Occurrence, Role, and Challenges of MicroRNA in Human Breast Milk: A Scoping Review

MicroRNAs are non-coding segments of RNA involved in the epigenetic modulation of various biological processes. Their occurrence in biological fluids, such as blood, saliva, tears, and breast milk, has drawn attention to their potential influence on health and disease development. Hundreds of microRNAs have been isolated from breast milk, yet the evidence on their function remains inconsistent and inconclusive. The rationale for the current scoping review is to map the evidence on the occurrence, characterization techniques, and functional roles of microRNAs in breast milk. The review of the sources of this evidence highlights the need to address methodological challenges to achieve future advances in understanding microRNAs in breast milk, particularly their role in conditions such as neoplasms. Nonetheless, remarkable progress has been made in characterizing the microRNA profiles of human breast milk.