Of the 80 specimens examined, the ‘high IDO expression’ (IDO2+ or 3+) were found in 37 (46%) cases, of which 25 (31%) were IDO2+ and 12 (15%) were IDO3+, IDO−, and IDO1+ tumours were found in 15 (19%) and 28 (35%) cases, respectively. This evidence concerns the gene IDO1 and neoplasm.