Indole-3-carbinol (precursor to DIM) and sulforaphane.
This is the number one cancer-fighting phytochemical with fabulous research behind it, found in cruciferous vegetables which include broccoli, cauliflower, Brussels sprouts, cabbage, collard greens, kale, bok choy, arugula, horseradish, radishes, watercress, daikon, kohlrabi, mustard greens and rutabaga.