The utility of breastmilk for genetic or genomic studies: a systematic review

This study synthesized scientific literature that applies genetic or genomic approaches to breastmilk. A literature search of PubMed was conducted in March 2012 using the key words "breast milk," "lactation," "genetic," "gene expression," and "epigenetic." Additional articles were identified/selected for evaluation with MeSH term searches, and a review of article reference lists was obtained from the search. The initial 657 abstracts retrieved from the literature search were reviewed, and 16 studies were selected for evaluation. Studies that examined the transmission of viruses/bacteria into breastmilk and/or measured concentration of specific proteins without examination of genetic material from milk were excluded. Data related to subjects, tissue, purpose, setting, gene/protein, approach (candidate versus genome-wide), platform, statistical analysis, and results were extracted. Gene expression and epigenetic/epigenomic study designs have been successfully implemented using breastmilk. A major weakness of both gene expression studies and epigenetic studies that examine breastmilk is the omission of maternal information known to influence milk composition. This review article is the first to synthesize evidence related to the application of breastmilk to evaluate RNA and epigenetic modifications. Additional research is needed that applies epigenetic analyses to human breastmilk samples. Findings from this review can be used for future research designs that use breastmilk for genetic analyses.