Methods and devices for the regulation of gene expression by cells via the application of fields generated by specific and selective electric and electromagnetic signals so as to target diseased or injured tissue for treatment. By gene expression is meant the up regulation or down regulation of the process whereby specific portions (genes) of the human genome (DNA) are transcribed into mRNA and subsequently translated into protein. Methods and devices are provided for the targeted treatment of injured or diseased tissue that include providing specific and selective electric and electromagnetic signals and exposing tissue to the fields generated by the signals so as to regulate gene expression. In particular, methods and devices are provided for the targeted treatment of bone defects, osteoarthritis, osteoporosis, cancer, and other disease states.