that occur often with AIDS but are not "AIDS-defining".
And then there is the kicker: "Of course, as people with HIV are now living longer, they are also developing other cancers that are not clearly linked to HIV but are more common in older people, such as breast, colorectal, and prostate cancer.".
So, these cancers go up in AIDS survivors due to age, even though those people have immune systems that were already shot years before.
So much for a tidy hypothesis about aging -> lower immune system -> cancer, I suppose.
As for why those afflicted with AIDS get certain cancers, one explanation (also given in above page) is that some cancers are caused by viral infections. Weakened defense against viral infections, increased cancer of that type.
Here is a cancer.com (American Cancer Society) article on the relationship between AIDS and cancer.
Source: https://www.cancer.org/cancer/cancer-causes/infectious-agent...
Firstly, they say that "In fact, some types of cancer occur so often in people with AIDS that they are considered AIDS-defining conditions".
But that's only certain specific cancers. Then there are some other cancers that occur often with AIDS but are not "AIDS-defining".
And then there is the kicker: "Of course, as people with HIV are now living longer, they are also developing other cancers that are not clearly linked to HIV but are more common in older people, such as breast, colorectal, and prostate cancer.".
So, these cancers go up in AIDS survivors due to age, even though those people have immune systems that were already shot years before.
So much for a tidy hypothesis about aging -> lower immune system -> cancer, I suppose.
As for why those afflicted with AIDS get certain cancers, one explanation (also given in above page) is that some cancers are caused by viral infections. Weakened defense against viral infections, increased cancer of that type.