However, the loss of perforin completely abrogated the positive effects of picornavirus vaccination, with TMEV Xho1-OVA8 treated Prf-/- mice (N = 7 mice) displaying tumor progression and survival comparable to control mice receiving TMEV-wt (N = 10 mice) (Fig 4B and 4C). This evidence concerns the gene PRF1 and neoplasm.