Correlation of TIMP-1 expression with plasmacytic phenotype. Immunohistochemistry of a normal reactive follicle demonstrates expression of TIMP-1⁺ cells in the light zone (A); original magnification × 100. Detailed TIMP-1 expression in the cytoplasm of differentiated B cells in the light zone (B); original magnification × 1000. Expression of TIMP-1 in primary tumors. Follicular-center lymphoma (C) and a Burkitt lymphoma (D) do not express TIMP-1; bona fide normal plasma cells are positive in these tumors. Myeloma cases (E-F) demonstrate TIMP-1 overexpression by the majority of tumor cells, with higher expression in panel F and lower TIMP-1 expression in panel E; original magnification × 400. (Image acquisition procedures described in Figure 4 apply.) (G) Western blots demonstrate TIMP-1 (30 kD) expression in different lymphoma cell lines. The y-axis of the graph shows relative density of TIMP-1 versus β-actin bands. A significant difference is noted between the lymphoma cell line group and the cell line group of myelomas and primary effusion lymphomas (PELs; P < .005). Mantle cell lymphomas: NCEB, Granta (lanes 1 and 2); follicular lymphomas: SUDHL-4, SUDHL-5, SUDHL-6 (lanes 3-5); Burkitt lymphomas: Ramos, JD38, BL-41 (lanes 6-8); multiple myelomas: KMM-1, KMS-11, KMS-12BM, JIM-3, OPM-2 and PEL: BC-2, BC-3 (lanes 10-16); MCF-7 breast carcinoma positive control (lane 9).