PLK4 and neoplasm: Tcf7, a transcription factor expressed in early stage exhausted T cells [22, 23], was also increased in Egr2/3-/- CD8 + TILs in B16 tumours and unchanged in MC38 while genes involved in cell growth (Myb, Plk4, Cdc45, Cks1b, Spc24), DNA repair (Ung1, Neil3) and metabolism (Hk2, Cad, Bcat1, Scd2, Slc7a1, Tfrc) were decreased in Egr2/3-/- CD8 + TILs in both models (Fig. 6A, Supplementary Data files 1 and 2).