Fig. 3
Pathological and genetic profiles during the process of cancer-tissue originated spheroid (CTOS) preparation and use of CTOS to evaluate drug efficacy. A Morphological and immunohistochemical staining results during preparation of CTOS. CTOS were established as CTOS lines after at least two in vivo passages of subcutaneous transplantation of CTOS into BRJ mice. The first generation of succeeding tumors in in vivo passage was denoted as CTOS G1 and the second generation as CTOS G2. HE, Hematoxylin Eosin stain; HER2, human epidermal growth factor receptor 2; CK7, Cytokeratin 7; CK20, Cytokeratin 20; GATA3, GATA binding protein 3. B HER2 copy number and HER2 E401G-to-wild-type ratio by droplet digital PCR. The left figure shows the result of HER2 copy number assay; the right figure shows the result of mutation detection assay to check the mutant-to-wild–type ratio. C Drug efficacy evaluation using CTOS. IC50, half maximal inhibitory concentration; T + P, trastuzumab and pertuzumab