Histological characterization of mammary tumors.

<p>A, C, E, immunohistochemical staining for lipocalin-2 in mammary tumor in (A) <i>PyMT, Lcn2</i>+/+ mouse, (C) <i>PyMT, Lcn2</i>−/−, and (E) <i>PyMT, Lcn2</i>+/+ mouse as negative control, where no primary antibody was added. B, D, F, immunohistochemical staining for MMP-9 in mammary tumor in (B) <i>PyMT, Lcn2</i>+/+ mouse, (D) <i>PyMT, Lcn2</i>−/−, and (F) <i>PyMT, Lcn2</i>+/+ mouse as negative control, where no primary antibody was added. Original magnification x600. G, H+E staining of tumor from a <i>PyMT, Lcn2</i>+/+ mouse representing largest metastasis volume. F, H+E staining of tumor from <i>PyMT, Lcn2</i>−/− mouse representing largest metastasis volume. In both G and F strongly atypical tumor cells with numerous mitoses are seen, and surrounded by slender strands of collagen tissue. Original magnification x630. Abbreviations: <i>PyMT: MMTV-PyMT</i>.