Effect of NF-E2 (platelet), PAR4, and fibrinogen deficiency on pulmonary metastasis in immunodeficient C.B-17 SCID mice. (A) Nf-E2^-/-, (B) Par4^-/-, and (C) fibrinogen (Fib-/-) mice, and appropriate controls were injected with B16-F10-luc cells via tail vein and killed 14 days later. The number of tumors visible on the lung surface (left panels) or total tumor burden as determined by lung luciferase activity (right panels) was determined. Horizontal lines indicate medians. P values were determined using Mann-Whitney test (A) or Kruskal-Wallis test with Dunn multiple comparison (B-C). ns indicates not significant; ko, knock out; het, heterozygote; and wt, wild type.