Differential pulmonary microcirculatory response to tumor cell emboli as observed in vivo.

Malignant tumors frequently exhibit characteristic patterns of metastatic spread. In the rabbit, the VX2 carcinoma metastasizes to the lung, whereas the Brown-Pearce carcinoma usually spreads to organs distal to this structure. A system of in vivo micros copy has been established in which the response of the microcirculation of the lung has been observed during embolization of tumor cells from these neoplasms. The VX2 tumor characteristically produces microcirculatory arrest or slowing, but the BrownPearce does not show this effect. Microcirculatory response to specific cancer cells may be one of the determinants of metastatic pattern.