We therefore sequenced Trp53 exons in all available tumours and found only 1/11 p21−/−Zmat3−/− tumours to harbour a Trp53 mutation, with considerable higher frequencies seen in lymphomas from the other tested genotypes, p21−/− or Zmat3−/− (Fig. 3E, F, Table S4). This evidence concerns the gene ZMAT3 and lymphoma.