Targeted nutrigenomics as a means of breast cancer management: from DNA methylation to microRNAs

Breast Cancer (BC) is the most prevalent cancer affecting females and the leading cause of death around the world. The World Health Organization (WHO) has announced that the incidence of BC increases approximately 1.8-2 % annually. Hence, it is important that new prevention and treatment strategies involving epigenetics and nutrigenomics are explored. Epigenetics refers to potential changes in gene expression and chromatin structure without alteration of DNA sequence, but still modulates the expression of a particular phenotype. Nutrigenomics determines the effect of dietary habits on cancer risk and tumor behavior, both in progression and inhibition of cancer. The modulation of chromatin structure is an essential component in the regulation of transcriptional activation and repression. Therefore, identifying the regulators of gene expression changes during cancer progression is essential for early diagnosis and inhibition of this malignancy. The methylation of promoter genes, as well as the interplay between microRNAs (miRNAs) and messenger RNAs (mRNAs) of target genes, is the primary component of epigenetics. Any defect in these processes is considered a crucial mechanism for gene and pathway dysregulation in all human cancers, including BC. Nutritional genomic and epigenetic mechanisms may play a pivotal role in prevention as well as early diagnosis of BC, especially for closely related female family members of BC patients. It seems cytosine methylation in Cytosine-phosphate-Guanine dinucleotide (CpG) Islands reflects changes in balance tissues rigidity. Hypo- and hypermethylation of CpG Islands (CGIs) play a crucial role in development of BC via up-regulation of oncogenes and down-regulation of tumor suppressor genes (TSGs). These could be the most effective mechanisms to distinguish BC from other types of cancer. beneficial effects of some nutritional components on the function and structure of non-coding RNA and DNA methylation. We also discuss the role of nutrigenomics as a non-invasive method to explore the epigenetic mechanisms involved in BC and also in the prevention, treatment, early diagnosis, and distinguishing a variety of cancers from each other. In addition, the importance of non-coding RNAs, including miRNAs in body fluids, also need to be further clarified.