HER-2-E0771 tumours at day 10 post adoptive CAR-T cell transfer or from HER-2-E0771 tumours that had re-emerged after being cleared by Lck-Cre;Ptpn2fl/fl CD8+ HER-2 CAR-T cells were analyzed for HER-2 expression by immunohistochemistry. Scale bars: 200 μm (full size) and 70 μm (zoom). 