ERBB2 and neoplasm: In the second case, a HER2-nonspecific Affibody (His6-ZTaq:GS-Cys) fluorescent probe was injected in mice with the same HER2-expressing human tumor carcinomas as in the first case, and in the third case, the HER2 specific Affibody (His6-ZHER2:GS-Cys) fluorescent probe was injected in mice with no HER2-expressing tumor.