Comparative microscopic analysis of metastatic foci in fibrinogen-deficient and control mice.

Representative examples show lung metastases (∗) of B16-BL6 melanoma (A and B) and LLC (C and D) in control mice (A and C) and Fib⁻ mice (B and D). Fibrin(ogen) deposition (appearing as red reaction product in panels A and B and brown staining in panels C and D) is apparent in the lung tissue surrounding the metastatic nodule of the control mice but not in the Fib⁻ mice. The metastases from both genotypes were often pleural based and associated with blood vessels (arrow). Note the dark material in panels A and B is melanin produced by the B16-BL6 cells.