Women who are current smokers or have smoked for at least 10 years have an approximately 10% increased risk of developing breast cancer.66-68 The transport of tobacco-derived carcinogenic chemicals to breast tissue is believed to contribute to oncogene and tumor suppressor gene alterations, especially involving TP53. Both active and passive smoking have been implicated in pro-carcinogenic events. The gene discussed is TP53; the disease is breast carcinoma.