Andie, I think I can safely tell you not to worry. The breast cancer/antiperspirant link has never been proven; it falls into that category of "SOMETHING might have given you breast cancer and it might have been an environmental factor and we know aluminum is in antiperspirants and we think it might cause Alzheimer's and what if it also causes breast cancer..." In other words, it's too long a trail to follow. If you think you have breast cancer symptoms, don't spend time worrying about why — put your energy towards making a doctor's appointment and getting yourself checked out. If you were just worrying in advance, due to having used men's antiperspirant — stop worrying. And to set your mind fully at ease, choose an all-natural deodorant, rather than an antiperspirant, OK? Good luck - PJH