PODXL and keratoconus: However, knock-in of one copy of ROSA-LSL-Myc in combination with KrasG12D (KrasG12DROSAMyc/+;Pdx-Cre) significantly reduced survival compared to KC mice, which was further reduced by knocking in two copies of ROSA-LSL-Myc (KrasG12DROSAMyc/Myc;Pdx-Cre) (Fig. 3e).