Diminished experimental tumor metastasis in fII^MZ animals. Cohorts of fII^WT and fII^MZ animals were challenged with an IV bolus of LLC^GFP. Two weeks later, metastatic foci in the lung were determined. A substantial, statistically significant diminution in the number of lung metastases was noted in the fII^MZ animals compared with fII^WT mice (A). FII^WT animals had prominent metastatic foci (B), whereas many fII^MZ animals demonstrated few, if any, metastases (C). Cohorts of fII^WT and fII^MZ animals were challenged with IV bolus of B16 melanoma. Eighteen days later, metastatic foci in the lung were determined. As was seen with LLC, fII^MZ animals had significantly fewer metastatic foci when compared with fII^WT mice (D). The same pattern was found when comparing fII^WT mice with mice with 50% prothrombin (fII^+/−) (E). Numerous metastatic foci were seen in fII^WT animals (F), whereas metastases were rare in fII^MZ mice (G).