The reinfusion of COX-1+/+ platelets in both COX-1+/+ (Figure 8, E and F) and COX-1–/– (Supplemental Figure 9D) mice resulted in significantly greater pulmonary retention of tumor cells at 24 hours and enhanced numbers of metastatic lung colonies (Figure 8, G and H) compared with using COX-1–/– platelets. Here, PTGS1 is linked to neoplasm.