The results presented here represent the first demonstration of CD8+ T cell-dependent control of tumours growing outside the treatment field following PDT; other studies showing inhibition of tumour growth outside the PDT treatment field have not discerned the effector cell type required for control of distant tumours (Gomer et al, 1987; Blank et al, 2001; Castano et al, 2003). Here, CD8A is linked to neoplasm.