First, I am SO sorry about your cousin's diagnosis and will be praying that she recovers well. I looked up the colors and here is a great site with all of them:
http://www.choosehope.com/category/b...or-cancer-type
I didn't know any of them except pink. It looks like Lung Cancer is "Clear and White" so I'm thinking any white would work....maybe some clear beads on center or something. OR Lavender is for ALL cancers so maybe lavender and white or even white with her favorite color. Whatever color you choose, I'm sure it will be breathtaking.