B220 staining revealed increased B cell density in all tumour genotypes compared to normal tissue, and higher densities in Vhl∆/∆Trp53∆/∆Rb1∆/∆Hif1a∆/∆ tumours than in Vhl∆/∆Trp53∆/∆Rb1∆/∆ or Vhl∆/∆Trp53∆/∆Rb1∆/∆Hif2a∆/∆ tumours (Fig. 6h). This evidence concerns the gene PTPRC and neoplasm.