HER-2-E0771 mammary tumour cells (2x105) were injected into the fourth inguinal mammary fat pads of female HER-2 TG mice. Six days after tumour injection HER-2 TG mice received total body irradiation (4 Gy) followed by the adoptive transfer of 10x106 control HER-2 CAR-T cells or those in which PTPN2 had been deleted by CRISPR RNP. Mice were injected with IL-2 (50,000 IU/day) on days 0-4 post adoptive CAR-T cell transfer and tumour growth monitored. g) CD45+ CD8+ mCherry+ CAR-T cells numbers were determined in HER-2-E0771 tumours by flow cytometry 19 days post adoptive transfer. 