I've not had cancer, but my mother had breast cancer twenty years ago and I have had fourteen years' experience of living with serious illness myself. The last thing I'd want is a quilt reminding me of any illness. Creativity and beauty take me away from illness. If I were to make my mother a pink ribbon quilt, she would be absolutely appalled and deeply hurt. She was traumatised by the experience of cancer and had quite a lot of counselling to get over it, the last thing she'd want would be a constant reminder that would make any visitor to her home start asking her about something so private and painful.
Some people embrace the whole pink ribbon thing. If you refrain from using any breast cancer symbols, you won't offend them, it'll still be a lovely present. However, if you do use breast cancer symbols, you run a substantial risk of offending and upsetting your sister.
On the other hand, I gather you feel strongly about breast cancer awareness. Perhaps make a second quilt featuring this fabric and give it to a breast cancer charity for them to raffle off? That way, there will be money going to a good cause, and people will choose the quilt if it appeals to them. I'm doing a fairly explicit charity quilt myself right now: I wouldn't make it for someone specific unless I knew that they wanted that sort of thing, but for a raffle I reckon there will be enough people who will like it.