Epidemiological indicate that that the high consumption of tomatoes, which are rich in lycopene, reduces the risk of reactive oxygen species mediated diseases such as cancer. Lycopene has been shown to prevent chemically-induced DNA damage [3]. Treatment of cultured human liver cells with lycopene significantly reduced DNA damage induced by hydrogen peroxide or n-nitrosodiethylamine. Lycopene was more protective when added before the treatment with the carcinogens.
Methylation of genes may be a factor in carcinogenesis as increased genome-wide methylation can lead to mutation. Therefore the methylation state of some genes can be used as a biomarker for tumorigenesis. For example, hypermethylation of the glutathione S-transferase gene appears to be a possible diagnostic indicator of prostate cancer.[1] One in-vitro study showed that lycopene has a direct DNA demethylating activity at dietary relevant concentrations. Lycopene partially demethylated the promoter of a tumor suppressor gene (GSTP1) in breast cancer cells. These cancer cells lack the ability to produce this gene, but after treatment with lycopene this ability was restored [2].
[1] Nakayama M, Gonzalgo ML, Yegnasubramanian S, Lin X, De Marzo AM, Nelson WG. "GSTP1 CpG island hypermethylation as a molecular biomarker for prostate cancer". J. Cell. Biochem. 91 (3): 540–52.
Environ Mol Mutagen. 2008 Jan;49(1):36-45.
[2] King-Batoon A, Leszczynska JM, Klein CB. "Modulation of gene methylation by genistein or lycopene in breast cancer cells." Oral Health Prev Dent. 2007;5(4):327-36.
[3] Scolastici C, Alves de Lima RO, Barbisan LF, Ferreira AL, Ribeiro DA, Salvadori DM. "Antigenotoxicity and antimutagenicity of lycopene in HepG2 cell line evaluated by the comet assay and micronucleus test." Toxicol In Vitro. 2008 Mar;22(2):510-4.
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