What is Loss of Imprinting?
Genomic imprinting is a rare but important mechanism of gene regulation where one copy of the gene (an “allele”) is normally expressed and the other allele is silenced through epigenetic marks of parental origin.14 For example, the imprinting of a gene can be maternal, resulting in the expression of the paternal allele and silencing of the maternal allele. IGF2 is normally imprinted in human tissues. In 1993, scientists at the Johns Hopkins University School of Medicine discovered that normally imprinted genes including IGF2 can “lose their imprint” resulting in the expression of both copies of the gene, and this can lead to human disease.13 IGF2 is a growth promoting gene, and evidence is mounting that individuals whose peripheral blood leukocytes (“PBL”) exhibit loss of imprinting of IGF2 (the IGF2 Biomarker) may be at elevated risk for developing colorectal cancer.
