Myeloperoxidase+ (MPO+) neutrophils and CD11b+Ly6G+ MDSCs infiltration into tumours is reduced in CXCR2 knockout PKF [mice with conditional KrasG12D mutation and knockout of TGF-β receptor type II (Tgfbr2), (LSL-KrasG12D/+; Tgfbr2flox/flox, Ptf1a-Cre] mice compared to control animals (185). The gene discussed is MPO; the disease is neoplasm.