Earlier quoted context omitted.
Besides cancer isn't really "a disease" but rather "a family of diseases" that can vary a lot. Even breast cancer can be one of many different cancers. It's like saying "we'll cure infectious diseases"
"Cancer isn't a single disease" is often shouted from the Dunning-Kruger peak of cancer research. I think it was popularized by an explainer video on Youtube, and now it's being memed. The people who think this way want to legitimize funding a particular research niche that they benefit from. A more sophisticated view is that cancer (one idea) is an problem of rates (like most things in biology) and there is a tumor…
Literally first phrase on Cancer Wikipedia entry.... [1]
"Cancer is a group of diseases involving uncontrolled cell growth typically resulting in tumors with the potential to invade or spread to other parts of the body...."