Fig. 1

Immunohistochemical analysis of HER2 expression in gastric carcinomas using the 4B5 antibody in whole-tissue sections. (a) a HER2-positive case (3+); (b) a HER2-equivocal case (2+); (c) a HER2-negative case (1+); (d) intratumoral protein heterogeneity in a HER2-positive case (3+). (A-C: x400 field magnification; D: x200 field magnification)