PTGS2 and neoplasm: Having shown that MFGE8, KLK5, and KLK7 KO not only substantially suppressed tumor metastasis but also restored celecoxib sensitivity to a greater degree compared to other candidate genes, we next focused on these three genes and tested the efficacy of MFGE8, KLK5, and KLK7 individual KO combined with COX-2 inhibition in tumor suppression using an orthotopic xenograft mouse model.