Effect of TIMP-1 on the plasmablastic differentiation of Burkitt lymphoma cells. Immunostaining panel shows down-regulation of germinal center marker CD10 (B) and up-regulation of the plasma cell marker CD138 (D) in TIMP-1JD38 tumor sections as compared with LXSN-JD38 control sections in panels A and C, respectively. Expression of CD30 (F) and CD44 (H) are also shown in TIMP-1⁺ tumors, whereas LXSN tumors are negative (E,G); original magnification × 400. (I) FACS analysis of integrin expression profile demonstrates down-regulation of β-1 (CD29), α-3, and CD49 on the cell surface of TIMP-1JD38 tumor cells as indicated in the histograms by a shift to the left of vertical bars by comparison with LXSN-JD38 control cells; no changes in the expression of other integrins are detected. Sections were examined under an Olympus BX41 microscope using UPLAN F1 40 ×/0.75 objective lenses. DAB shows specific staining in brown. Digital images were obtained with an Olympus DP12 (Olympus, Melville, NY) and imported with an Olympus Camedia USB Smartmedia card into AdobePhotoshop 7.0 (Adobe Systems, San Jose, CA) for processing.