To systematically analyze changes in expression patterns of cathepsin B and L in myeloid cell populations at different stages of carcinogenesis, we used both KC and KPC mice, with KC mice genetically and histologically recapitulating pre-invasive pancreatic intraepithelial precursor lesions (PanIN) and KPC mice genetically resembling invasive cancers that histologically evolve sequentially from pre-invasive PanIN lesions. This evidence concerns the gene CTSB and cancer.