A cluster of male breast cancer in office workers.

Three cases of male breast cancer were diagnosed among a small group of men who worked in a basement office of a multi-story office building. This office was adjacent to an electrical switchgear room which generated high magnetic fields in their work space. The risk of male breast cancer in this group was increased about 100-fold (observe three cases, expect 0.03 cases; P < 0.00001). Since 1991, 15 epidemiologic studies have associated male breast cancer with exposure to electromagnetic field.