I'm so glad you posted this. I haven't been diagnosed with breast cancer yet, but I do have a large papilloma in my right breast that will be excised next month. The tissue will be sent to pathology to determine whether the papilloma is mixed with or is "hiding" malignant cells. I also have strong b.o. only in my right armpit along with occasional tingling and episodic pain in that breast and armpit that sometime radiates down the arm. The underarm odor is the most persistent symptom. Showering does not wash it away. The only way I've been able to control the odor is with vigorous washing followed by wiping my armpit with alcohol swabs before putting on deodorant. I am also aware of animals being able to smell cancer and wondered if some humans could too, so this post really caught my interest. My husband can also smell the difference between my right and left underarm odors.