Fig. 2From: Osteopontin regulates proliferation, apoptosis, and migration of murine claudin-low mammary tumor cellsImmunohistochemistry for OPN protein in (a, b) two independent PMT tumors and (c, d) two independent RST tumors. The brown staining indicates OPN protein which was expressed at only low levels in tumors cells of PMTs but at higher levels in the tumors cells or RSTs. RST tumors varied in histology with some tumors being composed primarily of spindle-shaped cells (c) and other tumors composed primarily of cells with squamous characteristics (d). Scale bars 100 μMBack to article page