PRF1 and neoplasm: Analyses of the T-cell activation markers CD69 (Fig. 6e) and perforin (Fig. 6f) revealed that all tumours showed increased T-cell activation compared to normal tissue, and that Vhl∆/∆Trp53∆/∆Rb1∆/∆Hif2a∆/∆ tumours showed higher levels of T-cell activation than Vhl∆/∆Trp53∆/∆Rb1∆/∆ or Vhl∆/∆Trp53∆/∆Rb1∆/∆Hif1a∆/∆ tumours, consistent with our conclusions from the GAGE analyses.