ADAM10 expression in MCL cell lines and patient samples. (A) Western blots showing the expression of the precursor and active/mature forms of ADAM10 in 3 MCL cell lines. Whereas the precursor was highly expressed, the active/mature form was readily detectable only in Jeko-1 and Mino cells. A faint band at 72 kDa, representing the active/mature form of ADAM10, was also detectable in SP53. MCF-7 cells were used as the positive control. PBMCs from a healthy individual (PBMC #1) showed abundant precursor ADAM10 protein but no detectable active/mature ADAM10. (B) Western blots showing the presence of the precursor and active/mature form of ADAM10 in all MCL patient samples (both frozen #1-9 and leukemic #10-12); PBMCs from 2 healthy individuals (#2 and #3) showed no detectable active/mature ADAM10. (C) Immunohistochemistry showing no detectable signal of ADAM10 in the mantle zone of a reactive tonsil. At 100× magnification, the germinal centers showed faint staining (i), one case of MCL tumor showed no detectable ADAM10 (ii), and another MCL tumor showed a relatively high level of ADAM10 expression (iii). On high magnification (1000×), the ADAM10 immunostaining pattern was detectable in both of the nucleus and cytoplasm (iv).