PRF1 and neoplasm: We either injected immunodeficient Pfp−/−/ Rag2−/− mice with E-/P-selectin expression (WT) or E-/P-selectin knockout (KO) (Sele−/−/Selp−/−) mice subcutaneously (s.c.)with control transfected (shControl) or ITGB4 KD (shITGB4) TCs, resulting in the four experimental groups as illustrated in Fig. 1C. The endpoint of the experiment was a primary tumor size of ~ 1.5 cm3 with the aim to quantify distant metastatic cell loads at this time point.