This tidbit is from Utne magazine:

Fed up by the soft-focus, “very pink ribbons and angels” aesthetic of many cancer support groups, Angela Allen came up with Cranky Chick Chemo Caps — knit hats branded with militant slogans like “FUCK CANCER” and “CHEMO SUCKS,” reports Bust (Summer 2003). When Sharon Osbourne of the famous TV family was photographed wearing one of the caps to her own chemo treatments, Allen was flooded with requests. She still makes all the caps by hand and donates 10 percent of the profits to the Breast Cancer Action organization. Allen’s hats can be ordered at Deviant Goods.

Allen states on her site that the hats are reversible so “if you don’t want the text to show, just flip the whole hat inside out. Voila! Now you’re cranky on the inside, but won’t offend your parents on the outside.” And you don’t have to have cancer to buy a hat; you can wear one to show support for a loved one doing battle with the illness.