Validation of MMP-9 antibody specificity for IHC studies. (A) Human colorectal carcinoma with intense cytoplasmic labeling of the cancer cells after incubating the section with MMP-9 primary antibody. (B) Adjacent section from the same colorectal tumor incubated with a non-immune serum that contains IgG (same isotype/ same species) showing complete lack of expression of MMP-9. (C) Benign myofibroblastoma of breast tissue and (D) Benign breast fibroadenoma do not express MMP-9. Magnification 20X (A-D).