The oropharyngeal aerobic gram-negative bacillary carriage, uncommon in healthy people, is high in patients with head and neck cancer. A marked increase in oral Gram-negative enterobacteria and pseudomonads has particularly been shown during the period of radiation therapy. Irradiation-induced oral mucositis in patients with cancer of the head and neck is associated with changes in this oropharyngeal microflora, but this change is very unlikely to be a causative one. The aim of the study was to ascertain whether there was any change in the Gram positive and Gram negative oropharyngeal flora and to objectively determine whether these bacteria could play a role in the causation of irradiation mucositis.

Gene therapy potentially represents one of the most important developments to occur in the field of medicine. Gene therapy is an experimental technique that uses genes to treat or prevent diseases. This technique may allow doctors to treat a disorder by inserting a gene into a patient's cells instead of using drugs or surgery. As gene therapy has moved from the laboratory into the clinic, several issues have emerged as central to the development of this technology: gene identification, gene expression and gene delivery.