Epigenomics is the study of the complete set of chemical modifications on the DNA and histone proteins that regulate gene activity without altering the underlying DNA sequence. These modifications can influence how genes are turned on or off, affecting cellular functions and development. The field of epigenomics explores how environmental factors, lifestyle choices, and experiences can lead to changes in these chemical markers. This research has implications for understanding various diseases, including cancer, and may help in developing targeted therapies and personalized medicine approaches.