Human model for studying seed-soil factors in blood-borne metastasis.

The relationship between tumor "seed" and tissue "soil" in blood-borne metastasis is poorly understood. Therefore, an explanatory human model is proposed. It is based on the hypothesis that the spread of lung cancer cells to the adrenal vein provides in man not only a variable attribute, lung cancer seed, but also a constant attribute, adrenal venous soil, as in a scientific experiment. Out of 100 cases of lung cancer, four histologic types proved their invasive potentiality in 45 subjects by colonizing the adrenal parenchyma proper and yet differed appreciably in their ability to grow in the adrenal venous blood. Hence, in all probability, the systematic study of venous blood will help in the discovery of the potentialities and limitations of human blood in tumor metastasis.