In the USA prostate cancer is one of the most common cancers in men and the second leading cause of cancer-related deaths. Epidemiological and dietary studies have shown a link between high dietary intake of cruciferous vegetables and decreased prostate cancer risk. A study conducted by Technion Israel Institute of Technology (Haifa) showed that indole-3-carbinol had a significant inhibitory effect on prostate cancer cells in vitro and in vivo and concluded that this phytochemicals is a potential candidate as both preventive and therapeutic agent for humans . The researchers tested the effect of indole-3-carbinol on the growth of prostate cancer cells inoculated subcutaneously in mice. They found that the administration of indole-3-carbinol significantly reduced cells proliferation and promoted the apoptosis of the prostate cancer cells. Fan S and co-workers of the Georgetown University (New York) reported that both indole-3-carrbinol and genistein target the breast cancer susceptibility genes in both prostate and breast cancer cells . The breast cancer susceptibility genes are responsible for the suppression of tumor growth, not only of breast cancer cells but also ovarian and prostate cancer cells. This in-vitro study showed that the phytochemicals induced the expression of these genes.
Another study found that injected indole-3-carbinol has anti-prostate cancer activity in rats . Both intraperitoneal (in the body cavity) and intravenous injection of the phytochemical inhibited the growth, incidence and metastases of prostate cancer cells which were injected in rats.
A study conducted at the Wayne State University School of Medicine, Detroit, concluded that indole-3-carbinol and its metabolite diindolylmethane are candidates for the prevention and the treatment of prostate cancer . The researchers confirmed that indole-3-carbinol and diindolylmethane upregulate the expression of phase I and phase II enzymes, which are involved in the detoxification and inhibition of carcinogens. Both phytochemicals regulate many genes that are important for the control of cell cycle, cell proliferation, signal transduction, and other cellular processes.
A study conducted by the Long Island Jewish Medical Center, New York, suggested that indole-3-carbinol may be an effective sensitizer of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment against TRAIL-resistant prostate cancer cell lines . TRAIL is a ligand molecule which induces the process apoptosis in a variety of transformed cells including prostate cancer cells but has no effect on normal cells. The researchers, led by Jeon KI, tested the potential sensitizing effects of indole-3-carbinol on TRAIL-mediated apoptosis in a prostate cancer cell line.
They found that the phytochemical enhanced TRAIL-mediated apoptosis and that the apoptosis was the result of increased levels of two trail death receptors.
 Indole-3-carbinol (I3C) exhibits inhibitory and preventive effects on prostate tumors in mice. Food Chem Toxicol. 2008 Mar;46(3):863-70.
 BRCA1 and BRCA2 as molecular targets for phytochemicals indole-3-carbinol and genistein in breast and prostate cancer cells. Br J Cancer. 2006 Feb 13;94(3):407-26.
 Anti-carcinogenic and anti-metastatic properties of indole-3-carbinol in prostate cancer. Oncol Rep. 2005 Jan;13(1):89-93.
 Indole-3-carbinol and prostate cancer.J Nutr. 2004 Dec;134(12 Suppl):3493S-3498S.
Sarkar FH, Li Y.