Microarray analysis specifically noted increased interleukin (IL)-1α and inducible nitric oxide synthase (iNOS levels) (12), both involved in signalling pathways that promote tumour growth and a raised IL-1α level was shown to be a poor prognostic factor in gastric cancer and squamous cell carcinoma affecting the head and neck (18, 19). This evidence concerns the gene NOS2 and squamous cell carcinoma.