Immunohistochemical analysis of GPA34 expression. Immunohistochemistry was performed with mAb A34 (#342), according to the ABC method, using DAB chromogen and hematoxylin counterstain. Panels A-C, A34 immunostaining in normal stomach showing: (A) intense immunoreactivity of the stomach fundus mucosa (4x); (B) intense membranous staining of mucosal neck cells (40x), and (C) intense membranous A34 immunostaining of fundic gland epithelia (40x). (D) Intratubular A34 immunoreactivity in testis, with no staining of interstitial tissue (4x). (E) Focal and membranous A34 immunoreactivity in ductal epithelia of the pancreas (10x). (F) Gastric carcinoma with homogeneous immunoreactivity (4x) and (G) intense cytoplasmic and membranous A34 pattern of tumor cells (40x).