MMP8 and leukemia: A consistent finding in the two leukemia-responsive neutrophil subgroups, which show increased levels in response to the presence of leukemic cells, was high-level expression of specific MMPs. Of the 24 MMP genes in the mammalian genome, only Mmp8, 9 and 25 were expressed in the Ly6g + and Camk1d + neutrophils, all of which were down regulated during maturation as shown in the pseudotime analysis.