CD44 silencing in 143-B OS cells reduced the density of proliferating cells in intratibial primary tumors and decreased the content of the tumor suppressor merlin in primary tumors and pulmonary metastases to immunohistochemically nearly undetectable levels.

<p>Representative images of 6 µm paraffin sections of primary tumor (PT) (panels A-C and G-I) and of lung tissue with pulmonary metastases (PM) (panels D-F and J-L) stained for the proliferation marker Ki67 (panels A-F) and for merlin (panels G-L). Tissues were collected at sacrifice from SCID mice intratibially injected with 143-B EV (EV), 143-B Ctrl shRNA (Ctrl shRNA) or 143-B shCD44 (shCD44) cells. Bars, 100 µm.