The protective role of MyD88 and TLR2 and TLR9 in irinotecan-induced mucositis was associated with a pronounced reduction of the local inflammatory reaction, as detected by the measurement of myeloperoxidase activity (Fig 5A, 5C and 5E) and COX–2 (Fig 5B, 5D and 5F) and IL–1β production (Fig 6A, 6C and 6E). This evidence concerns the gene TLR9 and mucositis.