Regarding the presence of neutrophils in HNSCC, Trellakis et al. studied infiltration of polymorphonuclear granulocytes (PMNs) in tumors in the oropharynx (n = 71) and hypopharynx (n = 28) by staining for cells expressing the granulocytic marker CD66b or the azurophilic granule marker myeloperoxidase (MPO) [21]. The gene discussed is MPO; the disease is head and neck squamous cell carcinoma.