In contrast, tumors that contained PDA cells lacking expression of TGM2 had diminished appearance of the CXCL12–KRT19 coating in both wild-type and TGM2-KO mice, indicating that TGM2 must be expressed by the cancer cell (Fig. 5A and SI Appendix, Fig. S10A). Here, CXCL12 is linked to Patent ductus arteriosus.