Previous studies had demonstrated that inhibiting COX-2 or EP4 receptor activity reduced proliferative and spheroid forming ability of COX-2 expressing murine C3L5 mammary cells in vitro22, orthotopic tumor growth and spontaneous metastases in vivo18,21,22 and the incidence of SLC marker positive cells within the residual tumors in treated mice22. The gene discussed is CCL21; the disease is neoplasm.