Fig. 5.

Persistently phosphorylated Stat3 correlates with MMP-9 expression in primary breast cancer samples. Immunohistochemistry was performed on sequential sections of 34 primary breast cancer microtissue arrays with antiphospho-Stat3 (pStat3) and anti-MMP-9 antibodies. A schematic overview of the tissue arrays and a summary of the immunohistochemistry results are shown. Representative sections of strong staining are indicated as +++ and shaded in black, moderate staining as ++ and shaded in gray, and weak to no staining as 0/+ and shaded in white. Normal breast had 0/+ staining for both pStat3 and MMP-9. A positive correlation was observed between (+++/++) staining for pStat3 and MMP-9 (P < 0.001) by χ² test.