NPR explores how certain diseases, such as cancer, particularly breast cancer, turn from a medical condition that no one talked about to a prominent social cause. Some of the factors, according to the article, that helped cancer become a visible concern:

[T]he women’s health movement, the rise of information technology and a shift in the medical culture itself away from a purely hierarchical system in which doctors were always assumed to know best…

A lot of illness-awareness promotion, though, stems from the way AIDS patients responded to the rise of that disease…The tropes developed with AIDS — clothing accessories such as ribbons, displays of commemorative quilts, marches on Washington — have all since been adopted by groups concerned with other conditions.

How certain issues (and not others) become social problems is often a fascinating tale. What one time period and culture sees as problematic is not an issue for the same culture in a later period – Prohibition would be a great example. There is often a complicated process that takes place by which the problem is brought to the attention of the public and then people become convinced it is a cause that requires their action.