TESTING THIS GENE REQUIRE PRE AND POST GENETIC COUNSELING
The TOX3 gene encodes a protein that contains an HMG-box (high mobility group box) is a protein domain which is involved in DNA binding. The C-terminus of the encoded protein is glutamine-rich due to CAG repeats in the coding sequence. A minor allele of this gene has been implicated in an elevated risk of breast cancer.
Research into this gene has shown that when hypermethylated it can play a role in breast cancer etiology. Hypomethylation occurs when there are more methylated cytosines than normal. This can result in less transcription of the gene.
Dietary polyphenolic compounds have been reported to have many interesting biological activities such as preventing hypermethylation. EGCG, the major polyphenolic compound in green tea, inhibits DNA methyltransferase (DNMT). Treatment of cancer cells with EGCG caused the demethylation of the CpG islands in the promoter regions and the reactivation of methylation-silenced genes such as TOX3.
Genetic variations in this gene should also take into account your FGFR2, BRCA1, and BRCA2 genotypes to determine risk for breast cancer.