Growth inhibition (GI) is a medical term pertaining to cancer therapy and the specific reduction in growth of tumors and oncogene cells by a chemical compound, mechanical therapy (e.g. electroporation), radiation, gene therapy, protein therapy,Protein Therapy ultrasound waves, light, or any other treatment.human disease | Definition & Facts | Britannica.com Measured in micromoles/liter or micrograms/liter. See also Chemotherapy Radiotherapy Cancer Oncology Electroporation Protein therapy Sources