LCK and neoplasm: At 9 days post‐adoptive transfer both tumour and draining lymph node Lck‐Cre;Ptpn2fl/fl OT‐1 T cells were more active, as assessed by the PMA/ionomycin‐induced expression of effector molecules, including IFNγ, TNF and granzyme B (Fig 2C; Appendix Fig S3C).