Interestingly, these signaling pathways have been reported to be modulated by a natural non-toxic agent, 3, 3-diindolylmethane (DIM) [7]–[9] which raises the possibility that combination of DIM with Herceptin might help to enhance the antitumor activity of Herceptin against HER-2/neu-expressing breast cancer. Here, ERBB2 is linked to breast cancer.