Figure 9:

Dual color immunostaining (vimentin: Red, BerEP4: Brown) (Pleural effusion fluid with history of mammary carcinoma). All the usual components of effusion fluids (reactive mesothelial cells and inflammatory cells) are immunoreactive for vimentin (red). Second foreign population is highlighted and easily detectable as vimentin non-immunoreactive component, consistent with metastatic tumor cells. In the adult population, most of these are metastatic adenocarcinoma which are usually immunoreactive for BerEP4 with cytoplasmic and membranous immunostaining (brown). (Red arrows show vimentin immunoreactive red immunostained mesothelial cells and inflammatory cells as usual components of effusion fluids. Brown arrows show BerEP4 immunoreactive brown immunostained second foreign population of adenocarcinoma cells.).