PRG4 and cancer: The cancer genes most frequently mutated in the mouse LUSC tumors (≥25%, i.e., mutated in at least 4 samples of 16 tumors) were as follows: Muc4, Prg4, Igf2r, Ctsll3, Dlgap1, Hspa9, Armcx3, Cdk1, Pcdhb15, Fus, Gga1, Il2rb, Kmt2d (Mll2), Mapk6, Myh1, Ncoa3 (Src3), Obscn, Runx2, Zmynd8, Ido1, Nkain2, Pyy, Stil, Tcl1b4, Tfeb, and Trpv1 (Figure 1).