Fig. 2

H&E and immunohistochemistry staining of the tumor cell clusters in the pleural effusion. A Cytology of the smear of the effusion (MGG). B H&E staining of the cell block of the effusion. C and D TTF-1 and CEA positive staining of the tumor cells. E Ki67 staining to show the proliferated tumor cells. F CK20 and CK7 double-staining were negative in the tumor cells. Bar = 50 μm