Figure 1.

Correlation between alpha smooth muscle actin and platelet-derived growth factor receptor expression. Immunohistochemical expression of (A) alpha smooth muscle actin (αSMA), (B) platelet-derived growth factor receptor (PDGFR)α and (C) PDGFRβ in spindle-like cells in Patient 5 prior to rituximab treatment (streptavidin-biotin peroxidase ×100). Red arrow in the boxed area points to a spindle-like cell (among others) expressing αSMA, PDGFRα and PDGFRβ.