CD68 and neoplasm: Thus the expression of IL-33 by the tumours diminished the accumulation of immune suppressive cells and promoted elevated numbers of infiltrating CD68+ tumour-associated macrophages (Fig. 2i,j,k,l) and neutrophils (Fig. 2m,n,o,p) in the metastatic IL-33-expressing tumours compared to unmodified metastatic tumour.