Breast cancer is not contagious. Infectious diseases have their natural characteristics. For instance, respiratory infectious diseases and even hepatitis can be transmitted through certain pathways. Cancer, including breast cancer, is not communicable. To date, medical research has found no evidence suggesting that cancer can be spread from person to person. Only about 5% of cancers have a genetic component. Consider this: if cancer were contagious, wouldn't medical professionals, aside from the patients' families, be the most affected group? However, how many health care providers have contracted cancer from their patients? Thus, it can be stated that breast cancer is not contagious.