To investigate the function of Arg1 in myeloid cells during PDA progression, we generated KrasFrt-STOP-Frt-G12D/+;Ptf1aFlpO/+ (KF); Lyz2Cre/+;Arg1f/f mice, hereafter referred to as KFCA (Figure 2D and Figure 2—figure supplement 1A). This evidence concerns the gene FLT1 and Patent ductus arteriosus.